Synthesis and Characterization of New Phenylbis(salicylato)bismuth(III) Complexes

Compounds with the compositions [BiPh(Hsal)2] (1a) and [BiPh(Hsal4Me)2] (1b) were prepared by the
reactions of triphenylbismuth with 2-hydroxybenzoic acid (H2sal) and 4-methyl-2-hydroxybenzoic acid
(H2sal4Me), respectively, in a 1:2 ratio. The reactions of 1a,b with the bidentate nitrogen donor ligands
1,10-phenanthroline (phen) and 2,2‘-bipyridine (bipy) led to the isolation of the corresponding adducts
[BiPh(Hsal)2(phen)] (2a), [BiPh(Hsal4Me)2(phen)] (2b), [BiPh(Hsal)2(bipy)] (2c), and [BiPh(Hsal4Me)2(bipy)] (2d). Crystallographic analyses of the adducts showed the solids to have monomeric structures
with six-coordinate Bi(III). One salicylato ligand is coordinated in a monodentate fashion and the other
in a bidentate, chelating manner. The phenol oxygen atoms remain uncoordinated in both cases. The
coordination geometry around Bi(III) in 2a, 2b·Me2CO, 2c, and 2d·DMF can be described as distorted
pentagonal pyramidal with an apical C atom, while the free space trans to the ipso carbon atom of the
phenyl group is believed to accommodate a stereochemically active pair of electrons. The 1H data
demonstrate that the salicylate ligands are fluxional in solution. It was shown that under different reaction
conditions a number of bismuth(III) oligomeric, dimeric, and monomeric complexes are produced, including
[Bi38O44(Hsal)26(Me2CO)16(H2O)2]·4Me2CO, [Bi(Hsal4Me)(sal4Me)(phen)]2·2Me2CO ([3]2·2Me2CO),
[Bi(Hsal4Me)3(bipy)]2·4Me2CO ([4]2·4Me2CO), and [Bi(Hsal4Me)3(phen)(MeOH)] (5), which attest to a
rich chemistry in this system.