Mohammad Kassem, Maria Bokova, Andrey S. Tverjanovich, Daniele Fontanari, David Le Coq, Anton Sokolov, Pascal Masselin, Shinji Kohara, Takeshi Usuki, Alex C. Hannon, Chris J. Benmore and Eugene Bychkov*, Bent HgI₂ Molecules in the Melt and Sulfide Glasses: Implications for Nonlinear Optics, Chem. Mater. 2019. DOI: 10.1021/acs.chemmater.9b00860

Abstract

Nonlinear optical (NLO) crystals are widely used in advanced photonic technologies for second harmonic and difference frequency generation (SHG and DFG, respectively), producing coherent light at frequencies where existing lasers are unavailable. Isotropic glasses do not exhibit SHG or DFG, except temporarily induced anisotropy under external stimuli. However, recent reports on glasses with chiral structural motifs show promising permanent NLO properties. We propose an alternative solution: hybrid molecular/network glasses with noncentrosymmetric HgI₂ monomers. Mercury(II) iodide consists of linear HgI₂ triatomic molecules in the vapor phase and in the yellow orthorhombic polymorph stable above 400 K. At lower temperatures, the tetragonal red form is composed of corner-sharing HgI_4/2 tetrahedra forming a layered extended framework. There is a gap in the molecular evolution; direct structural measurements of the liquid HgI₂ phase are missing. Using high-energy X-ray scattering, pulsed neutron diffraction, and Raman spectroscopy supported by structural and vibrational modeling, we show that the mercury(II) iodide melt and HgI₂-containing sulfide glasses are built up by bent HgI₂ monomers (the bond angle ∠I–Hg–I = 156 ± 2° in the melt). The noncentrosymmetric entities imply intrinsic optical nonlinearity of the second order, confirmed by a strong SHG response.

Dan Wang, Lihui Xiao, Peixia Yang,* Zhengrui Xu, Xiangyu Lu, Lei Du,* Oleg Levin, Liping Ge, Xiaona Pan, Jinqiu Zhang and Maozhong An, Dual-nitrogen-source engineered Fe–N_x moieties as a booster for oxygen electroreduction, J. Mater. Chem. A, 2019, 7, 11007-11015. DOI: 10.1039/C9TA01953G

Abstract

Metal–air batteries, particularly Zn–air batteries, have triggered considerable enthusiasm of communities due to their high theoretical power density. Developing highly active, cost-effective and alternative non-precious metal catalysts for the oxygen reduction reaction (ORR) is pivotal for popularizing zinc–air batteries. The rational design and synthesis of this type of catalyst are therefore critical, but it is still challenging to control the well-defined active sites as expected. Herein, we report a dual-nitrogen-source mediated route for synergistically controlling the formation of active Fe–N_x moieties that are embedded in the carbon matrix. The facile control of coordination structures of precursors by this dual-nitrogen-source approach is revealed to play a key role in this report. Impressively, the optimized dual-nitrogen-source derived catalyst (i.e. Fe–N–C-800) exhibits prominently enhanced ORR activity with a half-wave potential of 0.883 V in alkaline electrolyte, higher by 32 mV and 72 mV than those derived from individual nitrogen sources, which is also further evaluated in primary Zn–air batteries. The enhanced ORR activity of Fe–N–C-800 is attributed to the rich Fe–N_x active sites derived from the dual-nitrogen-source approach.

Maartje J.Levels, Cynthia M.Fehres, Lisa G.M. van Baarsen, Nathalie O.P. van Uden, Kristine Germar, Tom G.O'Toole, Iris C.J.Blijdorp, Johanna F.Semmelink, Marieke E.Doorenspleet, Arjen Q.Bakker, Mikhail Krasavin, Alexey Tomilin, Sophie Brouard, Hergen Spits, Dominique L.P.Baeten, Nataliya G.Yeremenko, BOB.1 controls memory B-cell fate in the germinal center reaction, J. Autoimmun. 2019. DOI: 10.1016/j.jaut.2019.04.011

Abstract

During T cell-dependent (TD) germinal center (GC) responses, naïve B cells are instructed to differentiate towards GC B cells (GCBC), high-affinity long-lived plasma cells (LLPC) or memory B cells (Bmem). Alterations in the B cell-fate choice could contribute to immune dysregulation leading to the loss of self-tolerance and the initiation of autoimmune disease. Here we show that mRNA levels of the transcription regulator BOB.1 are increased in the lymph node compartment of patients with rheumatoid arthritis (RA), a prototypical autoimmune disease caused by the loss of immunological tolerance. Investigating to what extent levels of BOB.1 impact B cells during TD immune responses we found that BOB.1 has a crucial role in determining the B cell-fate decision. High BOB.1 levels promote the generation of cells with phenotypic and functional characteristics of Bmem. Mechanistically, overexpression of BOB.1 drives ABF1 and suppresses BCL6, favouring Bmem over LLPC or recycling GCBC. Low levels of BOB.1 are sufficient for LLPC but not for Bmem differentiation. Our findings demonstrate a novel role for BOB.1 in B cells during TD GC responses and suggest that its dysregulation may contribute to the pathogenesis of RA by disturbing the B cell-fate determination.

D. S. Bolotin, V. Korzhikov-Vlakh, E. Sinitsyna, S. N. Yunusova, V. V. Suslonov, A. Shetnev, A. Osipyan, M. Krasavin, V. Yu. Kukushkin, Biocompatible zinc(II) 8-(dihydroimidazolyl)quinoline complex and its catalytic application for synthesis of poly(L,L-lactide), J. Catal., 372 (2019) 362–369; DOI: 10.1016/j.jcat.2019.03.002.

Abstract

A 1:1 reaction of 8-(dihydroimidazolyl)quinoline (abbreviated as L) with MCl₂·2H₂O (M = Co^II, Ni^II, Cu^II, Zn^II) conducted in EtOAc (for Zn^II and Cu^II) or MeOH (Ni^II and Co^II) at 50 °C for 10 min provided the respective air- and shelf-stable [MCl₂L] complexes (94–96%). The catalytic activity of these well-defined species was evaluated in L-lactide ring-opening polymerization (ROP) that was conducted in the presence of 2-hydroxyethylmethacrylate (HEMA) as a nucleophilic initiator. The biocompatible zinc(II) complex was found to be more catalytically active in ROP compared to the other three complexes as well as SnOct₂, a common reference catalyst. The zinc(II)-catalyzed ROP also gives the macromolecular product with the lowest polydispersity index (1.2). The applicability of the HEMA-terminated PLA, prepared in the presence of the [ZnCl₂L] complex, was demonstrated when PLA was converted into amphiphilic copolymer PLA-PEG via the thiol-ene click reaction. The PLA-PEG copolymer was shown to form nanospheres (calculated mean diameter 95 ± 10 nm) characterized by low particle size distribution. This – along with anticipated lower toxicity of [ZnCl₂L] traces in the polymer – makes these nanospheres potentially applicable as vehicles for intravenous drug delivery.

Lijun Fu, Qunting Qu, Rudolf Holze, Veniamin V. Kondratiev and Yuping Wu, Composites of metal oxides and intrinsically conducting polymers as supercapacitor electrodes: The best of both worlds? J. Mater. Chem. A, 2019. DOI:10.1039/C8TA10587A.

Abstract

Composite materials combining intrinsically conducting polymers and metal oxides suggested as electrode materials in supercapacitors are reviewed with attention to achieved stability and specific functions and effects both components contribute to performance of the materials.

Mikhail V.Dobrynin, Carla Pretorius, Dumisani V.Kama, Andreas Roodt, Vadim P.Boyarskiy, Regina M.Islamova, Rhodium(I)-catalysed cross-linking of polysiloxanes conducted at room temperature, J. Catal., V. 372, 2019, 193-200. DOI: 10.1016/j.jcat.2019.03.004.

Abstract

Acetylacetonate and 4-arylimino-2-pentanonate carbonyl complexes of rhodium(I) [Rh(RC(O)C(R')C(O)R“)(CO)₂] (1: R = Me, R' = H, R'' = Me; 2: R = Me, R' = Cl, R'' = Me; 3: R = Me, R' = H, R'' = CO₂Me; 4: R = Ph, R' = H, R'' = Me; 5: R = Ph, R' = H, R'' = Ph) and [Rh(MeC(NR''')CHC(O)Me)(CO)₂] (6: R''' = Ph; 7: R''' = 2,6-Me₂C₆H₃) were examined as hydrosilylation cross-linking catalysts at RT for the reaction of poly(dimethylsiloxane-co-ethylhydrosiloxane) copolymer with vinyl terminated poly(dimethylsiloxane) or vinyl terminated poly(dimethylsiloxane-co-styrene) copolymer. All complexes allow cross-linking of vinyl- and hydride-containing polysiloxanes and copolymers at RT without inhibitor addition. Complexes 1–7possess catalytic activity comparable to the industrially used complex of Pt⁰ and divinyltetramethyldisiloxane (Karstedt’s catalyst). 1 is the most active among the studied rhodium complexes at 1.0 × 10⁻⁴ mol⋅L⁻¹ and 1.0 × 10⁻⁵ mol⋅L⁻¹. Silicone rubbers obtained with the rhodium catalysts compared to Karstedt’s catalyst possess no visible defects (bubbles or cracks), and differed by improved elastic properties (the elongation at break increased from 160 to 255%) The activity and improved silicone rubber properties using 1 renders it one of the suitable alternatives to Karstedt’s catalyst.

