STUDIES IN ARYLTIN CHEMISTRY .12. VIBRATIONAL-SPECTRA OF SOME P-TOLYLTIN COMPOUNDS

Raman and infrared spectra of Ar4Sn and Ar(3)SnZ (Z = Cl, Br, I) in th e range 1600-100 cm(-1), and of the adducts Ar(3)SnZ . L (L = HMPA (he xamethylphosphoramide), Z = Cl, Br, I; L = Ph(3)PO (triyphenylphosphin e oxide), Z = Cl, Br) as well as the anions Ar(3)SnZ(2)(-) (Z = CI, Br ) - as tetraethylammonium salts - in the range 400-100 cm(-1) where Ar = p-CH3C6H4, are reported and assignments made for both ring and skel etal modes. Comparison with previous data for the phenyl- and p-fluoro phenyltin analogues shows that replacing hydrogen in the para-position by fluorine or methyl causes nearly the same decreases in v(s)(SnC) a nd v(a8)(SnC), attributed to a simple mass effect, as are the small ch anges noted for (Sn-Z) of Ar(3)SnZ. In contrast the same sequence of s ubstituent changes for the five coordinate systems causes variations i n axial stretching mode frequencies which suggest electronic effects a re significant. The changes correlate with the sigma(p)(+) parameter a nd are rationalised in terms of qualitative molecular orbital energy l evel diagrams for these systems.