Experimental and ab initio structural study of the ketotin compounds, X 3 SnCR 2 CH 2 COMe: crystal structures of X 3 SnCMe 2 CH 2 COMe (X = Cl and I)

The MeCOCH 2 CMe 2 ligand in X 3 SnCMe 2 CH 2 COMe ( 2 ; X = halide) acts as a C , O ‐chelating group both in the solid state and in non‐coordinating solutions. The intramolecular SnO bond lengths in trigonal bipyramidal 2 (X = Cl and I), as determined by X‐ray crystallography, indicate that the stronger interaction occurs in 2 X = Cl. Comparisons with the SnO bond lengths in the estertin trihalides, X 3 SnCH 2 CH 2 CO 2 R ( 1 ; R = Me), suggest that the latter form stronger chelates than do 2 . In chlorocarbon solution, 2 (X = Cl, I) undergoes exchange reactions, as shown by NMR spectra, to give all possible halide derivatives, ∑(Cl n I 3− n SnCMe 2 CH 2 COMe) ( n = 0–3). Various ab initio calculations on 2 and X 3 SnCH 2 CH 2 COMe ( 3 ) have been carried out. Comparisons of the theoretical and experimental structures of 2 for X = Cl or I are reported. Copyright © 2005 John Wiley & Sons, Ltd.