2-[N,N-Bis(trimethylstannyl)amino]pyridine and Bis[N-(N-trimethyIsiIyI- 2-aminopyridyI)]dimethyltin - Intramolecular N-Sn Co-ordination

2-[N,N-Bis(trimethylstannyl)amino]pyridine (1), bis[N-(N-trimethylsilyl-2-aminopyridyl)]- dimethyltin (2) and bis[N-(N-trimethylsilyl-2-amino-3-methyl-pyridyl)]dimethyltin (3) were prepared and characterized by 1H, 13C, l5N, 29Si and 119Sn NMR spectroscopy. In the case of 1, intramolecular pyridine-N-Sn co-ordination was established by the low temperature 119Sn NMR spectra which show two resonance signals, one for a penta-co-ordinate and one for a tetra-co-ordinate tin site. In the cases of 2 and 3, intramolecular pyridine-N-Sn co-ordination follows conclusively from 13C, 15N and 119Sn NMR parameters. In contrast with the known behaviour of the corresponding trimethyltin derivative, the methyl group in 3-position of the pyridine ring does not prevent this type of co-ordination in 3.