Synthesis, Structures, and Reactivity of Alkylgermanium(II) Compounds Containing a Diketiminato Ligand

Abstract

Reaction of [HC(CMeNAr)2]GeCl (Ar = 2,6-iPr2C6H3) with RLi (R = Me, nBu) in diethyl ether at −78 °C 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.

Three‐coordinate divalent Group 14 element derivatives and related compounds

“…6 Few solidstate structures of such heteroleptic compounds have been described. Noteworthy examples are in the area of thermodynamic stabilization, the acetylacetonatogermylene R(I)Ge (R = OC(Me)CHC(Me)O) obtained by Stobart 4 in 1979 being the first heteroleptic germylene characterized structurally. One should also mention the germylenes and stannylenes described by Veith et al 6 and Lappert and co-workers 8 46,68 have been particularly involved in this work.…”

“…The bidentate three-atom bridging ligand L 2 (L 2 = PhNC(Me)CHC(Me)NPh), by its remarkable stabilizing properties, allows for easy isolation of subvalent germanium and tin compounds and, as such, permits a general insight on the chemistry of such species. The emphasis here will be on the divalent species L 2 (X)M (M = Ge, Sn), the germanechalcogenones L 2 (Cl)Ge Y, the transitionmetal complexes [L 2 (X)M] x M L (n−x) and the cationic germanium(II)-transition-metal complexes L 2 Ge + W(CO) 5 and L 2 Ge + W(CO) 4 Ge + L 2 (Scheme 1). This work started in 1999, and while it was in progress the preparation and the structures of four other germylated compounds with β-diketiminato ligands bearing a sterically demanding substituent at the nitrogen atoms were reported by Dias and co-workers 1 and Roesky and co-workers.…”

Germacarboxylic Acid: An Organic‐Acid Analogue Based on a Heavier Group 14 Element

“…[3] We have already reported the synthesis and structure of [HC{(CMe)(2,6-iPr 2 C 6 H 3 N)} 2 Ge(S)X] [4] (X = Cl, F, HC{(CMe)(2,6-iPr 2 C 6 H 3 N)} 2 = 2,6-iPr 2 C 6 H 3 NC(CH 3 )CH-C(CH 3 )NC 6 H 3 -2,6-iPr 2 ) with Group 14 and 16 elements bearing a halide. Furthermore, the synthesis and structures of the selenium analogue [HC{(CMe)(2,6-iPr 2 C 6 H 3 N)} 2 Ge-(Se)X] (X = Cl, F), as well as the functionalized derivative [HC{(CMe)(2,6-iPr 2 C 6 H 3 N)} 2 Ge(E)R] (E = S, Se; R = Me nBu) were reported.…”

“…1.914(2) and 95.6(1)8) than in 1. A comparison of the GeÀS bond length in [{h 3 -[(m-tBuN) 2 (SiMetBu) 2 ]}GeS] [12] (2.063(3) ), and in [HC{(CMe)(2,6-iPr 2 C 6 H 3 N)} 2 Ge(S)X] [4] (X = Cl, F), (2.053(6) and 2.050(9) ), with that in 4 (2.077(1) ) shows a good agreement. Likewise, the GeÀO bond length in [(dppe)Pd(m-S)(m- (dppe = bis(diphenylphosphanyl)-ethene) [13] (1.785(6) ), a compound which has almost the same coordination environment and geometry at the germanium center as 4, correlates well with that in 4.…”

Can N-heterocyclic germylenes behave as Lewis acids - is there another side to Meller germylenes?

“…This is probably reflected in the N-Ge bond lengths, the ß-diketiminates have somewhat shorter N-Ge bonds. However, since in all structurally determined molecules of the monoimino germylene type, both N-Ge bond lengths are identical within experimental error [31][32][33][34][35][36][37][38][39][40][41][42], this distinction between coordinative and covalent bonds is unfounded.…”