Synthesis and structural study of organoantimony(III) and organobismuth(III) triflates and cations containing O,C,O-pincer type ligands

The reactions of intramolecularly coordinated organoantimony and organobismuth dihalides (LSbCl2)-Sb-1 and (LBiCl2)-Bi-2, containing two types of O,C,O-pincer ligands 2,6-(ROCH2)C6H3- (L-1, R = Me; L-2, R = Bu-t), with silver salts of the weakly nucleophilic polar groups CF3SO3- (OTf) and CB11H12- (in 1:1 and 1:2 molar ratios) gave the following compounds: (LSbCl)-Sb-1(OTf) (1), (LBiCl)-Bi-2(OTf) (2), (LSb)-Sb-1(OTf)(2) (3), (LBi)-Bi-2(OTf)(2) (4), (LSbCl)-Sb-1(CB11H12) (5), (LBiCl)-Bi-2(CB11H12) (6). All compounds were characterized structurally by X-ray diffraction. In the solid state, compounds 1-3 have OTf groups covalently (although weakly) bound to the central metal atom. In compound 4, one of the OTf groups is bound in a unidentate fashion and the other in a weakly chelating fashion. Compounds 5 and 6 exist as separated ion pairs consisting of a [(LSbCl)-Sb-1(THF)](+) or [(LBiCl)-Bi-2](+) cation and CB11H12- anion. The donor oxygen atoms are coordinated to the metal atoms through strong intramolecular interactions in all compounds. The solution structures of all compounds were studied by the help of variable-temperature H-1 NMR measurements.