Том 45, № 8 (2019)

The rhenium complexes TpReOCl(S^tBu) (I), TpReO(S^tBu)₂ (II), and TpReO(SⁿC₃H₇)₂ (III) are synthesized using two methods by analogy to the known thiophenyl complexes. Complexes I–III having more electron-donating alkylthiolate ligands are characterized by IR and NMR spectroscopy. The structures of complexes I–III are determined by X-ray diffraction analysis (СIF files CCDC nos. 1892096 (I), 1892097 (II), and 1892098 (III)). The temperature dependence of the spectra of the bis(thiolate) complexes allows one to determine the activation energy for the hindered rotation about the Re–thiolate ligand bond. The by-product of the reaction of TpReOCl₂ with NaS-tert-Bu, binuclear oxygen-bridged complex TpRe^IVCl(S-tert-Bu)O(S-tert-Bu)₂Re^IVTp, is isolated and structurally characterized (СIF file CCDC no. 1892099).

Compound 4-(2-methoxyphenyl)-5-(thiophen-2-ylmethyl)-2,4-dihydro-1H-1,2,4-triazole-3-thione (LН) and its complex with cadmium(II) C_42.12H_39.50N₉O_3.12S₆Cl₂Cd (I) are synthesized. Their molecular and crystal structures are determined by X-ray diffraction analysis (СIF files CCDC nos. 1835776 (LН) and 1547251 (I)). Free ligand LН is thione and in the crystal forms H-bonded centrosymmetric dimers by two hydrogen bonds N–H···S. Complex I has a distorted trigonal bipyramidal structure: the sulfur atoms lie in the base and the chlorine atoms occupy the axial positions. Compound LН manifests itself as a monodentate ligand (S) when forming complex I and retains the thione form. The molecule of complex I is stabilized due to strong intramolecular contacts N–H···Cl. The crystal packing of compounds LН and I is formed due to the intermolecular contacts C–H···π, H···S, H···O, and H···N.

The structure of the complex [Cu(Bipy)₂(BA)] ∙ 7H₂O (I), where Bipy is 2,2'-dipyridyl, and BA^2– is the barbituric acid anion (H₂BA), is determined (CIF file CCDC no. 1887338). The thermal decomposition and IR spectrum of complex I are studied. The crystals are orthorhombic: a = 26.118(3), b = 27.685(3), c = 15.683(2) Å, V = 11 370(2) ų, space group Fdd2, Z = 16. The discrete structure of the polar crystal consists of neutral [Cu(Bipy)₂(BA)] particles and molecules of crystallisation water . The Cu²⁺ ion is bound to the N atoms of two bidentate Bipy molecules and the N atom of the BA²⁻ ion at the vertices of the trigonal bipyramid CuN₅. Compound I is the first example of the metal complex only with the N-coordinated anions of barbituric acid (BA²⁻, НBA⁻). The structure is stabilized by hydrogen bonds O−H∙∙∙O and N−H∙∙∙O to form a three-dimensional network with the π–π interaction between the Bipy molecules. The compound begins to lose water at ~50°С and is completely dehydrated above 200°С.

Crystallization of the Ph₃Sb(O₂CCH₂−CH=CH₂)₂ complex upon fast solvent (benzene) evaporation gives monoclinic crystals (I), whereas in the case of slow evaporation, triclinic crystals are formed (II). Also, monoclinic crystals are spontaneously transformed into triclinic crystals within 6 months. It was shown that the presence of voids near one carboxylate ligand in the monoclinic phase of Ph₃Sb-(O₂CCH₂−CH=CH₂)₂ decreases the energy of intermolecular interactions and, as a consequence, leads to a conformational transition with a noticeable decrease in the crystal lattice energy. Thus, the presence of voids in the monoclinic phase crystal allows the formation of a thermodynamically more favorable conformation of the molecule in the crystal. Several structural models were determined for the Ph₃Sb(O₂CCH₂−CH=CH₂)₂ complex (CIF files no. 1887561 (I_IAM), model of non-interacting atoms; 1887562 (I), multipole model; 1887563 (II_IAM), model of non-interacting atoms; 1887564 (II), multipole model).

Two new coordination polymers, {[Cd(Hmph)(Itmb)] ∙ H₂O}_n (I) and [Zn(Hmph)(Bpt)₂]_n (II) (H₂Hmph = homophthalic acid, Itmb = 1-(imidazo-1-yl)-4-(1,2,4-triazole-1-ylmethyl)benzene, Bpt = 3,5-bis(4-pyridyl)-1,2,4-triazole) have been prepared and then characterized by single crystal X-ray diffraction (CIF files CCDC nos. 1842595 (I), 1842591 (II)). Complex I shows a 2D layer structure containing Cd-carboxylate chains linked further by itmb coligands, and the ultimate 3D supramolecular structure is stacked through significant π–π interactions. Complex II displays a zigzag Zn-carboxylate chain structure, which is further extended to the final 3D supramolecular structure by hydrogen-bonding and π–π interactions. TGA experiments indicate that complex I and II have high thermal stabilities because they can maintain framework integrity until 275 and 315°C, respectively. And in comparison, with the free ligands, the fluorescent properties of both CPs show significant blue-shift.