Transition metal Schiff-base complexes as ligands in tin chemistry. Part 1. A tin-119 Mössbauer spectroscopic investigation of the adducts SnX₄·ML, SnMe₂(NCS)₂·ML, and SnRCl₃·ML (X = halide; M = Cu^IIor Ni^II; L = quadridentate Schiff-base ligand; R = phenyl or n-butyl)

Abstract

Mössbauer quadrupole splitting data for adducts SnX4·ML, SnRCl3·ML, and SnMe2(NCS)2·ML [R = Ph or Bun, X = Cl, Br, or I; M = CuII or NiII; L =NN′-ethylenebis(salicylideneiminate), NN′-o-phenylenebis(salicylideneiminate), or derivatives of these] are discussed in terms of the point-charge model, and calculated quadrupole splitting data are presented for 27 of the adducts SnRCl3·ML. For each adduct SnRCl3·ML the mer and fac calculated values differ substantially and one is generally in excellent agreement with the experimental value; on this basis geometry is assigned. Examples of mer and fac isomers occur with the former being favoured by the more strongly donating metal Schiff-base complexes. In the case of two complexes it proved possible to isolate both the mer and fac isomers.