SN-119 NMR-STUDY OF ORGANOTIN COMPOUNDS HAVING INTRAMOLECULAR SN - N COORDINATION

Sn-119 NMR data are reported for organotin compounds containing potentially C,N-chelating ligands capable of forming five- or six-membered chelate rings. The Sn-119 chemical shifts of divalent organotin compounds containing such a ligand are found at relatively high frequency. Intramolecular coordination in tetraorganotin compounds has little influence on their Sn-119 chemical shifts. However, additional coordination in tri- and di-organotin halides causes a large shift to lower frequency of about 100 ppm. Finally, for organotin compounds which exist as a diastereoisomeric mixture in solution, two well resolved Sn-119 resonances are observed.