Vol 45, No 9 (2019)

New stannylene ^AdAPSn (I) based on 4,6-di-tert-butyl-N-adamantyl-o-aminophenol is synthesized and structurally characterized. Stannylene I in the crystalline state forms infinite chains due to intermolecular donor–acceptor Sn–N and metallophilic Sn···Sn interactions. The reactivities of compound I and earlier synthesized ^t-BuAPSn (II) are studied using their redox and acid–base reactions. Stannylenes I and II are inserted at the S–S bond of tetramethylthiuram disulfide to form the corresponding tin(IV) dithiocarbamate complexes. The reactions with soft one-electron oxidants involve the redox-active o-amidophenolate ligand and generate labile paramagnetic stannylenes studied by EPR spectroscopy. The presence of a lone electron pair at the low-valence tin atom is a reason for its basic properties, which is demonstrated for the reaction of compound I with nanocarbonyl iron. The structures of selected synthesized compounds are determined by X-ray diffraction analysis (СIF files CCDC nos. 1905419–1905421).

A series of heterospin bis-o-semiquinone cobalt, nickel, and copper complexes (4-TEMPO-oxy-3,6-di-tert-butyl-o-benzoquinone derivatives) is synthesized: (DMSO)Cu(4-TEMPO-O-3,6-DBSQ)₂ (I), (THF)₂Ni(4-TEMPO-O-3,6-DBSQ)₂ (II), (Py)₂Ni(4-TEMPO-O-3,6-DBSQ)₂ (III), and (Py)₂Ni(4-TEMPO-O-3,6-DBSQ)₂ (IV) (4-TEMPO-O-3,6-DBQ is 4-(3,6-di-tert-butyl-1,2-dioxocyclohexa-3,5-dien-4-yloxy)-2,2,6,6-tetramethylpiperidine-1-oxyl 4-oxy-2,2',6,6'-tetramethylpiperidine-1-oxyl). All complexes are characterized by elemental analysis, IR spectroscopy, magnetochemistry, and EPR. The structure of complex I is determined by X-ray diffraction analysis (CIF file CCDC no. 1882878). The coordination polyhedron of the copper atom in the molecular structure of the Cu(II) bis-o-semiquinone complex with dimethyl sulfoxide (DMSO) is a distorted tetragonal pyramid, whose equatorial plane contains the o-semiquinone ligands, and the DMSO molecule occupies the apical position. The magnetic properties of complexes I–IV are consistent with their compositions and structures. The magnetic behavior of copper complex I and nickel complexes II and III is determined by the balance of two contributions: metal–ligand ferromagnetic exchange interaction and ligand–ligand antiferromagnetic interaction. The temperature dependence of the magnetic moment of cobalt complex IV shows the redox isomeric transformation conjugated with the spin transition, which is characteristic of complexes of this type. No participation of nitroxyl radical centers is observed in intermolecular coordination.

The complex formation of TiF₄ with the phosphorylated ketone Ph₂P(O)CH(Me)CH₂C(O)Et (L), containing an asymmetric carbon atom in the aliphatic hydrocarbon group and representing a racemic mixture of enantiomers, was studied by ¹⁹F{¹H} and ³¹P{¹H} NMR spectroscopy. The composition of complexes formed in the solution was determined; analysis of the ¹⁹F NMR spectra resorting to the heterotropicity concept was used to assign the resonance lines to two chiral optically active racemic and meso-stereoisomers of cis-TiF₄L₂. The configurations of enantiomers of the monodentate ligand coexisting in the coordination sphere were found to have a crucial effect on the axial fluorine atoms of mixed octahedral cis-tetrafluoro d⁰ transition metal complexes. A new efficient method was developed for the synthesis of ligand L.