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)TiC^tBu (A) (PNP⁻ = N[2-P(CHMe₂)₂-4-methylphenyl]₂), can cleanly activate methane at room temperature with moderately elevated pressures to form (PNP)TiCH^tBu(CH₃). Isotopic labeling and theoretical studies suggest that the alkylidene and methyl hydrogens exchange, either viatautomerization invoking a methylidene complex, (PNP)TiCH₂(CH₂^tBu), or by forming the methane adduct (PNP)TiC^tBu(CH₄). The thermal, fluxional and chemical behavior of (PNP)TiCH^tBu(CH₃) is also presented in this study.