TRANSITION-METAL SCHIFF-BASE COMPLEXES AS LIGANDS IN TIN CHEMISTRY .2. A SN-119 MOSSBAUER SPECTROSCOPIC INVESTIGATION OF THE ADDUCTS SNBUNXCL3-X(OR)BULLET-ML (X=O OR 1, R=H OR ALKYL, M=CU(II) OR NI(II), L = QUADRIDENTATE SCHIFF-BASE LIGAND)

The compound SnCl3(OEt).EtOH reacts with the complexes ML [M = Cu(II) or Ni(II.), H2L = N,N'-ethylenebis(salicylideneimine), N.N'-o-phenylenebis(salicylideneimine), or derivatives of these] to give the adducts SnCl3(OEt).ML. Hydrolysis of the ethoxo adducts in chloroform under ambient conditions yields the adducts SnCl3(OH).ML. Chloroform solutions of the adducts SnCl4.ML gives similar hydroxo adducts under ambient conditions when M = Cu(II) but not when M = N(II). The compound SnBu(n)Cl2(OH).H2O reacts with ML at -10-degrees-C to give 1:1 adducts, but at higher temperatures SnBu(n)Cl(OH)2.H2O and SnBu(n)Cl3.ML are formed. The compound SnBu(n)Cl2(OMe).MeOH reacts with ML in chloroform to yield the adducts SnBu(n)Cl2(OMe).ML. The replacement of chloride by hydroxide or alkoxide in either SnBu(n)Cl3 or SnCl4 results in a reduction of the Lewis acidity at tin. Mossbauer quadrupole-splitting data for SnBu(n)Cl2(OH).ML and SnBu(n)Cl2(OMe).ML were analysed in terms of the point-charge model from which it was established that the donor oxygen and carbon atoms practically always adopt fac geometry about tin; this contrasts with the mer geometry preferred by many adducts SnBu(n)Cl3.ML.