Hypercoordination in triorganoantimony(III) compounds. Case study of heteroleptic [2,6-(Me2NCH2)2C6H3]2(Ph)Sb

The triorganoantimony(III) compound [2,6-(Me2NCH2)2C6H3]2(Ph)Sb (1), containing three aryl groups, two of them with two pendant arms capable for N→Sb intramolecular interactions, was prepared and structurally investigated, both in solution and in solid state. The 1H and the 13C NMR spectra suggested no intramolecular N→Sb interaction. The molecular structure was determined by single-crystal X-ray diffraction and revealed a N,C,N-tridentate coordination of one 2,6-(Me2NCH2)2C6H3 group, while the other one displayed only a C,N-bidentate coordination behaviour towards antimony. The coordination environment about antimony is a highly distorted octahedron, and the compound can be described as a 14Sb6 hypercoordinate species.