Synthesis and metal complexes of a tertiary phosphine, 2-(2-(diphenylphosphaneyl)-1H-imidazol-1-yl)pyridine containing pyridyl and imidazole moieties

Abstract

A tertiary phosphine, [2-{PPh2C3H2N2}C5H4N] (2), containing both imidazole and pyridine moieties was synthesized by the reaction of 2-(1H-imidazol-1-yl)pyridine (1) with nBuLi followed by the addition of PPh2Cl. Reactions of 2 with group 6 metal carbonyls and group 10 metal salts resulted in chelate complexes [{2-{PPh2C3H2N2}C5H4N}{M(CO)4}] (3, M = Mo; 4, M = W) and [{2-{PPh2C3H2N2}C5H4N}{MCl2}] (5, M = Pd; 6, M = Pt). However, 1:1 reactions of 2 with CuX (X = Cl, Br, I) yielded dinuclear complexes [{2-{PPh2C3H2N2}C5H4N}{CuX}]2 (7, X = Cl; 8, X = Br; 9, X = I) containing [Cu(μ-X)]2 rhombus units, whereas the reaction between 2 and [Cu(NCMe)4]BF4 produced a spirocyclic complex, [{2-{PPh2C3H2N2}C5H4N}2Cu]BF4 (10). The molecular structures of complexes 4, 6 and 8 were determined using X-ray diffraction studies. Upon coordination, the bite angle of the ligand varies from 78.76(6)° (4) to 96.16(2)° (8) due to inherent flexibility associated with the ligand framework as well as the geometries preferred by the metal atoms.