Synthesis of Molybdenum and Tungsten Alkylidene Complexes that Contain a tert-Butylimido Ligand

A variety of molybdenum or tungsten complexes that contain a tert-butylimido ligand have been prepared. For example, the o-methoxybenzylidene complex W(N-t-Bu)(CH-o-MeOC6H4)(Cl)2(py) was prepared through addition of pyridinium chloride to W(N-t-Bu)2(CH2-o-MeOC6H4)2, while Mo(N-t-Bu)(CH-o-MeOC6H4)(ORF)2(t-BuNH2) complexes (ORF = OC6F5 or OC(CF3)3) were prepared through addition of two equivalents of RFOH to Mo(N-t-Bu)2(CH2-o-MeOC6H4)2. An X-ray crystallographic study of Mo(N-t-Bu)(CH-o-MeOC6H4)[OC(CF3)3]2(t-BuNH2) showed that the methoxy oxygen is bound to the metal and that two protons on the tert-butylamine ligand are only a short distance away from one of the CF3 groups on one of the perfluoro-tert-butoxide ligands (H···F = 2.456(17) and 2.467(17) A). Other synthesized tungsten tert-butylimido complexes include W(N-t-Bu)(CH-o-MeOC6H4)(pyr)2(2,2′-bipyridine) (pyr = pyrrolide), W(N-t-Bu)(CH-o-MeOC6H4)(pyr)(OHMT) (OHMT = O-2,6-(mesityl)2C6H3), W(N-t-Bu)(CH-t-Bu)(OHMT)(Cl)(py) (py = pyridine), W(N-t-Bu)(CH-...