Iron cyclopentadienylcarbonyl complexes with azoles. I. Complexes of imidazoles and vicinal triazoles

Abstract

The reactions of halides, π-C 5H 5Fe(CO) 2X (X = Cl, Br, I), with sodium salts of some triazoles and imidazoles yield compounds of the composition π-C 5H 5Fe(CO) 2L (L = heterocycle moiety). These complexes react with acids and complex anions in water to form the salts [π-C 5H 5Fe(CO) 2LH] + A − (A − = anion). Stabilization of these salts is ensured by the formation of a hydrogen bond between the cation and anion parts (H-bonding contact ion pair) or between the cation and molecules of the solvent in the outer coordination sphere. The hydrogen bond is realized via the NH group of the heterocyclic ligands and the acceptor fragment of the outer sphere ligands. X-ray analysis of the benzimidazole complex [π-C 5H 5Fe(CO) 21N(C 7H 6N 2)] + B(C 6H 5) − 4·(CH 3) 2O showed that it has monoclinic crystals, a = 13.626(l), b = 25.410(7), c = 10.088(1) Å, β = 92.65(1)°, d exp = 1.28, d calc = 1.285 g/cm 3, Z = 4spatial group P2 1/n. The compounds π-C 5H 5Fe(CO) 2L-B(C 6H 5) 3 have been isolated by decomposition of the salts [π-C 5H 5Fe(CO) 2LH] +A −, where A − = B(C 6H 5) − 4, and LH = some triazoles and imidazoles.