Aminotroponiminatosilathio- and Siloxygermylenes: Reactivity Comparison

Aminotroponiminate (ATI) ligand stabilized
silathiogermylene [(Bui2ATI)­GeSSiMe3] (11) and siloxygermylenes [(Bui2ATI)­GeOSiR3] (R = Me 2, Ph 3) react differently with the same reagents,
i.e., N-methylmorpholine-N-oxide
(nmmo), diironnonacarbonyl,
and elemental sulfur/selenium. Whereas silathiogermylene 11 afforded the first O-silylthionogermaester [(Bui2ATI)­Ge­(S)­OSiMe3] (1) in its reaction with nmmo involving 1,3-silyl
migration, siloxygermylenes 2 and 3 reacted
with the same to give 1,3-dioxadigermetanes [{(Bui2ATI)­Ge­(O)­OSiR3}2] (R = Me 14 and Ph 4, respectively) as
dimerized products. Similarly, in the reaction with diironnonacarbonyl,
compound 3 behaved in the anticipated way and led to
its complex with irontetracarbonyl [(Bui2ATI)­Ge­(Fe­(CO)4)­OSiPh3] (5), but compound 11 did not offer the
desired complex. Further, unlike compound 11, compounds 2 and 3 afford the anticipated O-silylthiono- and selenogermaesters [(Bui2ATI)­Ge­(E)­OSiR3] (E = S; R = Me 1, Ph 7; E = Se; R = Me 6, Ph 8) when treated with elemental sulfur and selenium. As there
is no report on the reactivity of germaesters, the reactions of O-silylthiono- and selenogermaesters 1 and 6–8 are also carried out with methanol
and nmmo.