Diaminogermylene and Diaminostannylene Derivatives of Gold(I): Novel AuM and AuM2 (M = Ge, Sn) Complexes

The reactions of [AuCl­(THT)] (THT = tetrahydrothiophene) with 1 equiv of the group 14 diaminometalenes M­(HMDS)2 [M = Ge, Sn; HMDS = N­(SiMe3)2] lead to [Au­{MCl­(HMDS)2}­(THT)] [M = Ge (1), Sn (2)], which contain a metalate­(II) ligand that arises from insertion of the corresponding M­(HMDS)2 reagent into the Au–Cl bond of the gold­(I) reagent. While compound 1 reacts with more Ge­(HMDS)2 to give the germanate–germylene derivative [Au­{GeCl­(HMDS)2}­{Ge­(HMDS)2}] (3), which results from substitution of Ge­(HMDS)2 for the THT ligand of 1, an analogous treatment of compound 2 with Sn­(HMDS)2 gives the stannate–stannylene derivative [Au­{SnCl­(HMDS)2}­{Sn­(HMDS)2(THT)}] (4), which has a THT ligand attached to the stannylene tin atom and which, in solution at room temperature, participates in a dynamic process that makes its two Sn­(HMDS)2 fragments equivalent (on the NMR time scale). A similar dynamic process has not been observed for the AuGe2 compound 3 or for the AuSn2 derivatives [Au­{SnR­(HMDS)2}­{Sn­(HMDS)2(THT)}] [R = Bu (5), HMDS (6)], which have been prepared by treating complex 4 with LiR. The structures of compounds 1 and 3–6 have been determined by X-ray diffraction.