Methane activation and exchange by titanium-carbon multiple bonds

Abstract

We demonstrate that a titanium-carbon multiple bond, specifically an alkylidyne ligand in the transient complex, (PNP) Ti equivalent to(CBu)-Bu-t (A) (PNP- = N[2-P(CHMe2)(2)-4-methylphenyl](2)), can cleanly activate methane at room temperature with moderately elevated pressures to form (PNP)Ti=(CHBu)-Bu-t(CH3). Isotopic labeling and theoretical studies suggest that the alkylidene and methyl hydrogens exchange, either via tautomerization invoking a methylidene complex, (PNP)Ti=CH2((CH2Bu)-Bu-t), or by forming the methane adduct (PNP)Ti equivalent to(CBu)-Bu-t(CH4). The thermal, fluxional and chemical behavior of (PNP)Ti=(CHBu)-Bu-t(CH3) is also presented in this study.