Crystal and molecular structure of the six-co-ordinate antimony(III) complex SbCl3,L, where L =N,N′-dimethyloxamide. Unusual O,O ligand binding leading to four-membered Sb(µ-O)2Sb ring formation

Abstract

Antimony trichloride reacts with N,N′-dimethyloxamide (L) to form SbCl₃L. Crystals are triclinic, space group P, Z= 2, with a= 7.492(8), b= 8.954(11), c= 10.544(10)Å, α= 68.1(1), β= 111.0(1), and γ= 111.0(1)°. 1 617 Independent reflections above background were collected on a diffractometer and the structure refined to R 0.065. The unit cell contains two SbCl₃ molecules together with two independent oxamide ligands both with an imposed centre of symmetry. The structure is polymeric with the ligands acting as bridges between SbCl₃ cores. The antimony atom is strongly bonded to three chlorine atoms [2.400(3), 2.387(3), and 2.350(5)Å] and weakly bonded to three oxygen atoms [2.837(9), 2.722(13), and 2.838(8)Å].