Ekaterina Oleneva, Julia Savosina, Marina Agafonova-Moroz, Alexander Lumpov, Vasily Babain, Igor Jahatspanian, Andrey Legin, Dmitry Kirsanov, Potentiometric multisensor system for tetra- and hexavalent actinide quantification in complex rare earth metal mixtures related to spent nuclear fuel reprocessing, Sensors and Actuators B: Chemical, 2019, 288, 155-162. DOI: 10.1016/j.snb.2019.02.113

Abstract

A potentiometric multisensor system, composed of 12 cross-sensitive sensors, is proposed for uranium and thorium quantification in multi-component mixtures simulating PUREX process tailing solutions. Various ligands with high extraction capacity to lanthanides and actinides were used as active compounds in plasticized polymeric sensor membranes. The sensitivity of the individual sensors to tetra- and hexavalent actinides (UO₂²⁺ and Th⁴⁺) in aqueous nitric acid solutions with pH = 2 has been studied for the first time. The sensors with pronounced sensitivity to actinides were comprised into the multisensor system that was applied for UO²⁺₂and Th⁴⁺ quantitative determination in presence of each other and lanthanides cations (La³⁺, Pr³⁺, Sm³⁺, Gd³⁺, Yb³⁺). The nitric acid quantification in the set of mixtures with UO²⁺₂ and La³⁺ was also performed using the same system. Projection on latent structures (PLS) algorithm was used for multivariate regression models calculation. The results of PLS models validation with independent test set show the possibility of UO²⁺₂ and Th⁴⁺ quantification with mean relative error (MRE) equal to 17% and 14% correspondingly, and HNO₃ quantification with MRE = 7%. This accuracy is appropriate for real-time technological control of PUREX process.

Gomathy Chakkaradhari, Toni Eskelinen, Cecilia Degbe, Andrey Belyaev, Alexey S. Melnikov, Elena V. Grachova, Sergey P. Tunik, Pipsa Hirva, and Igor O. Koshevoy, Oligophosphine-thiocyanate Copper(I) and Silver(I) Complexes and Their Borane Derivatives Showing Delayed Fluorescence, Inorg. Chem., 2019. DOI: 10.1021/acs.inorgchem.8b03166

Abstract

The series of chelating phosphine ligands, which contain bidentate P² (bis[(2-diphenylphosphino)phenyl] ether, DPEphos; 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, Xantphos; 1,2-bis(diphenylphosphino)benzene, dppb), tridentate P³ (bis(2-diphenylphosphinophenyl)phenylphosphine), and tetradentate P⁴ (tris(2-diphenylphosphino)phenylphosphine) ligands, was used for the preparation of the corresponding dinuclear [M(μ₂-SCN)P²]₂ (M = Cu, 1, 3, 5; M = Ag, 2, 4, 6) and mononuclear [CuNCS(P³/P⁴)] (7, 9) and [AgSCN(P³/P⁴)] (8, 10) complexes. The reactions of P⁴ with silver salts in a 1:2 molar ratio produce tetranuclear clusters [Ag₂(μ₃-SCN)(t-SCN)(P⁴)]₂ (11) and [Ag₂(μ₃-SCN)(P⁴)]₂²⁺ (12). Complexes 7–11 bearing terminally coordinated SCN ligands were efficiently converted into derivatives 13–17 with the weakly coordinating ^–SCN:B(C₆F₅)₃ isothiocyanatoborate ligand. Compounds 1 and 5–17 exhibit thermally activated delayed fluorescence (TADF) behavior in the solid state. The excited states of thiocyanate species are dominated by the ligand to ligand SCN → π(phosphine) charge transfer transitions mixed with a variable contribution of MLCT. The boronation of SCN groups changes the nature of both the S₁ and T₁ states to (L + M)LCT d,p(M, P) → π(phosphine). The localization of the excited states on the aromatic systems of the phosphine ligands determines a wide range of luminescence energies achieved for the title complexes (λ_em varies from 448 nm for 1 to 630 nm for 10c). The emission of compounds 10 and 15, based on the P⁴ ligand, strongly depends on the solid-state packing (λ_em = 505 and 625 nm for two crystalline forms of 15), which affects structural reorganizations accompanying the formation of electronically excited states.

Kristina S. Kisel, Alexei S. Melnikov, Elena V. Grachova, Antti J. Karttunen, Antonio Doménech-Carbó, Kirill Yu. Monakhov, Valentin G. Semenov, Sergey P. Tunik, and Igor O. Koshevoy, Supramolecular Construction of Cyanide-Bridged Re^I Diimine Multichromophores, Inorg. Chem., 2019, 58 (3), pp 1988–2000. DOI: 10.1021/acs.inorgchem.8b02974

Abstract

The reactions of labile [Re(diimine)(CO)₃(H₂O)]⁺ precursors (diimine = 2,2′-bipyridine, bpy; 1,10-phenanthroline, phen) with dicyanoargentate anion produce the dirhenium cyanide-bridged compounds [{Re(diimine)(CO)₃}₂CN)]⁺ (1 and 2). Substitution of the axial carbonyl ligands in 2 for triphenylphosphine gives the derivative [{Re(phen)(CO)₂(PPh₃)}₂CN]⁺ (3), while the employment of a neutral metalloligand [Au(PPh₃)(CN)] affords heterobimetallic complex [{Re(phen)(CO)₃}NCAu(PPh₃)]⁺ (4). Furthermore, the utilization of [Au(CN)₂]⁻, [Pt(CN)₄]^2–, and [Fe(CN)₆]^4–/3– cyanometallates leads to the higher nuclearity aggregates [{Re(diimine)(CO)₃NC}_xM]^m+ (M = Au, x = 2, 5 and 6; Pt, x = 4, 7 and 8; Fe, x = 6, 9 and 10). All novel compounds were characterized crystallographically. Assemblies 1–8 are phosphorescent both in solution and in the solid state; according to the DFT analysis, the optical properties are mainly associated with charge transfer from Re tricarbonyl motif to the diimine fragment. The energy of this process can be substantially modified by the properties of the ancillary ligands that allows to attain near-IR emission for 3 (λ_em = 737 nm in CH₂Cl₂). The Re–Fe^II/III complexes 9 and 10 are not luminescent but exhibit low energy absorptions, reaching 846 nm (10) due to Re^I → Fe^IIItransition.

D.V.Zhuzhelskii, E.G.Tolstopjatova, S.N.Eliseeva, A.V.Ivanov, ShouleiMiao, V.V.Kondratiev, Electrochemical properties of PEDOT/WO₃ composite films for high performance supercapacitor application, Electrochimica Acta, 2019, V.209, P.182-190. DOI: 10.1016/j.electacta.2019.01.007

Abstract

Tungsten oxide was electrochemically deposited from a metastable acidic solution of isopolytungstate on glassy carbon electrodes coated by the films of a conducting polymer poly-3,4-ethylenedioxythiophene (PEDOT). The formation of PEDOT/WO₃ composite films during electrochemical deposition of tungsten oxide into the polymer matrix was gravimetrically monitored by EQCM. The morphology of WO₃ deposits was studied using SEM, TEM and EDX analysis, including element mapping and depth concentration profile of main elements. SEM and TEM images of PEDOT/WO₃ composites show disperse distribution of WO₃ precipitates in the porous matrix of PEDOT, possessing high surface area and pore volume, effective for charge transport. Electrochemical behavior of PEDOT/WO₃ was investigated in 0.5 M H₂SO₄ by cyclic voltammetry, galvanostatic charge-discharge method and electrochemical impedance spectroscopy. The WO₃ component in the obtained PEDOT/WO₃ composite electrodes exhibited high specific capacitance of 689 F g⁻¹ in the potential range −0.3–0.0 V. The work presents a simple approach for the synthesis of PEDOT/WO₃ composites with high values of specific capacitance. The obtained results indicate that PEDOT/WO₃ composite could be a promising electrode material for supercapacitor applications.

Anton V. Rozhkov, Mariya A. Krykova, Daniil M. Ivanov, Alexander S. Novikov, Anna A. Sinelshchikova, Marina V. Volostnykh, Mikhail A. Konovalov, Mikhail S. Grigoriev, Yulia G. Gorbunova, Vadim Yurievich Kukushkin, Reverse Arene Sandwich Structures Based upon π‐hole•••[MII] (d8M = Pt, Pd) Interactions, where Positively Charged Metal Centers Play the Role of a Nucleophile, Angew. Chem. Int. Ed., Accepted Author Manuscript. DOI: 10.1002/ange.201814062

Abstract

The complexes [Pt(tpp)] (M = Pt; H2tpp = tetraphenyl‐porphyrin), [M(acac)2] (M = Pd, Pt, Hacac = acetylacetone), and [Pd(ba)2] (Hba = benzoylacetone) were co‐crystallized with highly electron‐deficient arene systems to form reverse arene sandwich structures built by π‐hole•••[MII] (d8M = Pt, Pd) interactions. The adduct [Pt(tpp)]•2C6F6 is monomeric, whereas the diketonate 1:1 adducts form columnar infinity 1D‐stack assembled by simultaneous action of both π‐hole•••[MII] and C–F interactions. The reverse sandwiches are based on noncovalent interactions and calculated ESP distributions indicate that in π‐hole•••[MII] contacts, [MII] plays the role of a nucleophile.

Kamran T.Mahmudov, Vadim Yu.Kukushkin, Atash V.Gurbanova, Mikhail A.Kinzhalov, Vadim P.Boyarskiy, M. Fátima C. Guedesda Silva, Armando J.L.Pombeiro, Isocyanide metal complexes in catalysis, Coordination Chemistry Reviews, 384, 65–89, 2019. DOI: 10.1016/j.ccr.2019.01.002

Abstract

The catalytic applications of isocyanide metal systems (from early to late transition metals) for organic transformations were systematically reviewed, and the studied transformations are also classified by type regardless of the metal center. A broad range of catalytic reactions of organic substrates has been developed including reactions of alkenes and alkynes, functionalization of E–H and E–E to multiple bonds, alkyl- and aryl-halides activation, nucleophilic addition, electron transfer catalysis, and photochemical reactions. This report gives a general overview of reaction routes, mechanisms, and driving forces and highlights the potential of isocyanide metal species, drawing attention to emerging putative targets.

Valeria Belikova, Vitaly Panchuk, Evgeny Legin, Anastasia Melenteva, Dmitry Kirsanov, Andrey Legin Continuous monitoring of water quality at aeration plant with potentiometric sensor array, Sensors and Actuators B: Chemical, 282, 2019, 854-860. DOI: 10.1016/j.snb.2018.11.153

Abstract

The potential of multisensor array in continuous on-line monitoring of processed water quality at aeration plant is explored. The responses of 23 potentiometric sensors were continuously registered every seven seconds through the 26 days of experiment in a special container having connection with outlet water line of the aeration plant. Using chemometric tools it is shown that potentiometric “electronic tongue” is capable of evaluation of two important parameters of water quality: ammonium nitrogen and nitrate nitrogen. Unlike traditional sampling-based analysis the results of multisensor are available immediately in a real-time mode. Moreover, the achieved precision is sufficient to monitor possible alarm events. The employment of topological data analysis allowed for exploration of the very large dataset (295,828 measurements) accumulated through the long period of continuous measurements with sensors and for judgment on stability of water quality.

