Ivan V. Smolyaninov

Bio: Ivan V. Smolyaninov is an academic researcher from Astrakhan State Technical University. The author has contributed to research in topics: Redox & Ligand. The author has an hindex of 16, co-authored 83 publications receiving 801 citations. Previous affiliations of Ivan V. Smolyaninov include Russian Academy & Russian Academy of Sciences.

New dioxygen-inert triphenylantimony(v) catecholate complexes based on o-quinones with electron-withdrawing groups

Abstract: New triphenylantimony(v) catecholate complexes were synthesized by oxidative addition of sterically hindered o-benzoquinones containing electron-withdrawing substituents in different positions of the carbon ring to triphenylantimony. The complexes were characterized using IR spectroscopy, NMR spectroscopy, and cyclic voltammetry. The oxygen-inertness of the complexes is shown by NMR spectroscopy and electrochemical studies. The introduction of electron-withdrawing substituents to the catecholate ligand shifts the first oxidation potential of the complexes to the electropositive region and thus deactivates the triphenylantimony(v) catecholate complexes in the reaction with molecular oxygen.

Cobalt complexes with hemilabile o-iminobenzoquinonate ligands: a novel example of redox-induced electron transfer.

Abstract: The tetracoordinated square-planar CoIII complex (imSQC(O)Ph)CoIII(APC(O)Ph) (1) bearing a radical anion and the closed-shell o-amidophenolate forms of the functionalized o-aminophenol H2LC(O)Ph were synthesized. The intermediate spin state (SCo = 1) CoIII center was found for compound 1. The cyclic voltammogram of derivative 1 contains two oxidative processes and one reductive redox process as well as an additional multi-electron wave at high negative potentials above −2 V, which can involve both the ligand and metal center. One-electron oxidation of 1 by silver triflate produces the [(imSQC(O)Ph)CoII(imQC(O)Ph)]OTf·2toluene (2) derivative with the trigonal prismatic coordination environment of the metal arising from the additional coordination of –C(O)Ph hemilabile groups. This is a first example of a trigonal prismatic coordination polyhedron in cobalt-based complexes featuring o-iminobenzoquinone ligands. The trigonal prismatic geometry achieved by the unique flexibility of the ligand allows metal-to-ligand redox-induced electron transfer (RIET). Chemical oxidation of complex 1 promotes the reduction of CoIII to CoII in compound 2 due to the redox-active nature of o-iminobenzoquinonate ligands. Remarkably, this is the first example of RIET in cobalt-based derivatives with this type of ligand. The oxidative states of the ligands and cobalt ion in both complexes were unequivocally established according to the X-ray data collection by using the utility of “metric oxidation state” (MOS). The spin states of the metal centers were unambiguously determined by density functional theory. The strong antiferromagnetic exchange via metal–ligand interactions is dominant in compounds 1 and 2, giving the doublet (S = 1/2) and triplet (S = 1) ground spin state, respectively.

Trianionic pincer and pincer-type metal complexes and catalysts

Abstract: Trianionic pincer and pincer-type ligands are the focus of this review Metal ions from across the periodic table, from main group elements, transition metals, and the rare earths, are combined with trianionic pincer ligands to produce some of the most interesting complexes to appear in the literature over the past decade This review provides a comprehensive examination of the synthesis, characterization, properties, and catalytic applications of trianionic pincer metal complexes Some of the interesting applications employing trianionic pincer and pincer-type complexes include: (1) catalyzed aerobic oxidation, (2) alkene isomerization, (3) alkene and alkyne polymerization, (4) nitrene and carbene group transfer, (5) fundamental transformations such as oxygen-atom transfer, (6) nitrogen-atom transfer, (7) O2 activation, (8) C–H bond activation, (9) disulfide reduction, and (10) ligand centered storage of redox equivalents (ie redox active ligands) Expansion of the architecture, type of donor atoms, chelate ring size, and steric and electronic properties of trianionic pincer ligands has occurred rapidly over the past ten years This review is structured according to the type of pincer donor atoms that bind to the metal ion The type of donor atoms within trianionic pincer and pincer-type ligands to be discussed include: NCN3−, OCO3−, CCC3−, redox active NNN3−, NNN3−, redox active ONO3−, ONO3−, and SNS3− Since this is the first review of trianionic pincer and pincer-type ligands, an emphasis is placed on providing the reader with in-depth discussion of synthetic methods, characterization data, and highlights of these complexes as catalysts

Binuclear Metal Centers in Plant Purple Acid Phosphatases: Fe-Mn in Sweet Potato

Abstract: Purple acid phosphatases comprise a family of binuclear metal-containing acid hydrolases, representatives of which have been found in animals, plants, and fungi. The goal of this study was to characterize purple acid phosphatases from sweet potato tubers and soybean seeds and to establish their relationship with the only well-characterized plant purple acid phosphatase, the FeIII-ZnII-containing red kidney bean enzyme. Metal analysis indicated the presence in the purified sweet potato enzyme of 1.0 g-atom of iron, 0.6-0.7 g-atom of manganese, and small amounts of zinc and copper. The soybean enzyme contained 0.8-0.9 g-atom of iron, 0.7-0.8 g-atom of zinc per subunit, and small amounts of manganese, copper, and magnesium. Both enzymes exhibited visible absorption maxima at 550-560 nm, with molar absorption coefficients of 3200 and 3300 M(-1) cm(-1), respectively, very similar to the red kidney bean enzyme. Substrate specificities were markedly different from those of the red kidney bean enzyme. A cloning strategy was developed based on N-terminal sequences of the sweet potato and soybean enzymes and short sequences around the conserved metal ligands of the mammalian and red kidney bean enzymes. Three sequences were obtained, one from soybean and two from sweet potato. All three showed extensive sequence identity (>66%) with red kidney bean purple acid phosphatase, and all of the metal ligands were conserved. The combined results establish that these enzymes are binuclear metalloenzymes: Fe-Mn in the sweet potato enzyme and Fe-Zn in soybean. The sweet potato enzyme is the first well-defined example of an Fe-Mn binuclear center in a protein.

Recent advances in the synthesis and applications of 2,6-dipyrazolylpyridine derivatives and their complexes

Abstract: Developments in the chemistry of 2,6-di(pyrazol-1-yl)pyridine (1-bpp) and 2,6-di(pyrazol-3-yl)pyridine (3-bpp), their derivatives and their complexes are surveyed, with emphasis on the last eight years. Particular advances include the synthesis of multi-functional spin-crossover switches; the incorporation of emissive f-element podand centres into biomedical sensors; the self-assembly of a variety of functional soft materials and surface structures; and, the use of 3-bpp complexes in catalysis.

A Review on the Antimicrobial Activity of Schiff Bases: Data Collection and Recent Studies

Abstract: Schiff bases (SBs) have extensive applications in different fields such as analytical, inorganic and organic chemistry. They are used as dyes, catalysts, polymer stabilizers, luminescence chemosensors, catalyzers in the fixation of CO2 biolubricant additives and have been suggested for solar energy applications as well. Further, a wide range of pharmacological and biological applications, such as antimalarial, antiproliferative, analgesic, anti-inflammatory, antiviral, antipyretic, antibacterial and antifungal uses, emphasize the need for SB synthesis. Several SBs conjugated with chitosan have been studied in order to enhance the antibacterial activity of chitosan. Moreover, the use of the nanoparticles of SBs may improve their antimicrobial effects. Herein, we provide an analytical overview of the antibacterial and antifungal properties of SBs and chitosan-based SBs as well as SBs-functionalized nanoparticles. The most relevant and recent literature was reviewed for this purpose.