Synthesis, structures, and reactivity of alkylgermanium(II) compounds containing a diketiminato ligand

Reaction of [HC(CMeNAr)(2)]GeCl (Ar = 2,6-iPr(2)C(6)H(3)) with RLi (R = Me, nBu) in diethyl ether at -78 degreesC yielded the alkylgermanium(II) compounds [HC(CMeNAr)(2)]GeR (R = Me (5), nBu (6)), which are monomeric with a three-coordinate germanium center. Compound 5 was oxidized with sulfur and selenium to afford [HC(CMeNAr)(2)]GeMe(E) (E = S (7), Se (8)), in which a terminal Ge=E double bond is present. Treatment of 5 with trimethylsilyl azide in hexane at room temperature gave [HC(C(CH2)NAr)CMeNAr]GeMe(N(H)SiMe3) (9), containing a Ge-N single bond; the expected compound [HC(CMeNAr)(2)]GeMe(NSiMe3) with a Ge=N double bond was not observed. The latter reaction proceeds with migration of a hydrogen atom from a methyl group of the ligand backbone to the nitrogen atom bonded to the silicon atom with formation of a methylene moiety. X-ray structural data are provided for 5, 6, 8, and 9.