Oliver Hegen, Jens Braese, Alexey Y. Timoshkin, Manfred Scheer, Bidentate Phosphanyl- and Arsanylboranes, Chem. Eur. J., 2018. DOI:10.1002/chem.201804772

Abstract

A new class of neutral bidentate ligands with pnictogenyl-functional sites has been obtained. The reaction of tmeda⋅(BH₂ I)₂ (1, tmeda=tetramethylethylendiamine) with different phosphanides yields the corresponding bidentate phosphanylboranes tmeda⋅(BH₂ PH₂ )₂ (2 a), tmeda⋅(BH₂ PPh₂ )₂ (2 b), and tmeda⋅(BH₂ tBuPH)₂ (2 c). This reaction strategy could be further extended to synthesize the first bidentate arsanylborane tmeda⋅(BH₂ AsPh₂ )₂ (3). Depending on the substituents on the phosphorus, these compounds form different Au^I complexes, to build either polymeric tmeda⋅(BH₂ PH₂ AuCl)₂ (4 a), or monomeric tmeda⋅(BH₂ PPh₂ AuCl)₂ (4 b) products. These compounds form also neutral oligomeric group 13/15 chain-like molecules by coordination to a boron moiety such as tmeda⋅(BH₂ PH₂ BH₃ )₂ (5 a) and tmeda⋅(BH₂AsPh₂ BH₃ )₂ (5 b). DFT calculations provide insight into the differences between the syntheses of mono- and bidentate pnictogenylboranes.

Reutskaya, E.; Osipyan, A.; Sapegin, A.; Novikov, A.; Krasavin, M. Rethinking Hydrolytic Imidazoline Ring Expansion: A Common Approach to the Preparation of Medium-Sized Rings via Side Chain Insertion into [1.4]Oxa- and [1.4]Thiazepinone Scaffold. J. Org. Chem. 2019, In press. DOI: 10.1021/acs.joc.8b02805

Abstract

The previously reported ring-expansion strategy involving hydrolytically prone imidazoline rings was thought to include the formation of a hydrated imidazoline intermediate. In this work, we accessed the latter via the addition of a 2-aminoethyl side chain onto a lactam moiety. This led to an efficient three-atom ring expansion of diarene-fused [1.4]oxazepines and [1.4]thiazepines and led us to propose to term this common approach the hydrated imidazoline ring expansion (HIRE) reaction. The strategy was extended to the insertion of longer (containing up to five atoms) side chains, and thus, larger (11- to 12-membered) diarene-fused rings were obtained via the homo-HIRE and homo²-HIRE reactions, respectively. This underscores the utility of the HIRE reaction for the preparation of medium-sized rings, an important class of chemical tools for interrogation of various biological targets.

Krasavin, M.; Shetnev, A.; Sharonova, T.; Baykov, S.; Kalinin, S.; Nocentini, A.; Sharoyko, V.; Poli, G.; Tuccinardi, T.; Presnukhina, S.; Tennikova, T. B.; Supuran, C. T. Continued exploration of 1,2,4-oxadiazole periphery for carbonic anhydrase-targeting primary arene sulfonamides: discovery of subnanomolar inhibitors of membrane-bound hCA IX isoform that selectively kill cancer cells in hypoxic environment. Eur. J. Med. Chem. 2019, accepted. DOI: 10.1016/j.ejmech.2018.12.049

Abstract

An expanded set of diversely substituted 1,2,4-oxadiazole-containing primary aromatic sulfonamides was synthesized and tested for inhibition of human carbonic anhydrase I, II, IX and XII isoforms. The initial biochemical profiling revealed a significantly more potent inhibition of cancer-related, membrane-bound isoform hCA IX (reaching into submicromolar range), on top of potent inhibition of hCA XII that is another cancer target. The observed structure-activity relationships have been rationalized by molecular modeling. Comparative single-concentration profiling of the carbonic anhydrase inhibitors synthesized for antiproliferative effects against normal (ARPE-19) and cancer (PANC-1) cell lines under chemically induced hypoxia conditions revealed several candidate compounds selectively targeting cancer cells. More in-depth characterization of these leads revealed two structurally related compounds that showed promising selective cytotoxicity against pancreatic cancer (PANC-1) and melanoma (SK-MEL-2) cell lines.

Alexandra V.Smikhovskaia, Maxim S.Panov, Ilya I.Tumkin, Evgeniia M.Khairullina, Sergey S.Ermakov, Irina A.BalovaMikhail N.Ryazantsev, Vladimir A.Kochemirovsky In situ laser-induced codeposition of copper and different metals for fabrication of microcomposite sensor-active materials, Analytica Chimica Acta Volume 1044, 31 December 2018, Pages 138-146. DOI: 10.1016/j.aca.2018.07.042

Abstract

We report one-step in situ laser-induced synthesis of the conductive copper microstructures doped with iron, zinc, nickel, and cobalt with highly developed surface area. It was observed that the presence of chlorides of the aforementioned metals in the solutions used in our experiments increases the deposition rate and the amount of copper in the resulting deposits; it also leads to the deposit miniaturization. The laser deposition from solutions containing cobalt (II) chloride of concentration more than 0.003 M results in fabrication of copper microelectrode with better electrochemical properties than those deposited from solutions containing chlorides of other metals of the same concentration. Moreover, copper microelectrode doped with cobalt has demonstrated good reproducibility and long-run stability as well as sensitivity and selectivity towards determination of hydrogen peroxide(limit of detection-0.2 μM) and d-glucose (limit of detection-2.2 μM). Thus, in this article we have shown the opportunity to manufacture two-phase microcomposite materials with good electrical conductivity and electrochemical characteristics using in situ laser-induced metal deposition technique. These materials might be quite useful in development of new perspective sensors for non-enzymatic detection of such important analytes as hydrogen peroxide and glucose.

Anatoly A.Vereshchagin, Petr S.Vlasov, Alexander S.Konev, Galina A.Grechishnikova, Oleg V.Levin Novel highly conductive cathode material based on stable-radical organic framework and polymerized nickel complex for electrochemical energy storage devices, Electrochimica Acta, DOI: 10.1016/j.electacta.2018.11.149. DOI: 10.1016/j.electacta.2018.11.149

Abstract

Redox polymers bearing stable nitroxyl radical groups, such as poly-TEMPO-methacrylate (PTMA), are attractive candidates for application in power sources of novel kind, which combine the high power output of supercapacitors and high energy of rechargeable batteries. An important advantage of PTMA is the availability and low cost of the starting materials combined with high charging/discharging voltage, fast electron transfer kinetics and good mechanical properties of the polymer. However, low electron conductivity and high solubility in common organic electrolytes hamper the broad application of TEMPO-based compounds as cathode materials. In the present work, we report a simple strategy to overcome these limitations by the use of a practical and polymer-rich electrode based on redox-conducting polymer blends of polymerized nickel complexes with salen-type Schiff bases and PTMA. Electrochemical properties of the material are tested both in thin film systems and in asymmetric supercapacitor prototypes with aqueous electrolyte, which demonstrate high specific capacity (83 mAh g⁻¹ at 1C, 53 mAh g⁻¹ at 5C and 47 mAh g⁻¹ at 10C), high rate capability as well as cycling stability (55% capacity retention after 1000 cycles).

Daniil A. Lukyanov, Alexander S. Konev, Konstantin Amsharov, Alexander F. Khlebnikov*, and Andreas Hirsch Diastereospecific and Highly Site-Selective Functionalization of C₇₀Fullerene by a Reaction with Diethyl N-Arylaziridine-2,3-dicarboxylates, J. Org. Chem., 2018, 83 (22), pp 14146–14151. DOI: 10.1021/acs.joc.8b02240

Abstract

The diastereospecific and highly site-selective cycloaddition of N-arylazomethine ylides generated in situ from diethyl N-arylaziridine-2,3-dicarboxylates to C₇₀ fullerene is reported. The reaction provides C₇₀ fulleropyrrolidines in up to hundreds on a milligram scale as α- and β-adducts in a 4:1 ratio with a controlled stereochemical outcome: cis-aziridines give exclusively trans-adducts, and trans-aziridines give only cis-adducts. The ¹H and ¹³C{¹H} NMR spectra for different isomeric adducts were recorded and analyzed to identify some characteristic features, which permit an easy identification of isomeric adducts of this type.

Pavel A. Sakharov , Mikhail S. Novikov , and Alexander F. Khlebnikov* 2-Diazoacetyl-2H-azirines: Source of a Variety of 2H-Azirine Building Blocks with Orthogonal and Domino Reactivity, J. Org. Chem., V. 83, P. 8304−8314, 2018. DOI: 10.1021/acs.joc.8b01004

Abstract

A synthesis of 2-diazoacetyl-2H-azirines was developed starting from 2H-azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles. 2-Diazoacetyl-2H-azirines easily undergo reactions characteristic of α-diazo ketones with preservation of the azirine ring. Reactions with hydrohalogenic, carboxylic, and p-toluenesulfonic acids provide novel 1-(3-aryl-2H-azirin-2-yl)-2-halo- and 2-(R-oxy)ethan-1-ones in good yields. The synthesized 2H-azirines can offer many possibilities for chemical manipulation in heterocyclic synthesis, due to the presence of highly reactive azirine and the exocyclic C(O)–CHN₂ or C(O)–CH₂X functionalities, which can show orthogonal or domino reactivity. The synthetic usefulness of the developed building blocks was demonstrated by the preparation of new types of heterocyclic dyads (azirine–oxazole, azirine–pyrazoline, azirine–thiazole, azirine–oxirane, pyrrole–oxazole) as well as an azirine chalcone analogue, 2-azidoacetyl-2H-azirine, and 2-diazoacetylaziridine derivatives.

