Cyano-bridged polynuclear coordination compounds derived from paramagnetic [Mn(H2daptsc)]2+ and photochromic [Fe(CN)5NO]2− building blocks

Metal complexes with H2daptsc ligand were first used as building blocks to create polynuclear multifunctional materials.

Zn(II) and Ag(I) complexes of N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids and products their proton- and iodocyclization

The possibility of using N-allylcarbothioamide derivatives as well as products of their iodine- and proton-initiated electrophilic heterocyclizations as chelating agents in complexation reactions with Zn(II) and Ag(I) ions is shown. Processing of the obtained experimental data showed that N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids H2L1 – H2L3 and their proton- and iodo-cyclization products HL4, HL5 containing four nucleophilic reaction centers (two oxygen atoms of the carbonyl and hydroxyl groups and N-, S-carbothioamide groups or N-atoms of the dihydrothiazole moiety) are polydentate ligands capable of coordinating with metal ions to form stable six-membered chelate metallocycles. A series of new chelating mono-, bi- and polynuclear complexes Zn(II) and Ag (I) of the composition [Zn2L1,32]n, [Zn2(HL1-3)2(CH3COO)2], [Ag2(HL1,3)2]n, [Zn(HL1-3)2], [Ag(H2L3)2NO3], [Zn(HL4,5)2], K[Ag(HL4,5)2] were synthesized and isolated in solid state. Their molecular structure was established by methods of elemental chemical analysis, NMR 1H, IR and UV-Vis spectroscopy. At a ratio of M:L 1:2, complexes were isolated in which two ligand molecules H2L1 − H2L3 are coordinated to the metal ion by the sulfur atoms of the carbothioamide group and the oxygen of the mono-deprotonated hydroxyl group. It was established that the products of the proton-/iodocyclization HL4, HL5 in the complex formation pass into the thione tautomeric form with coordination through the oxygen atoms of the deprotonated hydroxyl group and nitrogen atoms of the dihydrothiazole heterocycle. At M:L 1:1, binuclear or polynuclear coordination compounds are formed. It was shown that polymerisation in complexes [Zn2L1,32]n and [Ag2(HL1,3)2]n is due to the formation of Zn−(O2SN)−Zn and Ag−O−Ag polymer chains. Investigation of the solubility of the resulting complexes showed that the polymer complexes are weakly soluble or insoluble in DMSO, DMF, while the mononuclear are soluble in methanol, as well as in water.

Zn(II) and Ag(I) complexes of N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids and products their proton- and iodocyclization

The possibility of using N-allylcarbothioamide derivatives as well as products of their iodine- and proton-initiated electrophilic heterocyclizations as chelating agents in complexation reactions with Zn(II) and Ag(I) ions is shown. Processing of the obtained experimental data showed that N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids H2L1 – H2L3 and their proton- and iodo-cyclization products HL4, HL5 containing four nucleophilic reaction centers (two oxygen atoms of the carbonyl and hydroxyl groups and N-, S-carbothioamide groups or N-atoms of the dihydrothiazole moiety) are polydentate ligands capable of coordinating with metal ions to form stable six-membered chelate metallocycles. A series of new chelating mono-, bi- and polynuclear complexes Zn(II) and Ag (I) of the composition [Zn2L1,32]n, [Zn2(HL1-3)2(CH3COO)2], [Ag2(HL1,3)2]n, [Zn(HL1-3)2], [Ag(H2L3)2NO3], [Zn(HL4,5)2], K[Ag(HL4,5)2] were synthesized and isolated in solid state. Their molecular structure was established by methods of elemental chemical analysis, NMR 1H, IR and UV-Vis spectroscopy. At a ratio of M:L 1:2, complexes were isolated in which two ligand molecules H2L1 − H2L3 are coordinated to the metal ion by the sulfur atoms of the carbothioamide group and the oxygen of the mono-deprotonated hydroxyl group. It was established that the products of the proton-/iodocyclization HL4, HL5 in the complex formation pass into the thione tautomeric form with coordination through the oxygen atoms of the deprotonated hydroxyl group and nitrogen atoms of the dihydrothiazole heterocycle. At M:L 1:1, binuclear or polynuclear coordination compounds are formed. It was shown that polymerisation in complexes [Zn2L1,32]n and [Ag2(HL1,3)2]n is due to the formation of Zn−(O2SN)−Zn and Ag−O−Ag polymer chains. Investigation of the solubility of the resulting complexes showed that the polymer complexes are weakly soluble or insoluble in DMSO, DMF, while the mononuclear are soluble in methanol, as well as in water.

Bi- and polynuclear coordination compounds of d-elements as catalysts of homogeneous selective oxidation of thiol groups

This research aims to study the catalytic cycle reactions for homogeneous selective oxidation of thiol RSH groups to RSSR with the participation of coordination compounds for d-element ions-NiII, PdII, Pt II, CuI , CuII. We used the DFT M06, PBE0 / Def2-TZVP methods to build the quantum chemical models of the reactions. We have developed a mechanism for the functioning of the catalytic system in which primary active centers are either binuclear {M(-OH)2M}n+ or polynuclear {M(μ-OH)2M(μ-OH)2M}2+ sites. Catalysts under consideration should retain stable spatial complementarity at all stages of the process. The main interrelated functions of the binuclear catalysts are the spatial approaching of anions RS– in the inner sphere of the bridged coordination compound required for the disulfide (–S–S–) cross-linking and the two-electron redox transfer during the transformation of these anions into disulfide (СH3)2S2

Case Studies in the Challenge of Properties Design at Nanoscale

In the quest for nano-sized materials with potential applications in new technologies and devices, the molecular magnetism based on coordination systems shows a valuable path, including the idea of structure-property rationales. Polynuclear coordination compounds are already in the range of nanometers and many consecrated magnetic materials that can be prepared at nano-scale granulation, such as oxides, have as bonding and exchange coupling mechanisms the same causal engines identified in coordination systems. Based on this paradigm, several case studies are taken, relating the magnetic properties with methods of electron structure calculations and phenomenological models.

Synthesis of Y3Fe5O12 via Thermal Decomposition of Polynuclear Coordination Compounds

The possibility of obtaining yttrium iron garnet (Y3Fe5O12, YIG) through thermal decomposition of two coordination compounds with malate and gluconate anions as ligands, (NH4)6[Y3Fe5(C4O5H4)6(C4O5H3)6]·12H2O and (NH4)6[Y3Fe5(C6O7H10)6(C6O7H9)6]·8H2O. A mixture of simple oxides, namely Y2O3 and α-Fe2O3, orthorhombic ferrite YFeO3 and small amounts Y3Fe5O12, is generated from the thermolysis of malate compound, while a clean Y3Fe5O12 is obtained from gluconate compound.