Том 45, № 5 (2019)

Biradical mononuclear SQ₂\({\text{ZnL}}_{2}^{4}\) and SQ₂ZnL⁵ complexes, binuclear SQ₂Zn(L³)ZnSQ₂ complex, and coordination polymers (SQ₂ZnL¹⁽²⁾)_n are synthesized by the reactions of bis(3,6-di-tert-butyl-o-benzosemiquinonato)zinc (SQ₂Zn) with the bidentate N-donor ligands (L^1–5) (pyrazine (L¹), 4,4'-dipyridyl (L²), phenazine (L³), 4-cyanopyridine (L⁴), and pyrimidine (L⁵)). The structures of the synthesized compounds are determined by X-ray diffraction analysis (СIF files CCDC nos. 1846558–1846563). The binuclear SQ₂Zn(L³)ZnSQ₂ and mononuclear SQ₂ZnL⁵ complexes contain pentacoordinated metal atoms, whereas zinc in the compounds based on the L^1,2,4 ligands exists in the octahedral environment with the trans-arranged o-semiquinonate ligands. The coordination polymers (SQ₂ZnL¹⁽²⁾)_n are capable of depolymerizing on dissolution in organic solvents. According to the data of measuring the temperature dependence of the magnetic susceptibility, the antiferromagnetic exchange between unpaired electrons of the organic radical anions is observed in crystals of the synthesized compounds.

The structural features of eleven mononuclear octahedral d²-Re(V) monooxo complexes with tridentate chelating (O,S,O and S,O,S) ligands, \(\left[ {{\text{ReO}}\left( {\text{L}_{\text{tri}}^{m}} \right)\left( {\text{L}_{\text{bi}}^{n}} \right)} \right],\)\(\left[ {{\text{ReO}}\left( {\text{L}_{\text{tri}}^{m}} \right){\text{C}}{{{\text{l}}}_{{\text{2}}}}} \right]\), are discussed. The \({\text{Re-O}}{{\left( {\text{L}_{\text{tri}}^{m}} \right)}_{{trans}}}\) bond lengths (except for two cases) were shown to be similar to (or somewhat shorter than), the Re–O(L)_cis or Re–O(ST) bond lengths, which is indicative of the presence of pseudo-dioxo ReO₂ groups with increased bond orders for both trans-arranged Re–O bonds. In the structures of two compounds, the \({\text{Re-O}}{{\left( {\text{L}_{\text{tri}}^{m}} \right)}_{{trans}}}\) bonds are, on average, 0.093 Å longer than the Re–O(ST) bonds, which is consistent with the structural requirements of the trans-effect of a multiply bonded oxo ligand.

Some peculiarities of the effect of enantiomers of the monodentate ligand on the stereoisomerism of the mixed octahedral tetrafluoride complexes of d⁰-transition metals are established by the ¹⁹F{¹Н} and ³¹Р{¹Н} NMR methods for the complex formation of TiF₄ with Ph₂P(O)CH₂CH(OH)Me (L) having the asymmetric carbon atom in the aliphatic hydrocarbon radical and being a racemic mixture of enantiomers in СН₂Сl₂. The compositions of the complexes formed in solutions are determined. The conclusion about the relative stereochemical configuration of the chiral and meso-stereoisomers of the geometric isomers of the TiF₄L₂ octahedral complex is based on an analysis of the ¹⁹F NMR spectra using the heterotropic concept.

It was shown by electronic spectroscopy that the visible absorption spectrum of the polynuclear Cu(II)–Gd(III) metallamacrocyclic complex is pH-sensitive. The intensity of the absorption peak at 577 nm decreases 5-fold as the pH decreases from 6.8 to 3.3 and restores the initial level as the pH increases up to 12.4. On the basis of DFT calculations and analysis of topological electron density characteristics, the spectral changes were attributed to protonation of the glycinehydroximate ligand.

Two pillared layer metal organic frameworks, namely {[Co₃(Btc)₂(Bib)₃(H₂O)₂] · 7H₂O}_n(I) and {[Cd₂(Btc)(Bib)₂(Fma)(H₂O)] · H₂O}_n (II), where H₃Btc is benzene-1,3,5-tricarboxylic acid, Fma is formate anion and Bib is 1,4-bis(1-imidazolyl)benzene, have been successfully synthesized by solvothermal method and structurally characterized by element analysis, IR spectroscopy, as well as single crystal X-ray diffractionand power X-ray diffraction (СIF files CCDC nos. 1829267 (I), 1829266 (II)). In the complexes I and II, the full deprotonated aromatic polycarboxylate take the same coordination mode to bridging four metal ions but result in different 2D network, which are further pillared by bib ligands to form 3D architectures with piont symbol of (4².6⁴)₂(4².6⁷.8)₂(6⁴.8²) and (4².6³.8)(4².6⁴)(4².6⁷.8), respectively. The photoluminescent property of complex II is also reported.