SYNTHESIS, HALOGENOLYSIS, AND CRYSTAL-STRUCTURE OF HYPERVALENT ORGANOBISMUTH COMPOUNDS (10-BI-5)

The stable 10-Bi-5 compounds (o-C6H4C(CF3)20)BiAr2R(3(Ar,R): 3a,p-CH3CrH4,p-CH3C6H4; 3b, P-CF3C6H4, p-CF3C6H4; 3c, p-FC6H4, p-FC6H4; 3d, p-CH3C6H4, p-CF3C6H4; 3e, p-CF3C6H4, p-CH3C6H4;3f,p-CH3Cr6H4,PhC=C;3g,p-CH3C6H4,Me) were synthesized. The X-ray structures of 3a,fg showed distorted-trigonal-bipyramidal geometries, and the electronegative apical PhC=C ligand of 3f made the apical Bi-O bond (2.243(3) angstrom) shorter than the Bi-O bond of 3a,g (2.323(4) angstrom in 3a and 2.328(7) angstrom in 3g). Halogenolysis of 3 with sulfuryl chloride or pyridinium bromide perbromide gave the five-coordinate bismuth compounds (o-C6H4C(CF3)20)BiArlAr2X (6 (Ar1, Ar2, X): 6a,p-CH3C6H4,p-CH3C6H4,Cl;6b,p-CF3C6H4,p-CF3C6H4,Cl;6c,p-FC6H4, p-FC6H4, Cl; 6d, p-CH3C6H4, p-CH3C6H4, Br; 6e, p-CH3C6H4, p-CF3C6H4, Cl; 6f, p-CH3C6H4, p-CF3C6H4, Br) in good to quantitative yield with apical covalent Bi-halogen bonds which were clearly shown by the X-ray analysis of 6a,b,d,e. The reactivity order of 3 for the halogenolysis was as follows: PhC=C-Bi > Me-Bi > p-CH3CrH4-Bi > p-CF3C6H4-Bi. Direct halogenolysis of the bismuth-carbon bond was suggested. The variable-temperature F-19 NMR of unsymmetrically substituted 6e,f did not show coalescence of the CF3 groups up to 170-degrees-C in a dilute solution of toluene-d8, and the energies of inversion at the bismuth atom should be higher than 21 kcal mol-1 at 170-degrees-C.