Super Bulky Bismuth(III) Imidazole Selones: Structural and Bonding Aspects

Treatment of BiBr 3 with super bulky [(IPaul)Se] ( L 1 ) ([(IPaul)Se] = 1,3-bis(2,4-methyl-6-diphenyl phenyl)imidazole selone) or IPr*Se ( L 2 ) (IPr*Se = 1,3-bis(2,6-diphenylmethylphenyl)imidazole selone) in toluene afforded the dinuclear complex [( L 1 )BiBr 2 ( µ -Br)] 2 ( 1 ) and mononuclear complex [( L 2 )BiBr 3 ] ( 2 ), whose structures have been determined by an X-ray crystallographic study. The products were characterized by a combination of 1 H NMR and 13 C NMR spectroscopy. The thermal stability of 1 and 2 was compared using TGA. These steric and electronic factors controlled super bulky ligand systems allow for the first structural isolation of a novel super bulky dinuclear complex 1 with edge shard octahedral geometry and mononuclear super bulky complex 2 with mono capped seesaw geometry. The sterically more crowded complex 2 showed the long Bi-Se bond distance (3.192(3) Å) compared to 1 (2.902(5) Å).