Kirill I. Mikhailov , Ekaterina E. Galenko , Alexey V. Galenko , Mikhail S. Novikov , Alexander Yu. Ivanov, Galina L. Starova, and Alexander F. Khlebnikov* Fe(II)-Catalyzed Isomerization of 5-Chloroisoxazoles to 2H-Azirine-2-carbonyl Chlorides as a Key Stage in the Synthesis of Pyrazole–Nitrogen Heterocycle Dyads, J. Org. Chem., V. 83, P. 3177–3187, 2018. DOI: 10.1021/acs.joc.8b00069

Abstract

2-(1H-Pyrazol-1-ylcarbonyl)-2H-azirines were synthesized by in situ trapping of 2H-azirine-2-carbonyl chlorides, generated by Fe(II)-catalyzed isomerization of 5-chloroisoxazoles, with pyrazoles. According to DFT calculations, the selectivity of nucleophilic substitution at the carbonyl group of 2H-azirine-2-carbonyl chloride by a pyrazole nucleophile, which is a mixture of two tautomers, is controlled by thermodynamic factors. 2-(1H-Pyrazol-1-ylcarbonyl)-2H-azirines are excellent precursors for the preparation of two other pyrazole–nitrogen heterocycle dyads: 5-(1H-pyrazol-1-yl)oxazoles by photolysis and 1-(1H-pyrrol-2-ylcarbonyl)-1H-pyrazoles by a Ni(II)-catalyzed reaction with 1,3-dicarbonyl compounds. 5-(1H-Pyrazol-1-yl)oxazoles show strong emission in acetonitrile at 360–410 nm with high quantum yields.

Manfred Scheer, Oliver Hegen, Jens Braese, Alexey Timoshkin Bidentate Phosphanyl- and Arsanylboranes, Chem. Eur. J., 2018, early view. DOI: 10.1002/chem.201804772.

Abstract

A new class of neutral bidentate ligands with pnictogenyl-functional sites have been obtained. The reaction of tmeda∙(BH2I)2 (1, tmeda = tetramethylethylendiamine) with different phosphanides yields the corresponding bidentate phosphanylboranes tmeda∙(BH2PH2)2 (2a), tmeda∙(BH2PPh2)2 (2b) and tmeda∙(BH2tBuPH)2 (2c). This reaction strategy could be further extended to synthesize the first bidentate arsanylborane tmeda∙(BH2AsPh2)2 (3). Depending on the substituents on the phosphorus, these compounds form different Au(I) complexes, to build either polymeric tmeda∙(BH2PH2AuCl)2 (4a), or monomeric tmeda∙(BH2PPh2AuCl)2 (4b) products. These compounds form neutral oligomeric group 13/15 chain-like molecules by coordination to a boron moiety such as tmeda∙(BH2PH2BH3)2 (5a) and tmeda∙(BH2AsPh2BH3)2 (5b). DFT calculations provide insight into the differences between the syntheses of mono- and bidentate pnictogenylboranes.

Haschke S, Mader M, Schlicht S, Roberts AM, Angeles-Boza AM, Barth JAC, Bachmann J. Direct oxygen isotope effect identifies the rate-determining step of electrocatalytic OER at an oxidic surface, Nature Communicationsvolume 9, Article number: 4565 (2018). DOI: 10.1038/s41467-018-07031-1.

Abstract

Understanding the mechanism of water oxidation to dioxygen represents the bottleneck towards the design of efficient energy storage schemes based on water splitting. The investigation of kinetic isotope effects has long been established for mechanistic studies of various such reactions. However, so far natural isotope abundance determination of O₂ produced at solid electrode surfaces has not been applied. Here, we demonstrate that such measurements are possible. Moreover, they are experimentally simple and sufficiently accurate to observe significant effects. Our measured kinetic isotope effects depend strongly on the electrode material and on the applied electrode potential. They suggest that in the case of iron oxide as the electrode material, the oxygen evolution reaction occurs via a rate-determining O-O bond formation via nucleophilic water attack on a ferryl unit.

Maxim Shevtsov, Stefan Stangl, Boris Nikolaev, Ludmila Yakovleva, Yaroslav Marchenko, Ruslana Tagaeva, Wolfgang Sievert, Emil Pitkin, Anton Mazur, Peter Tolstoy, Oleg Galibin, Vyacheslav Ryzhov, Katja Steiger, Oleg Smirnov, William Khachatryan, Kerry Chester, Gabriele Multhoff, Granzyme B Functionalized Nanoparticles Targeting Membrane Hsp70‐Positive Tumors for Multimodal Cancer Theranostics, Small, V. 15, P. 1900205, 2019. DOI: 10.1002/smll.201900205

Abstract

Functionalized superparamagnetic iron oxide nanoparticles (SPIONs) have emerged as potential clinical tools for cancer theranostics. Membrane‐bound 70 kDa heat shock protein (mHsp70) is ubiquitously expressed on the cell membrane of various tumor types but not normal cells and therefore provides a tumor‐specific target. The serine protease granzyme B (GrB) that is produced as an effector molecule by activated T and NK cells has been shown to specifically target mHsp70 on tumor cells. Following binding to Hsp70, GrB is rapidly internalized into tumor cells. Herein, it is demonstrated that GrB functionalized SPIONs act as a contrast enhancement agent for magnetic resonance imaging and induce specific tumor cell apoptosis. Combinatorial regimens employing stereotactic radiotherapy and/or magnetic targeting are found to further enhance the therapeutic efficacy of GrB‐SPIONs in different tumor mouse models.

Muhammad Abdullah Butt, Antonino Calà Lesina, Martin Neugebauer, Thomas Bauer, Lora Ramunno, Alessandro Vaccari, Pierre Berini, Yuriy Petrov, Denis Danilov, Alina Manshina, Peter Banzer, Gerd Leuchs, Investigating the Optical Properties of a Laser Induced 3D Self‐Assembled Carbon–Metal Hybrid Structure, Small, 2019, V.15, 1900512. DOI: 10.1002/smll.201900512

Abstract

Carbon‐based and carbon–metal hybrid materials hold great potential for applications in optics and electronics. Here, a novel material made of carbon and gold–silver nanoparticles is discussed, fabricated using a laser‐induced self‐assembly process. This self‐assembled metamaterial manifests itself in the form of cuboids with lateral dimensions on the order of several micrometers and a height of tens to hundreds of nanometers. The carbon atoms are arranged following an orthorhombic unit cell, with alloy nanoparticles intercalated in the crystalline carbon matrix. The optical properties of this metamaterial are analyzed experimentally using a microscopic Müller matrix measurement approach and reveal a high linear birefringence across the visible spectral range. Theoretical modeling based on local‐field theory applied to the carbon matrix links the birefringence to the orthorhombic unit cell, while finite‐difference time‐domain simulations of the metamaterial relates the observed optical response to the distribution of the alloy nanoparticles and the optical density of the carbon matrix.

T.V.Plisko, A.V.Penkova, K.S.Burts, A.V.Bildyukevich, M.E.Dmitrenko, G.B.Melnikova, R.R.Atta, A.S.Mazur, A.A.Zolotarev, A.B.Missyul, Effect of Pluronic F127 on porous and dense membrane structure formation via non-solvent induced and evaporation induced phase separation, Journal of Membrane Science, V. 580, Pages 336-349. DOI: 10.1016/j.memsci.2019.03.028

Abstract

Novel porous and dense membranes based on polysulfone (PSF) modified by poly(ethylene glycol)–b–poly(propylene glycol)–b– poly(ethylene glycol) (Pluronic F127) were developed. The influence of Pluronic F127 introduction to the casting solution on different types of polymer membrane formation via two different phase inversion techniques—non-solvent induced phase separation (NIPS) for porous membranes and evaporation induced phase separation (EIPS) for dense membranes—was investigated. According to the triangular phase diagram obtained, PSF-Pluronic F127-N,N-dimethylacetamide (DMAc) systems feature lower critical solution temperature and have a tendency to micelle formation due to Pluronic F127 self-assembly. The structure, hydrophilic-hydrophobic balance and physicochemical properties of PSF-Pluronic F127 membranes were characterized by water contact angle measurements, scanning electron microscopy, nuclear magnetic resonance, small-angle X-ray scattering, and atomic force microscopy. The performance of dense membranes in pervaporation separation of water-ethyl acetate mixtures was investigated to reveal the effect of Pluronic F127 on the structure and free volume of the PSF-Pluronic F127 membranes. It was shown that Pluronic F127 introduction to the casting solution during membrane formation via two different techniques (NIPS and EIPS) leads to the increase in the pore size of the porous membranes and free volume of the dense membranes, as well as the increase in flux and surface hydrophilicity for both membrane types. Pluronic F127 was found to improve the antifouling performance of porous PSF-Pluronic F127 membranes in the BSA solution ultrafiltration. The introduction of 3 wt% Pluronic F127 into dense PSF membrane improved permeation flux in 1.7 and 2.7 times (15.1 and 27.3 g/(m²h)) at high selectivity level (100 wt% water in the permeate) during the separation of ethyl acetate-water mixtures (2 and 4 wt% ethyl acetate) compared to pristine PSF membrane.

Kögel J.F., Timoshkin A.Y., Schröder A., Lork E., Beckmann J., Al(OCAr^F₃)₃ - A Thermally Stable Lewis Superacid Chem. Science, 2018, doi 10.1039/c8sc02981d, IF = 9.1

Синтезирована и охарактеризована новая суперкислота Льюиса Al(OCArF3)3 (ArF = C6F5), термически устойчивая до 180 С. Исследована её реакционная способность по отношению к основаниям Льюиса и показано, что в результате взаимодействия Al(OCArF3)3 с F- и Cl- получаются слабокоординированные ионы, стабилизирущие различные катионные формы.

