Syntheses and structures of [Mo(CO) 3(TPA) 3] and [Mo(CO) 3(ETPB) 3]. A structural and spectroscopic correlation

Abstract

Molybdenum tricarbonyl complexes of the type [Mo(CO) 3L 3] (where L = 1,3,5-triaza-7-phosphaadamantane [TPA] or 4-ethyl-2,6,7-trioxa-l-phosphabicyclo-[2.2.2]octane [ETPB] have been synthesized and characterized by IR, 1H, 31P and 95Mo NMR spectroscopies and single crystal X-ray diffraction methods. The X-ray structural determinations are correlated with the observed spectroscopic data. The average MoP bond distance in [Mo(CO) 3(TPA) 3] [2.489(9) Å] is longer than in the corresponding [Mo(CO) 3(ETPB) 3] complex [2.428(5) Å] which is consistent with weaker π-acceptor ability for the cyclic aliphatic TPA ligand compared to the cage phosphite ETPB ligand.