Строение диоксиматов триарилсурьмы и оценка степени заполнения координационной сферы атома металла

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On the basis of the X-ray diffraction analysis data for a number of triarylantimony dioximates Ar3Sb(ON=CHR)2, comparative description of their molecular structures and evaluation of structural features have been carried out. In the triarylantimony dioximate molecules, the Sb···N intramolecular contacts are observed (2.728(4)–2.900(6) Å), which are sometimes smaller by approximately 1 Å than the sum of the van der Waals radii of the partner atoms (3.61 Å). The shortened Sb···N distance is not accompanied by the expected lengthening of the N–O bonds in the iminoxy group and does not depend on the Sb–O bond lengths. However, the shortening of the Sb···N distances correlates with a decrease in the NOSb bond angle. In structures, containing methoxy groups in aryl ligands at the antimony atom, the intramolecular interactions of the Sb···OMe type are observed. In triarylantimony dioximates, containing different aryl ligands at the antimony atom, but identical oximate ligands, no dependences of the [SbO2C3] coordination unit geometric parameters on the nature of aryl ligands are observed, but in some structures there is a regular elongation of the Sb···N intramolecular distances. For the first time in the Solid-G program for triarylantimony dioximates, the quantitative assessment of the antimony atom coordination sphere occupation degree in the model of ligand solid angles (G-parameter) has been carried out, taking into account the molecular geometry in the crystalline state according to the X-ray diffraction analysis results, which amounts to 80.19–85.70%. The maximum coordination sphere occupation (90.93%) occurs in the structure where the Sb···OMe intramolecular interactions are observed. In bis(μ3-2-oxybenzaldoximato-O,O',N)-(μ2-oxo)-tetraaryl)disantimony, where the 2-hydroxybenzaldoximate ligand is tridentate, it is a bridging one, while the antimony atoms are hexacoordinated, the coordination sphere occupation degree exceeds 90%.