High-valent organomanganese chemistry. 1. Synthesis and characterization of manganese(III) and -(IV) alkyls

Abstract

A new manganese(IV) alkyl, the hexamethylmanganate salt [Li(tmed)] 2 [MnMe 6 ], has been prepared by treatment of MnMe 4 (PMe 3 ) 2 with methyllithium followed by addition of N,N,N',N'-tetramethylethylenediamine (tmed). Addition of excess methyllithium to Mn(acac) 3 followed by treatment with tmed gives the pentamethylmanganate [Li(tmed)] 2 [MnMe 5 ]. This trivalent species can also be obtained by a comproportionation reaction of the manganese(IV) complex [Li(tmed)] 2 [MnMe 6 ] with 1 equiv of the manganese(II) complex [Li(tmed)] 2 [MnMe 4 ] in diethyl ether. X-ray crystal structures of [Li(tmed) 2 ][MnMe 4 ] and [Li(tmed)] 2 [MnMe 6 ]