New Adducts of Triphenylboroxine and Bis-pyridines: Syntheses and Crystal Structures of (Ph3B3O3)(η 1-4,4′-bpy), (Ph3B3O3)2(μ-4,4′-bpy) and (Ph3B3O3)2(μ-bpe)

Abstract

The treatment of phenylboronic acid PhB(OH)2 with 4,4′-bipyridine (4,4′-bpy) in a 3:1 ratio afforded adduct [(Ph3B3O3)(η 1-4,4′-bpy)] (1), whereas the reaction of PhB(OH)2 with 4,4′-bpy in a 6:1 ratio afforded adduct [(Ph3B3O3)2(μ-4,4′-bpy)] (2). Similarly, the reaction of PhB(OH)2 with trans-1,2-bis(4-pyridyl)ethylene (bpe) in a 6:1 ratio gave bpe bridged adduct [(Ph3B3O3)2(μ-bpe)] (3). The crystal structures of 1·½C6H6, 2·2C7H8, 2·C6H14, and 3·C6H6, along with other spectroscopic properties are reported. The weak N···H–C hydrogen-bonds exist in the one-dimensional chains of 1·½C6H6. Treatment of PhB(OH)2 with 4,4′-bpy or bpe under different conditions afforded three new adducts [(Ph3B3O3)(η 1-4,4′-bpy)] (1), [(Ph3B3O3)2(μ-4,4′-bpy)] (2) and [(Ph3B3O3)2(μ-bpe)] (3) through the B–N dative bonds.