SYNTHESIS AND STRUCTURE OF 6-COORDINATED ORGANOBISMUTH COMPOUNDS WITHBIDENTATE LIGANDS (12-BI-6)

The thermally stable 12-Bi-6 compound 3-Li+, {(o-C6H4C(CF3)20)2}Bi(p-C H3C6H4)2-Li+, was synthesized. F-19 NMR of 3-Li+ showed a pair of quar tets at room temperature but showed a singlet after addition of 12-cro wn-4 to the solution. The result indicated an important role of the Li + on the structure of the ate complex, and the structure of the Li sal t was assigned as 3A, bearing two cis oxygens, two cis p-tolyl groups, and two trans carbons at ligation sites about the central bismuth ato m. The structure of the ate complex in the presence of 12-crown-4 was assigned as 3C, bearing two cis oxygens, two trans p-tolyl groups, and two cis carbons at ligation sites. Compounds 3 were stable up to 150- degrees-C, but the pair of quartets coalesced at 70-degrees-C and the activation energy of the equilibrium between the CF3 groups was calcul ated to be 18 kcal mol-1 at 70-degrees-C. Bismuth-oxygen bond cleavage followed by pseudorotation was suggested for the coalescence. Compoun ds 3 were inert to electrophilic reagents such as p-(trifluoromethyl) benzoyl chloride. Water reacted with 3 to give an alcohol 17. The alco hol was unstable at room temperature and cyclized with elimination of toluene to afford a 10-Bi-5 (12). Intramolecularly coordinated 12-Bi-6 compounds 18, (o-C6H4C(CF3)20)BiAr2(o-C6H4CR2X) { Ar, R, X: 18a p-CH3 C6H4, CF3, CH3O; 18b p-CF3C6H4, CF3, CH3O; 18c p-CH3C6H4, H, (CH3)2N; 18d p-CF3C6H4, H, (CH3)2N}, were synthesized, three of which were stru cturally determined by X-ray analysis. The structures were all cis geo metry. The synthesis and stability of 12-Bi-6 ate complexes 5, (o-C6H4 C(CF3)20)Bi(P-CH3C6H4)3R-Li+, were also described.