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 = CuII or NiII; 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 = Cu^II or Ni^II; 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.