Germaester Complexes with a Ge(E)O<i>t</i>-Bu Moiety (E = S or Se)

Although germanium analogues of ketones, carboxylic acids, acid halides, and amides are known, an example of a germaester complex is still missing. Therefore, the first examples of germathioesters [(R)2ATI]­Ge­(S)­Ot-Bu (R = t-Bu 5 and R = i-Bu 6) and germaselenoesters [(R)2ATI]­Ge­(Se)­Ot-Bu (R = t-Bu 7 and R = i-Bu 8) stabilized through aminotroponiminate (ATI) ligands are reported here. Aminotroponiminatogermylene alkoxides [(t-Bu)2ATI]­GeOt-Bu (3) and [(i-Bu)2ATI]­GeOt-Bu (4) serve as starting materials for the synthesis of the aforementioned ester complexes. Compounds 5–8 were characterized by multinuclear NMR spectroscopic and single-crystal X-ray diffraction studies in the liquid and solid state, respectively. 77Se NMR spectra of compounds 7 and 8 showed a singlet resonance at −77.76 and −285.10 ppm, respectively. The germanium center in compounds 5–8 adopts a distorted tetrahedral geometry. The average GeS and GeSe bond lengths in germathioester (5 and 6) and germaselenoester (7 and 8) complexes are 2.078 and 2.219 Å, respectively.