SummaryThe products of the reaction of [RhCl (NBD)], (NBD = norbornadiene), with four equivalents tertiary phosphine and two equivalents of tin (11) bromide have been studied by Il9Sn-and ,IP-NMR. spectroscopy. The solution data suggest that halogen scrambling occurs during the preparation and results in a mixture of complexes containing SnBr,, SnClBr,, SnC1,Br and SnCl, ligands, and this is confirmed by independent synthesis of the SnC1, and SnBr, complexes. The metalmetal coupling constants, 1J(L19Sn,1"3Rh), vary from 452 to 580 Hz and are linearly related to: a) 6 ("'Sn) in the complexes [Rh(SnCl,Br(,_.))NBD (PEtPh,),] and b) the sum of the Pauling electronegativities for the halogens on tin.