Carbene and related complexes of molybdenum derived from electron-rich olefins

Abstract

Reaction of the electron-rich olefin, bis(1,3-dialkylimidazolidinylid-2-ene) (L R 2), with Mo(CO) 6 affords high yields of stable Mo(0) carbonyl complexes containing one or two 1,3 dialkylimidazolidin-2-ylidene (L R) ligands. The Mo-C carb linkage is not readily cleaved by neutral (PR 3) or anionic (X −) ligands. Dihalogens afford carbene-Mo(II) complexes; spectroscopic (IR and 13C NMR) and crystallographic data indicate that their stability is primarily due to the strong Mo-C σ bonds. Other modes of reactivity of L R 2 are demonstrated and the restrictions upon the alkyl (R) group have also been investigated.