Synthesis and reactivity of germyl complexes of manganese and rhenium

Trichlorogermyl complexes M(GeCl3)(CO)nP5− n (1–4) [M = Mn, Re; n = 2, 3; P = PPh(OEt)2 (a), P(OEt)3 (b)] were prepared by allowing chloro compounds MCl(CO)nP5− n to react with an excess of GeCl2•dioxane in 1,2-dichloroethane. Treatment of compounds 1–4 with LiAlH4 in thf yielded trihydridegermyl derivatives M(GeH3)(CO)nP5−n (5–8), whereas treatment of the same complexes with NaBH4 in ethanol afforded triethoxygermyl derivatives M[Ge(OEt)3](CO)nP5−n (9–11). Trimethylgermyl compounds M(GeMe3)(CO)nP5−n (12, 13) and the alkynylgermyl derivative Mn[Ge(CCPh)3](CO)3[PPh(OEt)2]2 (14a) were also prepared by allowing trichlorogermyl compounds 1–4 to react with either MgBrMe or Li+CCPh−, respectively, in thf. Treatment of compound Re(GeCl3)(CO)3[PPh(OEt)2]2 (4a) with SnCl2•2H2O gave the stannyl-germyl derivative Re[GeCl2(SnCl3)](CO)3[PPh(OEt)2]2 (15a). The complexes were characterised by spectroscopy and X-ray crystal structure determination of 4a, 5a, and 13a.

Graphical abstractThe preparation of trichlorogermyl complexes M(GeCl3)(CO)nP5−n of manganese and rhenium by reaction of chloro precursors with GeCl2•dioxane is described. Treatment of trichlorogermyl complexes with LiAlH4 leads to trihydridegermyl derivatives M(GeH3)(CO)nP5−n, whereas reaction with NaBH4 yields triethoxygermyl compounds M[Ge(OEt)3](CO)nP5−n. Organogermyl derivatives M(GeMe3)(CO)nP5−n and M[Ge(CCPh)3](CO)nP5−n were also prepared by substituting chlorides in [M]–GeCl3 with Grignard reagent MgBrMe and lithium acetylide Li+CCPh–, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Synthesis of trichlorogermyl complexes of manganese and osmium. ► Reaction with LiAlH4 leads to trihydridegermyl derivatives. ► Treatment with NaBH4 affords triethoxygermyl complexes. ► Trimethylgermyl and trialkynylgermyl Mn and Re derivatives were also prepared.