Synthesis, Characterization and Structural Aspects of Three New Nonsymmetrical Bimetallic Dibutyltin (IV) Derivatives

Abstract

Three new nonsymmetric bimetallic diorganotin com- pounds derived from hexadentate Schiff bases were obtained by reac- tion of 2,6-dihydroxybenzene-1,3-dicarbaldehyde with R-(-)-phenyl- glycinol, glycine and 2-amino-5-nitrophenol, in the presence of dibutyltin oxide. The full multinuclear NMR analysis, IR and elemen- tal analyses allowed to establish the structures of all new compounds. In the three cases, the 119 Sn chemical shifts are indicative of two dif- ferent pentacoordinated tin atoms in solution. The molecular structure of compound 4 in the solid state shows two distinct tin atoms with different geometries, one is a distorted trigonal bipyramid with the oxygen atoms in the axial positions and the organic moieties and imine nitrogen in equatorial ones; while the other tin shows distorted octahedral geometry due to Sn(2)-O(4) intermolecular coordination, leading to a dimeric specie, with a Sn-O-Sn-O four-membered ring. The most interesting issue in the solid state is that only one of the tin atoms exhibits intermolecular coordination, in spite of the fact that the atoms are nearly equivalents.