Abstract

The adduct free Lewis superacid Al(OCAr^F₃)₃ was obtained by the reaction of Ar^F₃COH with AlEt₃ and fully characterized (Ar^F = C₆F₅). It comprises a high thermal stability up to 180 °C and a distinct reactivity towards Lewis bases, as exemplified by the isolation of the neutral adducts Al(OCAr^F₃)·D (D = MeCN, THF, Et₂O, pyridine, OPEt₃), the fluoride complexes [Q][FAl(OCAr^F)₃] (Q⁺ = Cs⁺, Ag⁺, Tl⁺, [S(NMe₂)₃]⁺, [Ph₃C]⁺, Li⁺, [NBu₄]⁺, [FeCp₂]⁺) and the chloride complex [Ph₃C][ClAl(OCAr^F)₃].

Agafonova A.V., Smetanin I.A., Rostovskii N.V., Khlebnikov A.F., Novikov M.S. Expedient synthesis of 3-hydroxypyrroles via Bu3SnH-triggered ionic 5-exo-trig-cyclization of 5-chloro-3-azamuconoate derivatives Org. Chem. Front. 2018, doi 10.1039/c8qo00982a, IF=5.455

Описано принципиально новое применение трибутилоловогидрида в качестве реагента для ионной восстановительной 1,5-циклизации 3-азамуконоатов. На основе новой реакции 1,5-экзо-триг-циклизации 5-хлор-3-азамуконоатов разработан эффективный двухстадийный метод получение 4-гидрокси-1Н-пиррол-3-карбоновой и 3-гидрокси-1Н-пиррол-2,4-дикарбоновых кислот производные из легкодоступных диазоэфиров и 2-хлор-2Н-азиринов или 4-хлоизоксазолов.

Abstract

An unprecedented application of tributyltin hydride (TBTH) as a reagent for the reductive ionic 1,5-cyclization of 3-azamuconoates (3-azahexa-2,4-dienedioates) is described. A novel 1,5-exo-trig-cyclization of 5-chloro-3-azamuconoates was used as a base for the development of an effective two-step method for the preparation of 4-hydroxy-1H-pyrrole-3-carboxylic and 3-hydroxy-1H-pyrrole-2,4-dicarboxylic acids derivatives from readily available diazo esters and 2-chloro-2H-azirines or 4-chloroisoxazoles. The experimental results, as well as the DFT calculations of the pyrroles formation, are in good agreement with the ionic mechanism involving the initial hydride attack at the CN bond of the azamuconoate followed by tin-promoted 1,5-cyclization.

Anastasia I. Solomatina, Pavel S. Chelushkin, Tatiana O. Abakumova, Vladimir A. Zhemkov, Mee-Whi Kim, Ilya Bezprozvanny, Vladislav V. Gurzhiy, Alexey S. Melnikov, Yuri A. Anufrikov, Igor O. Koshevoy, Shih-Hao Su, Pi-Tai Chou, Sergey P. Tunik Reactions of Cyclometalated Platinum(II) [Pt(N^C)(PR₃)Cl] Complexes with Imidazole and Imidazole-Conjugated Biomolecules: Fine-Tuning Reactivity and Photophysical Properties via Ligand Design, Inorg. Chem., 2018. Article in Press. DOI: 10.1021/acs.inorgchem.8b02204 IF=4.7

Подробно исследованы химические и структурные аспекты конъюгации комплексов [Pt(N^C)PR3Cl] с убиквитином и альбумином. Быстрая, выборочная и количественная координация комплекса платины с имидазольной функцией белков позволяет их региоселективную маркировку, а также открывает путь к применению конъюгатов для количественного картирования концентрации кислорода в клетках с использованием PLIM микроскопии.

Abstract

Chemical and structural aspects of the [Pt(N^∧C)PR₃Cl] complexes conjugation with ubiquitin and albumin were investigated in detail. Rapid, selective, and quantitative coordination of the platinum complex to imidazole function of the proteins enabled their regioselective labeling and also paves the way to application of the conjugates in quantitative mapping of oxygen concentration in cells using PLIM microscopy.

J.R. Shakirova, E.V. Grachova, V.V. Gurzhiy, Senthil Kumar Thangaraj, J. Jänis, A.S. Melnikov, A.J. Karttunen, S.P. Tunik, I.O. Koshevoy, Heterometallic cluster-capped tetrahedral assemblies with postsynthetic modification of the metal cores Angew. Chem. Int. Ed., (2018), doi: 10.1002/anie.201809058

Взаимодействие политопных алкинильных лигандов с Au-Cu кластерами приводит к образованию трехмерных агрегатов, которые демонстрируют фосфоресценцию при комнатной температуре (Φem = 0,6). Эта люминесценция происходит из металл-центрированного возбужденного состояния вследствие переноса заряда с металла на лиганд. Супрамолекулярные Au-Cu агрегаты могут быть легко преобразованы в изоструктурные Au-Ag аналоги путем прямого обмена ионов металлов в растворе. Эта модификация меняет природу эмиссии на внутрилигандную, что представляет собой необычный пример подобного "переключения" электронной структуры для металлорганических соединений.

Abstract

Combining the star‐shaped alkynyl ligands with low‐nuclearity gold–copper triphosphane clusters produces 3D metallocage aggregates, which demonstrate room temperature phosphorescence in solution (max Φ_em=0.6). Their luminescence mainly originates from cluster‐localized metal‐to‐ligand charge transfer excited state. These supramolecular assemblies can be easily converted into the isostructural gold‐silver congeners by the direct exchange of the metal ions. Such modification of the terminal metal cores switches the emission to the intraligand (alkyne) electronic transitions of the triplet manifold, that represents an unusual optical functionality among the metallocycle/metallocage complexes.

Dekina D.I., Kalinichev A.V., Pokhvishcheva N.V., Peshkova M.A., Mikhelson K.N. Effects of quantitative composition of the sensing phase in the response of ionophore-based optical sensors Sensors & Actuators: B. Chemical, V.277, N. 20, P. 535-543, doi: 10.1016/j.snb.2018.09.018

На основе теоретических представлений количественно проанализировано влияние состава сенсорного слоя оптодов на основе ионофоров на характеристики их отклика: рабочий диапазон и чувствительность.

Abstract

The response characteristics of the optical chemical sensors (optodes), namely response range, response span and sensitivity are quantitatively related to the composition of the sensor phase for the first time. The dependence of the characteristics of ion-selective bulk optodes on the concentrations of the indicator, ionophore and ionic additive (ion-exchanger) are simulated numerically and experimentally verified with Na⁺- and K⁺-selective colorimetric optodes. It is shown how the response span, response range, median and sensitivity depend on the sensor membrane composition. Response curves with an intermediate plateau are predicted theoretically and obtained experimentally. It is shown that the inflection point in the response curve does not necessarily refers to α = 0.5. The results can be used for the fine tuning of the optical response of chemical sensors.

Lu, X., Du, L., Wang, D., Yang, P., Liu, L., Zhang, J., An, M., Levin, O., Wang, J., Ge, L. Highly Dispersed Cu−N_X Moieties Embedded in Graphene: A Promising Electrocatalyst towards the Oxygen Reduction Reaction, ChemElectroChem, (2018). Article in Press. DOI: 10.1002/celc.201800657

В статье предложен простой метод синтеза катализатора реакции восстановления кислорода на основе Cu-Nх допированного графена.

Abstract

Transition metal–carbon–nitrogen catalysts for the oxygen reduction reaction (ORR) are promising and challenging. Cu is a potential transition metal to form efficient ORR catalysts for fuel cells. Herein, a facile method is developed to synthesize a highly dispersed Cu−N_X and N‐doped graphene (Cu−N−G) catalyst. The Cu−N−G catalyst shows a half‐wave potential (E_1/2) of 0.859 V, which is comparable to the commercial Pt/C catalyst (0.856 V), and is among the best compared with the previously reported Cu‐based materials. In addition, such a catalyst shows good stability and methanol tolerance in alkaline media. A synergy of doped N (pyridinic and graphitic N) and Cu−N_X moieties as well as the pore structure are revealed to account for the enhanced ORR activity.

M. A. Kinzhalov, M. V. Kashina, E. A. Mozheeva, A. S. Mikherdov, D. M. Ivanov, A. S. Novikov, A. S. Smirnov, M. A. Kryukova, A. Yu. Ivanov, S. N. Smirnov, V. Yu. Kukushkin, K. V. Luzyanin, Dramatically enhanced solubility of halide-containing organometallic species in diiodomethane: the role of solvent•••complex halogen bonding Angew. Chem. Int. Ed., 57 (2018), doi: 10.1002/anie.201807642

Роль галогенных связей в растворимости металлорганических соединений.

Abstract

In the current study, we evaluated the solubility of a number of organometallic species and showed that it is noticeably improved in diiodomethane when compared to other haloalkane solvents. The better solvation properties of CH₂I₂ were associated with the substantially better σ‐hole‐donating ability of this solvent, which results in the formation of uniquely strong solvent–(metal complex) halogen bonding. The strength of the halogen bonding is attenuated by the introduction of additional halogen atoms in the organometallic species owing to the competitive formation of more favourable intermolecular complex–complex halogen bonding. The exceptional solvation properties of diiodomethane and its inertness towards organometallic species make this solvent a good candidate for NMR studies, in particular, for the acquisition of spectra of insensitive spins.

Zimin D.P., Dar’in D.V., Rassadin V.A., Kukushkin V. Yu. Gold-Catalyzed Hydrohydrazidation of Terminal Alkynes Org. Lett., 20 (16), pp 4880–4884, 2018, doi: 10.1021/acs.orglett.8b02019

Статья посвящена неописанной ранее в литературе реакции между терминальными ацетиленами, активированными комплексами золота (I), и различными гидразидами. В результате реакции получаются практически значимые кето-N-ацилгидразоны с выходами от хороших до отличных. Реакция изучена на широком круге субстратов, обладает высокой толерантностью к функциональным группам, в ней используются простые субстраты, реакция проводится в мягких условиях.

Abstract

Facile gold-catalyzed hydrohydrazidation of alkynes with various hydrazides R²CONHNH₂ (R = Alk or Ar; including those with an additional nucleophilic moiety) in the presence of Ph₃PAuNTf₂ (6 mol %) leading to a wide range of substituted keto-N-acylhydrazones (18 examples) in excellent to good yields (99–66%) is reported. This novel metal-catalyzed coupling proceeds under mild conditions (chlorobenzene, 60 °C), exhibits high functional group tolerance, and is insensitive to the electronic and steric effects of the substituents in the reactants.

