Epoxy Nanocomposites with Metal-Containing Fillers: Synthesis,Structure, and Properties

Russian Journal of Applied Chemistry - Recent achievements in the field of the development of preparation methods and study of structure and properties of epoxy nanocomposites with metal-containing...     

1-amino-2-thiobenzimidazoleimines as novel ambidentate ligand systems

Azomethine derivatives of 1-amino-2-thiobenzimidazole (H₂L) were synthesized and studied by IR and ¹H NMR spectroscopy. Thiobenzimidazoline tautomeric form of these compounds was found to predominate in a solid state and DMSO solution. Novel mono-and binuclear metal chelates M(HL)₂ and M₂L₂ (M = Ni(II), Cu(II), Co(II), Zn(II), Cd(II)) were synthesized on the basis of H₂L derivatives and their composition and structures were established from IR, ¹H NMR, EXAFS, and magnetochemical data. The composition of coordination sphere was shown to produce no effect on ferromagnetic exchange in binuclear Cu(II) complexes.     

Metal-containing monomers. Part 1. Spatial and electronic structures of cobalt(II) and nickel(II) complexes with acrylamide and of their polymers

Summary The spatial and electronic structures of the complexes [Co(AAm)₄(H₂O)₂](NO₃)₂ (1), Co(AAm)₄Cl₂ (2), [Ni(AAm)₄(H₂O)₂](NO₃)₂ (3) and Ni(AAm)₄Cl₂ (4), where AAm is acrylamide, and the products of their radical, frontal and post-grafting polymerization have been studied by electronic spectroscopy. The complexes (1), (3) and (4) were found to have pseudooctahedral structures in both the solid and solution phases. A change in the spatial structure of complex (2) was established in going from the crystal (tetragonally distorted octahedral) to solution (tetrahedral). The coordination environment of the metal centre does not change markedly during polymerization of the metal-containing monomers.     

Synthesis and reactivity of metal-containing monomers

Acid and neutral Co^II, Cu^II, Ni^II, Zn^II, Fe^II, and Fe^III maleates, fumarates, and itaconates were obtained and characterized. The methods for their synthesis were optimized, and the valence state and coordination of metals were studied. Co^II and Fe^II hydrogen maleates, Co^II maleate, and Co^II fumarate were examined by X-ray diffraction analysis. The ligands based on unsaturated dicarboxylic acids can be mono-, bi-, and tetradentate, which results in the formation of acid salts, chain and three-dimensional coordination polymers, whose double bond is not involved in the coordination. The strong antiferromagnetic exchange (μ_elf=1.41 and 0.34 μ_B at 290 and 80 K, respectively) was detected in Cu^II itaconate. Based on the data of Mössbauer spectroscopy, the partial reduction of Fe^III to Fe^II during the synthesis of Fe^III maleate was shown to occur: δFe=0.43 and 1.27 mm s^?1, ΔE _Q=0.57 and 3.13 mm s^?1 and Γ=0.37 and 0.28 mm s^?1 atT=298 K for Fe^III and Fe^II, respectively.     

Synthesis and structure of 2,2′-diaminodiphenylditelluride bis-imines

Bis-imines of 2,2′-diaminodiphenylditelluride and 2-tosylamino (9a) and 2-hydroxybenzaldehyde (9b) were prepared and studied by X-ray diffraction, heteronuclear (¹H, ¹³C, ¹⁵N, and ¹²⁵Te) magnetic resonance, and quantum chemical calculations (Pbe1pbe/DGDZVP). According to the X-ray diffraction data, compound 9b in the crystal phase has nonsymmetrical structure: one of the tellurium atoms forms hypervalent bonding with the adjacent oxygen atom, while the second one is not involved in such interaction. The NMR study showed the symmetric molecular structure of imines 9a,b in DMSO-d₆ with the tellurium atoms interacting hypervalently with the C=N nitrogen atoms.     

New Ambidentate Ligands—Azomethin Derivatives of 1-Amino-3-methylbenzimidazoline-2-thion

Metal chelates ML₂ (M = Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺) are synthesized from azomethin derivative of amino-3-methyl-benzimidazoline-2-thion and 2-N-tosylaminobenzaldehyde (HL) and their compositions and structures are determined from the electronic mass spectrometry, IR and electronic spectroscopy and magnetochemistry data.     

Nanocomposites of Graphene Oxide and Metal-Organic Frameworks

Russian Journal of Applied Chemistry - The state of the art in the field of preparing nanocomposites of graphene oxide with metal-organic frameworks and of studying their structure and properties...     

Polymer-Immobilized Clusters and Metal Nanoparticles in Catalysis

Kinetics and Catalysis - Recent advances in the synthesis of polymer-immobilized clusters and metal nanoparticles and their use in catalysis of many organic reactions were presented. The main types...