Synthesis, characterization, and electronic structures of a methyl germyliumylidene ion and germylone-group VI metal complexes

Abstract

The reaction of germylone (L)Ge (1) [L = 3-Ad-1-{C((t)Bu) = N(Mes)}C3H4N2] with 1 equivalent of MeOTf afforded a germyliumylidene ion [(L)GeMe](+)OTf(-) (2), while reactions with M(CO)5(thf) (M = Cr, Mo, W) gave the corresponding germylone-metal complexes [(L)Ge]M(CO)5 (3-5). The former possesses a pyramidal Ge center, whereas the latter display a planar geometry around the Ge atom. Computational studies showed a unique bonding interaction between 1 and the M(CO)5 unit, which involves a σ-donation as well as a weak π-back-donation.

Tetrylones: An Intriguing Class of Monoatomic Zero‐valent Group 14 Compounds

“…[39] The reactiono fg ermylone 30 with one equivalento fm ethyl trifluoromethanesulfonate (MeOTf) furnished germyliumylidene ion 38 as ared solid in 65 %yield (Scheme 12). [40] The presence of two lone pairs in germylone 30 was confirmedb yt he reaction of 30 with two molar equivalents of MeOTfw hich afforded the corresponding dicationic 39 in 80 % yield. [32] This result exemplifies the nucleophilic properties of 30,i nw hich the germanium atom donates two lone pairs to form two GeÀMe bondsi n39.T he reaction of germylone 30 towardsg roup VI metals have also been investigated.…”

“…The reaction of germylone 30 with one equivalent of methyl trifluoromethanesulfonate (MeOTf) furnished germyliumylidene ion 38 as a red solid in 65 % yield (Scheme ) …”

“…The reaction of germylone 30 towards group VI metals have also been investigated. Treatment of a THF solution of 30 with an equimolar amount of [M(CO) 5 (thf)] (M=Cr–W) at ambient temperature afforded germylone–metal(0) complexes 40 – 42 in moderate yields (Scheme ) . 40 – 42 are stable under an inert atmosphere and readily decompose upon exposure to air.…”

“…The WBI values for the C−N bonds (1.08, 1.23, 1.33) supports the delocalization of the π‐electrons over the [C 2 N 2 Ge] ring. The NPA indicates an overall charge transfer of 0.70 e from the germylone 30 to the Cr(CO) 5 fragment …”

“… Plots of the (a) HOMO of 38 (cation only), (b) HOMO, (c) HOMO−2, and (d) HOMO−9 of 40 , calculated at the B3PW91/3–21G level of theory.…”