Jack C. Gee, Beth A. Fuller, Hannah-Marie Lockett, Gita Sedghi, Craig M. Robertson, Konstantin V. Luzyanin Visible light accelerated hydrosilylation of alkynesusing platinum–[acyclic diaminocarbene] photocatalysts, Chem. Comm. 2018, 54, 9450–9453, doi: 10.1039/c8cc04287j

Применение комплексов платины с диаминокарбеновыми лигандами в качестве фотокатализаторов реакции гидросилилирования алкинов. Реакция гидросилилирования с использование данных соединений значительно ускоряется при помощи использования видимого синего света; применения внешнего фотокатализатора при этом не требуется. Границы применения метода включают терминальные и интернальные алкины и ряд гидросиланов.

Abstract

Platinum–[diaminocarbene] complexes work as transition-metal photocatalysts for the hydrosilylation of alkynes. A catalytic system operates under visible light irradiation (blue LED) enabling the conversion of a range of terminal and internal alkynes to respective vinyl silanes in excellent yields.

Pomogaeva A.V., Timoshkin A.Y., Scheer M.  Why do B-P and Al-P polymers differ? Structures, stability and electronic properties of chain and ring [H2PEH2]n oligomers (E = B, Al; n = 1-15), Chem. Eur. J., V. 24, 2018, doi: 10.1002/chem.201803008

Статья посвящена анализу структурных, энергетических и электронных характеристик олигомерных соединений (H2EPH2)n, E=B,Al; n=1-15 на основании квантово-химических расчетов различными DFT методами. Рассмотрены цепные и циклические олигомеры и показано, что они имеют принципиально разные электронные свойства.

Abstract

Chain and ring [H2PEH2]n oligomers (E = B, Al; n = 2‐15) have been computationally studied at the B3LYP/def2‐TZVP level of theory. A strong tendency to cyclization is found for the chain Al‐P oligomers with n > 7, while analogous long B‐P oligomers can exist as chain structures. Subsequent oligomerization enthalpies approach each other very closely for the ring and chain oligomers with the increase of n. However, these oligomers have very different electronic properties with band gaps below 0.2 eV for the chain [H2PBH2]15 and more than 5 eV for the ring isomer [H2PEH2]15. The MOs in the ring oligomers are highly delocalized, while, for the chain isomers, HOMO and LUMO are localized at the different ends of the oligomeric chain.

Alexandra V Smikhovskaia, Maxim S Panov, Ilya I Tumkin, Evgeniia M Khairullina, Sergey S Ermakov, Irina A Balova, Mikhail N Ryazantsev, Vladimir A Kochemirovsky  In situ laser-induced codeposition of copper and different metals for fabrication of microcomposite sensor-active materials, Analytica Chimica Acta, 2018, doi: 10.1016/j.aca.2018.07.042

Предложен синтез ряда биметаллических композитных сенсоров. Полученные сенсоры были протестированы на определение глюкозы и пероксида водорода.

Abstract

We report one-step in situ laser-induced synthesis of the conductive copper microstructures doped with iron, zinc, nickel, and cobalt with highly developed surface area. It was observed that the presence of chlorides of the aforementioned metals in the solutions used in our experiments increases the deposition rate and the amount of copper in the resulting deposits; it also leads to the deposit miniaturization. The laser deposition from solutions containing cobalt (II) chloride of concentration more than 0.003 M results in fabrication of copper microelectrode with better electrochemical properties than those deposited from solutions containing chlorides of other metals of the same concentration. Moreover, copper microelectrode doped with cobalt has demonstrated good reproducibility and long-run stability as well as sensitivity and selectivity towards determination of hydrogen peroxide (limit of detection-0.2 μM) and d-glucose (limit of detection-2.2 μM). Thus, in this article we have shown the opportunity to manufacture two-phase microcomposite materials with good electrical conductivity and electrochemical characteristics using in situ laser-induced metal deposition technique. These materials might be quite useful in development of new perspective sensors for non-enzymatic detection of such important analytes as hydrogen peroxide and glucose.

Hegen O., Virovets A.V., Timoshkin A.Y., Scheer M.   The Lewis base stabilized diphenylsubstituted Arsanylborane – A versatile building block for arsanylborane oligomers, Chem. Eur. J., V. 24, 2018, doi: 10.1002/chem.201804341

Синтезированы и охарактеризованы донорно-стабилизировнные фенилзамещённые арсанилбораны. Исследованы их реакции с кислотами Льюиса и окисление элементами 16 группы.

Abstract

The synthesis and properties of the Lewis base stabilized diphenylsubstituted arsanylborane Ph2AsBH2SMe2 (1) and Ph2AsBH2NMe3 (2) are reported. These compounds were obtained by the reaction of KAsPh2 with IBH2‐LB (LB = SMe2, NMe3). Compounds 1 and 2 can be used as starting materials for oligomeric/polymeric arsinoboranes. The neutral species, H3B‐Ph2AsBH2NMe3 (3) and Br3B‐Ph2AsBH2NMe3 (4), are synthesized by the reaction with either H3B or Br3B. Through reaction with IBH2‐LB (LB = SMe2, NMe3), the cationic oligomeric group 13/15 compounds [(Me3NBH2Ph2AsBH2NMe3)(I)] (5) and [{H2B(Ph2AsBH2NMe3)2}(I)] (6) were synthesized. All compounds were completely characterized. In addition, the oxidation of Ph2AsBH2NMe3 with chalcogenes was studied. Whereas both the sulfur Ph2As(S)BH2NMe3 (7b) and selenium Ph2As(Se)BH2NMe3 (7c) oxidation products could be isolated and fully characterized, the bis(trimethylsilyl)peroxide oxidated arsinoborane Ph2As(O)BH2NMe3 (7a) is not stable enough and could only be characterized in solution. DFT computations support the decomposition pathway of this compound.

I.O. Koshevoy, V. Sivchik, Rajib Sarker, Zong-Ying Liu, Kun-You Chung, E.V. Grachova, A.J. Karttunen, and Pi-Tai Chou, Improvement of the photophysical performance of platinum cyclometalated complexes in halogen bonded adducts, Chem. Eur. J., 2018, 24, 11475–11484, doi: 10.1002/chem.201802182

Три группы люминесцирующих платиновых комплексов [Pt(C^N)(L)(Y)] были исследованы как акцепторы галогенной связи в отношении иодфторбензолов (IC6F5 и I2C6F4). Производные фосфиноцианида (L/Y = PPh3/CN) кристаллизуются совместно как с IC6F5, так и с I2C6F4. В то время как нативные комплексы являются довольно плохими люминофорами в твердом состоянии (Φ = 0,02-0,09), аддукты проявляют до 10-кратного увеличения интенсивности свечения с незначительным изменением энергии эмиссии. Наблюдаемое усиление квантовой эффективности объясняется главным образом совместным влиянием нековалентных взаимодействий, которые регулируют режим кристаллической упаковки.

Abstract

Three groups of luminescent platinum complexes [Pt(C^N)(L)(Y)] [C^N=benzothienyl‐pyridine (1), bezofuryl‐pyridine (2), phenyl‐pyridine (3); L/Y=DMSO/Cl (a), PPh₃/Cl (b), PPh₃/CN (c)] have been probed as halogen‐bond (XB) acceptors towards iodofluorobenzenes (IC₆F₅ and I₂C₆F₄). Compounds 1 a and 2 a (L/Y=DMSO/Cl) afford the adducts 1 a⋅⋅⋅I₂C₆F₄ and 2 a⋅⋅⋅I₂C₆F₄, which feature I⋅⋅⋅S_btpy/I⋅⋅⋅π_btpy and I⋅⋅⋅O_DMSO/I⋅⋅⋅Cl short contacts, respectively. The phosphane‐cyanide derivatives 1 c and 2 c (L/Y=PPh₃/CN) co‐crystallise with both IC₆F₅ and I₂C₆F₄. None of the phpy‐based species 3 a–3 c participated in XB interactions. Although the native complexes are rather poor luminophores in the solid state (Φ_em=0.023–0.089), the adducts exhibit an up to 10‐fold increase of the intensity with a minor alteration of the emission energy. The observed gain in the quantum efficiency is mainly attributed to the joint influence of non‐covalent interactions (halogen/hydrogen bonding, π–π stacking), which govern the crystal‐packing mode and diminish the radiationless pathways for the T₁→S₀ transition by providing a rigid environment around the chromophore.

Koronatov A.N., Rostovskii N.V., Khlebnikov A.F., Novikov M.S. Rh(II)-Catalyzed Ring Expansion of Pyrazoles with Diazocarbonyl Compounds as a Method for the Preparation of 1,2-Dihydropyrimidines, J. Org. Chem., 2018, doi: 10.1021/acs.joc.8b01228

В работе описана новая Rh(II)-катализируемая реакция диазокарбонильных соединений с 1,4-ди- и 1,4,5-тризамещенным пиразолами как первый пример внедрения карбеноида в простую связь N-N. Эта новая реакция представляет собой новый подход к 4-незамещенным 1,2-дигидропиримидинам, позволяющий осуществлять широкое варьирование функциональных групп в целевом гетероцикле. Согласно DFT расчетам, расширение пиразольного цикла протекает через последовательное образование связанного с металлом пиразолиевого илидая, свободного пиразолиевого илида и 1,5-диазагексатриена,претерпевающего 1,6-циклизацию на последней стадии домино процесса.

Abstract

A high yield synthesis of 1,2-dihydropyrimidines by the Rh(II)-catalyzed reaction of diazocarbonyl compounds with 1,4-di- and 1,4,5-trisubstituted pyrazoles is reported. This reaction represents the first example of a carbenoid insertion into a N–N bond and provides a novel approach to 4-unsubstituted 1,2-dihydropyrimidines with a broad range of functional group tolerance. According to DFT calculations, the pyrazole ring expansion proceeds via the sequential formation of the metal-bound pyrazolium ylide, metal-free pyrazolium ylide, and 1,5-diazahexatriene followed by 1,6-cyclization.).

