An unexpected transmetalation intermediate: isolation and structural characterization of a solely CH bridged di-copper() complex

Structural characterization of unsupported, two metal centres bridging methyl groups is rare. They have been proposed as transmetalation intermediates in cuprate chemistry, but as yet no structural evidence has been presented. We have isolated a di-copper( i ) complex with solely a methyl ligand bridging two Cu( i ) atoms, representing a new bonding mode of CH 3 . A dicopper( i ) complex, [Cu(PPh 3 ) 2 (μ-Me)CuMe] ( 2 ), in which two metal centres are solely bridged by a methyl group and experience stabilizing metallophilic interactions, has been isolated and structurally characterized, showing a new bonding mode of CH 3 and giving further inside into transmetalation reactions of organocopper compounds.