Synthesis, spectroscopy and structure of [N-(2-carboxyphenyl)salicylideneiminato]dimethyltin(IV)

The novel dimethyltin complex with formula Me2Sn(2-OC6H4CH=NC6H4COO), compound 1, involving the Schiff base derived from anthranilic acid and salicylaldehyde, has been synthesized and characterized by elemental analysis, IR,H-1-,C-13- and Sn-117-NMR, Sn-119 Mossbauer spectroscopy and single-crystal X-ray diffraction structure analysis. The crystals of complex 1 are monoclinic, space group P2(1)/n, a = 8.907(5), b = 12.044(7), c = 14.062(9) Angstrom, beta = 104.99(5)degrees, Z = 4, R-1 = 0.0296, R-w(2) = 0 08 for 1368 observed reflections. The crystal structure of 1 features centrosymmetric dimers disposed about a central Sn,Ol core. The tin environment is seven-coordinate if a moderately long contact distance Sn(1)-O(2a) (2.69(1) Angstrom) and a longer one Sn(1)-O(3a) (3.03(1) Angstrom) are included in the coordination list. In the basic monomeric structural unit, the tin configuration can be seen as a distorted square-pyramid with the imine nitrogen atom in apical position, the N-(2-carboxyphenyl)salicylideneimine dianion coordinating a single tin atom via the phenolate oxygen atom, the imine nitrogen atom and one of the carboxylate oxygen atoms. The distortion of the square pyramid is discussed in terms of a trend to trigonal-bipyramidal geometry. (C) 1999 Elsevier Science S.A. All rights reserved.