Maria P. Sokolova, Michael A. Smirnov, Artemiy A. Samarov, Natalya V. Bobrova, Vitaly K. Vorobiov, Elena N. Popova, Elizaveta Filippova, Pavel Geydt, Erkki Lahderanta, Alexander M. Toikka Plasticizing of chitosan films with deep eutectic mixture of malonic acid and choline chloride, Carbohydrate Polymers, V. 197, 548–557, 2018, doi: 10.1016/j.carbpol.2018.06.037

Получены и исследованы пленки хитозана, содержащие глубокий эвтектический растворитель (DES) на основе малоновой кислоты и хлориде холина. Содержание DES варьировалось от 0 до 82 вес%. Анализ изотерм сорбции воды, данные атомно-силовой микроскопии и результаты Фурье ИК-спектроскопии подтвердили сильное взаимодействие хитозана с компонентами ДЭС. Пластифицирующий эффект DES отражают проведенные статические объемные механические измерения, термический анализ и количественное наномеханическое картирование (QNM). Введение DES в пленки хитозана приводит к температуре стеклования в области +2 - 2.3 °C. Результаты QNM подтверждают однородность пленок, содержащих до 75 мас.% DES.

Abstract

Chitosan (CS) films containing deep eutectic solvent (DES) based on malonic acid (MA) and choline chloride (ChCl) were successfully prepared by solution casting method by using DES content ranging from 0 to 82 wt%. A strong interaction of CS with the components of DES was demonstrated by analyses of water sorption isotherms, atomic force microscopy and FTIR results. The plasticizing effect of the MA and ChCl mixture on the CS matrix was shown by static bulk mechanical measurements, thermal analysis and quantitative nanomechanical mapping (QNM). Elongation at break increased from 3 to 62% at increase of DES content from 0 to 67 wt%, while further increase of DES content led to the decreasing of maximal elongation. Introduction of DES into CS films led to the appearance of glass transition temperature in the region +2 - -2.3 °C. QNM results indicated homogeneity of the films containing up to 75 wt% of DES.

I. Mínguez-Bacho,a F. Scheler,a P. Büttner,a K. Bley,b N. Vogel*b and J. Bachmann, Ordered nanopore arrays with large interpore distances via one-step anodization, Nanoscale, 2018,10, 8385-8390, doi: 10.1039/C8NR02215A

Создание структурированных подложек из оксида алюминия с использованием технологий "снизу вверх", совместимых с приложениями нанотехнологий, по-прежнему является актуальной проблемой. Мы представляем новый подход для создания высокоупорядоченных структур в анодированном оксиде алюминия с большими расстояниями между нанопорами с помощью прямого одноэтапного процесса анодирования. Использование прозрачных изоляторов делает такие анодные слои применимыми в качестве шаблонов для наноструктурированных фотовольтаических или фотоэлектрохимических устройств.

Abstract

Preparation of pre-patterned alumina substrates using bottom-up techniques compatible with nanotechnology applications is still a challenge. We present a novel methodology to achieve superior order in ‘anodic’ alumina with large interpore distances by a convenient one-step anodization process. The use of transparent insulators renders such anodic layers applicable as templates for nanostructured photovoltaic or photoelectrochemical devices.

K.S. Kisel, T. Eskelinen, W. Zafar, P. Hirva, E.V. Grachova, S.P. Tunik, I.O. Koshevoy Chromophore-functionalized phenanthro-diimine ligands and their Re(I) complexes, Inorg. Chem., (2018), doi: 10.1021/acs.inorgchem.8b00422

Синтезирован ряд дииминовых лигандов на основе 2-пиридил-1Н-фенантро[9,10-d]имидазола (L1, L2). Связывание основного мотива L1 с антраценсодержащими фрагментами дает бихромофорные соединения L3-L5, из которых L4 и L5 принимают донор-акцепторную архитектуру. L1-L5 показывают сильную флуоресценцию в жидкой среде, демонстрируют обратимый отклик на изменение pH, для L4 и L5 наблюдается эмиссионный сольватохромиз. Лиганды L1-L5 использовали для синтеза соответствующих комплексов Re(I), которые демонстрируют необычную двойную эмиссию синглетного и триплетного происхождения.

Abstract

A series of diimine ligands has been designed on the basis of 2-pyridyl-1 H-phenanthro[9,10- d]imidazole (L1, L2). Coupling the basic motif of L1 with anthracene-containing fragments affords the bichromophore compounds L3-L5, of which L4 and L5 adopt a donor-acceptor architecture. The latter allows intramolecular charge transfer with intense absorption bands in the visible spectrum (lowest λabs 464 nm (ε = 1.2 × 104 M-1 cm-1) and 490 nm (ε = 5.2 × 104 M-1 cm-1) in CH2Cl2 for L4 and L5, respectively). L1-L5 show strong fluorescence in a fluid medium (Φem = 22-92%, λem 370-602 nm in CH2Cl2); discernible emission solvatochromism is observed for L4 and L5. In addition, the presence of pyridyl (L1-L5) and dimethylaminophenyl (L5) groups enables reversible alteration of their optical properties by means of protonation. Ligands L1-L5 were used to synthesize the corresponding [Re(CO)3X(diimine)] (X = Cl, 1-5; X = CN, 1-CN) complexes. 1 and 2 exhibit unusual dual emission of singlet and triplet parentage, which originate from independently populated 1ππ* and 3MLCT excited states. In contrast to the majority of the reported Re(I) carbonyl luminophores, complexes 3-5 display moderately intense ligand-based fluorescence from an anthracene-containing secondary chromophore and complete quenching of emission from the 3MLCT state presumably due to the triplet-triplet energy transfer (3MLCT → 3ILCT).

Scheer M., Braese J., Schinabeck A., Bodensteiner M., Yersin H., Timoshkin A.Y. Gold(I) Complexes Containing Phosphanyl- and Arsanylborane Ligands, Chem. Eur. J., 2018, 24, 10073–10077, doi: 10.1002/chem.201802682

Синтезированы и структурно охарактеризованы комплексы золота (I) с фосфанил- и арсанилборанами. Некоторые соединения проявляют люминесценцию. Электронная структура комплексов проанализирована методами DFT.

Abstract

The structural and photophysical properties of a series of new Au(I) compounds have been studied. The reactions of AuCl(tht) with the phosphanyl‐ and arsanylboranes RR'EBH2NMe3 (E = P, As; R = H, Ph; R' = H, Ph, tBu) afford the complexes [AuCl(RR'EBH2NMe3)]. In the solid state, [AuCl(H2PBH2NMe3)]2 (2a) is a dimer showing unsupported intermolecular aurophilic interactions with short Au…Au distances. In contrast, [AuCl(H2AsBH2NMe3)]n (2b) aggregates to form 1D chains. Organic substituents on the pnictogen atoms lead to discrete molecules in [AuCl(RR'PBH2NMe3)] (2c: R = H, R' = tBu; 2d: R = R' = Ph). To increase the aurophilicity, the ionic homoleptic complexes [Au(RR'EBH2NMe3)2][AlCl4] (3a‐d) have been synthesized for which 3a,b form chains in the solid state and exhibit luminescence. The emissions show a drastic red shift with temperature decrease correlating with decreasing Au...Au distances. DFT calculations provide insight into the bonding situation of the products.

Vitaly Panchuk, Valentin Semenov, Andrey Legin, and Dmitry Kirsanov Signal Smoothing with PLS Regression, Anal. Chem., 2018, 90 (9), pp 5959–5964

Предложен новый способ цифровой фильтрации приборных сигналов

Abstract

Smoothing of instrumental signals is an important prerequisite in data processing. Various smoothing methods were suggested through the last decades each having their own benefits and drawbacks. Most of the filtering methods are based on averaging in a certain window (e.g., Savitzky-Golay) or on frequency-domain representation (e.g., Fourier filtering). The present study introduces novel approach to signal filtering based on signal variance through PLS (projections on latent structures) regression. The influence of filtering parameters on the smoothed spectrum is explained and real world examples are shown.

Sergey A. Adonin, Mikhail Bondarenko, Pavel A. Abramov, Alexander S. Novikov, Pavel E Plyusnin, Maxim N. Sokolov, Vladimir P. Fedin Bromo‐ and polybromoantimonates (V): structural and theoretical studies of hybrid halogen‐rich halometalate frameworks, Chem. Eur. J., 2018, 24, 10165–10170

Реакция "[SbBr6]3‐ +Br2 + HBr + CationBrx" приводит к образованию бромидных/полибромидных комплексов с 0D-, 1D-, 2D- и 3D-супрамолекулярными структурами и различным соотношениям Br/Sb. Новые соединения были охарактеризованы посредством рентгеноструктурного и термогравиметрического анализов, а природа и энергетика нековалентных взаимодействий Br---Br в этих соединениях была изучена с помощью квантово-химических расчётов в рамках теории функционала плотности.

Abstract

Cation‐dependent reactions "[SbBr6]3‐ +Br2 + HBr + CationBrx" result in formation of bromide/polybromide complexes with zero‐, one‐, two‐ or three‐dimensional supramolecular frameworks and different Br/Sb ratio (up to 11). Seven new compounds representing 6 structural types were characterized by XRD and TG; DFT calculations enabled estimation of the energies of the Br···Br contacts (1.1‐4.6 kcal/mol).

S. Heinl, A. Y. Timoshkin, J. Müller, M. Scheer Unexpected differences in the reactivity between the phosphorus and arsenic derivatives [(Cp^BIGFe)₂(µ,η^4:4-E₄)] (E = P and As), Chem. Commun., 2018, 54, 2244-2247

Статья посвящена исследованию структуры и реакционной спсобности комплексов [{CpBIGFe(CO)2}2(μ,η1:1-E4)] E=P,As). Показано, что при фотолизе происходит удаление СО с образованием двухпалубных сэндвичевых комплексов [(CpBIGFe)2(μ,η4:4-Е4)], причем структуры комплексов фософора и мышьяка существенно различаются.

Abstract

Different reaction pathways were determined between thermolysis and photolysis reactions of the butterfly complex [{Cp^BIGFe(CO)₂}₂(μ,η^1:1-As₄)] (1b). The thermolysis leads to novel arsenic-rich compounds [(Cp^BIGFe)₂(μ,η^4:4-As₄)] (2b), [(Cp^BIGFe)₃(μ₃,η^4:4:4-As₆)] (4) and [Cp^BIGFe(η⁵-As₅)] (5), whereas the photolysis of [{Cp^BIGFe(CO)₂}₂(μ,η^1:1-E₄)] (1a: E = P; 1b: E = As) exclusively results in the decarbonylation products [(Cp^BIGFe)₂(μ,η^4:4-P₄)] (2a), 2b and [(Cp^BIGFe)(μ,η^4:1-As₄)(Cp^BIGFe(CO)₂)] (3). The E₄ complexes 2a and 2b show unique structural differences in the solid state despite their related compositions.

N. Glebko, Thuy Minh Dau, A.S. Melnikov, E.V. Grachova, I.V. Solovyev, A. Belyaev, A.J. Karttunen and I.O. Koshevoy Luminescence thermochromism of gold(I) phosphane-iodide complexes: a rule or an exception? Chem. Eur. J., 2018, 24, 3021–3029.

С использованием политопных лигандов, несущих «мягкую» фосфорную и «жесткую» кислородную функции, была синтезирована серия биядерных комплексных соединений Au(I). Все соединения этой серии полностью охарактеризованы при помощи спектроскопии ЯМР, в том числе с использованием 2D методик, элементного анализа и монокристального РСА.  Полученные соединения являются яркими люминофорами в твердой фазе с широкими полосами эмиссии, максимум которых лежит в районе 450–600 нм. Большой Стоксовский сдвиг и зависимость времени жизни люминесценции от кислорода подтверждает преимущественно триплетный характер эмиссии. Было обнаружено, что параметры эмиссии (квантовые выходы и времена жизни возбужденных состояний) соединений зависят от температуры.

Abstract

A series of gold(I) iodide complexes 1–11 have been prepared from di-, tri-, and tetraphosphane ligands. Crystallographic studies reveal that the di- (1–7) and tetrametallic (11) compounds feature linearly coordinated gold(I) ions with short aurophilic contacts. Their luminescence behavior is determined by the combined influence of the phosphane properties, metal–metal interaction, and intermolecular lattice-defined interactions. The proposed variable contribution of ³(X+M)-centered (X=halogen; M=metal) and ³XLCT (halogen to ligand charge transfer) electronic transitions into the lowest lying excited state, which is influenced by supramolecular packing, is presumably responsible for the alteration of room-temperature emission color from green (λ=545 nm, for 11) to near-IR (λ=698 nm, for 2). Dinuclear compounds 6 and 7 exhibit distinct luminescence thermochromism with a blueshift up to 5750 cm⁻¹ upon cooling. Such dramatic change of emission energy is assigned to the presence of two coupled triplet excited states of ³ππ* and ³(X+M)C/³XLCT nature, the presence of which depends on both molecular structure and the crystal lattice arrangement.

Stefanie Schlicht, Sandra Haschke, Vladimir Mikhailovskii, Alina Manshina, Julien Bachmann Highly Reversible Water Oxidation at Ordered Nanoporous Iridium Electrodes Based on an Original Atomic Layer Deposition, ChemElectroChem 2018

Впервые созданы нанопористые иридиевые электроды и исследована их  электрохимическая активность для реакции окисления воды (выделения кислорода). Электроды представляют собой нанопористый анодированный алюминий, с морфологией прямых цилиндрических нанопор. Стенки нанопор с помощью атомно-слоевого осаждения покрыты металлическим слоем иридия. Продемонстрировано, что такие электроды обеспечивают достижение умеренных плотностей тока при очень низких перенапряжениях, что делает такие электроды перспективными для создания аккумуляторов с высокой степенью реверсивности.

Abstract

Nanoporous iridium electrodes are prepared and electrochemically investigated towards the water oxidation (oxygen evolution) reaction. The preparation is based on ‘anodic’ aluminum oxide templates, which provide straight, cylindrical nanopores. Their walls are coated using atomic layer deposition (ALD) with a newly developed reaction which results in a metallic iridium layer. The ALD film growth is quantified by spectroscopic ellipsometry and X-ray reflectometry. The morphology and composition of the electrodes are characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Their catalytic activity is quantified for various pore geometries by cyclic voltammetry, steady-state electrolysis, and electrochemical impedance spectroscopy. With an optimal pore length of L≈17–20 μm, we achieve current densities of J=0.28 mA cm⁻² at pH 5 and J=2.4 mA cm⁻² at pH 1. This platform is particularly competitive for achieving moderate current densities at very low overpotentials, that is, for a high degree of reversibility in energy storage.

Mikherdov A. S., Novikov A. S., Kinzhalov M. A., Boyarskiy V. P., Starova G. L., Kukushkin V. Yu., Halides Held by Bifurcated Chalcogen-Hydrogen Bonds. Effect of µ_(S,N-H)Cl Contacts on Dimerization of Cl(carbene)PdII Species, Inorg. Chem. 2018, 57 (6), pp 3420–3433

В работе описан новый тип нековалентных взаимодействий — бифуркатные халькогенные/водородные связи µ(Сhal,E-H)X. Изучено влияния данного типа взаимодействий на димеризацию диамикарбеновых комплексов палладия.

Abstract

The reaction of cis-[PdCl₂(CNCy)₂] (1) with thiazol-2-amines (2–10) leads to the C,N-chelated diaminocarbene-like complexes [PdCl{C(N(H)4,5-R₂-thiazol-2-yl)NHCy}(CNCy)] (11–14; 82–91%) in the case of 4,5-R₂-thiazol-2-amines (R, R = H, H (2), Me, Me (3), −(CH₂)₄– (4)) and benzothiazol-2-amine (5) or gives the diaminocarbene species cis-[PdCl₂{C(N(H)Cy)N(H)4-R-thiazol-2-yl}(CNCy)] (15–19; 73–93%) for the reaction with 4-aryl-substituted thiazol-2-amines (R = Ph (6), 4-MeC₆H₄ (7), 4-FC₆H₄ (8), 4-ClC₆H₄ (9), 3,4-F₂C₆H₃ (10)). Inspection of the single-crystal X-ray diffraction data for 15–17 and 19 suggests that the structures of all these species exhibit previously unrecognized bifurcated chalcogen–hydrogen bonding μ_(S,N–H)Cl and also Pd^II···Pd^II metallophilic interactions. These noncovalent interactions collectively connect two symmetrically located molecules of 15–17 and 19, resulting in their solid-state dimerization. The existence of the μ_(S,N–H)Cl system and its strength (6–9 kcal/mol) were additionally verified/estimated by a Hirshfeld surface analysis and DFT calculations combined with a topological analysis of the electron density distribution within the formalism of Bader’s theory (AIM method) and NBO analysis. The observed noncovalent interactions are jointly responsible for the dimerization of 15–19 not only in the solid phase but also in CHCl₃ solutions, as predicted theoretically by DFT calculations and confirmed experimentally by FTIR, HRESI-MS, ¹H NMR, and diffusion coefficient NMR measurements. Available CCDC data were processed under the new moiety angle, and the observed μ_(S,E–H)Cl systems were classified accordingly to E (E = N, O, C) type atoms.

Nikolay Solovyev, Evgenii Drobyshev, Geir Bjørklund, Yaroslav Dubrovskii, Roman Lysiuk, Margaret P. Rayman Selenium, selenoprotein P, and Alzheimer's disease: is there a link? Free Radical Biology and Medicine, 2018

Обзор о роли селена и селенопротеина Р в патологии болезни Альцгеймера.

Abstract

The essential trace element, selenium (Se), is crucial to the brain but it may be potentially neurotoxic, depending on dosage and speciation; Se has been discussed for decades in relation to Alzheimer's disease (AD). Selenoprotein P (SELENOP) is a secreted heparin-binding glycoprotein which serves as the main Se transport protein in mammals. In vivo studies showed that this protein might have additional functions such as a contribution to redox regulation. The current review focuses on recent research on the possible role of SELENOP in AD pathology, based on model and human studies. The review also briefly summarizes results of epidemiological studies on Se supplementation in relation to brain diseases, including PREADViSE, EVA, and AIBL. Although mainly positive effects of Se are assessed in this review, possible detrimental effects of Se supplementation or exposure, including potential neurotoxicity, are also mentioned. In relation to AD, various roles of SELENOP are discussed, i.e. as the means of Se delivery to neurons, as an antioxidant, in cytoskeleton assembly, in interaction with redox-active metals (copper, iron, and mercury) and with misfolded proteins (amyloid-beta and hyperphosphorylated tau-protein).

Nikita Kuznetsov, Peixia Yang, Georgy Gorislov, Yuri Zhukov, Vladimir Bocharov, Valery Malev, Oleg Levin Electrochemical transformations of polymers formed from nickel (II) complexes with salen-type ligands in aqueous alkaline electrolytes, Electrochimica Acta, 2018

В работе изучен метод получения наноструктурированного гидроксида никеля из плёнок полимерных комплексов. Полученные материалы демонстрируют высокую каталитическую активность по отношению к реакциям электроокисления спиртов в щелочных растворах.

Abstract

The polymeric nickel complexes with salen-type ligands can serve as useful materials for a range of applications, including catalytic systems and energy storage devices. Despite the fact that electrochemical properties of such complexes were investigated in detail in non-aqueous solutions, there has still remained scarce information about their behavior in aqueous systems. This work is devoted to studying such properties of poly[Ni(salen)] films in aqueous alkaline electrolytes. By combination of electrochemical methods with X-ray photoelectron and Raman spectroscopy it was shown that the redox transformations observed result in ligand exchange and formation of nickel hydroxide thin films deposited on the working electrodes. The obtained material consists of uniformly distributed nanoparticles with the characteristic size of about 10 nm. Catalytic activity of the produced modified electrodes in reactions of ethanol and methanol oxidation, as well as their ability to be charged and discharged reversibly for more than 1000 cycles, makes them promising materials for applications in catalytic and energy storage devices.