Towards the photodeposition of SixGey-type materials via oligomers of cyclogermapentenes and cyclosilapentenes†

Abstract

This article provides an alternative pathway towards cyclosilapentenes (e.g., SiH₂-ⁱPr and SpiroSi) involving the use of Rieke magnesium to activate the requisite dienes for synthesis. Subsequent metal-mediated dehydrocoupling of cyclosilapentene SiH₂-ⁱPr and mixtures with another cyclogermapentene gives oligomers with backbone Si–Si (number average molecular weight, M_n = 1.0 kDa) and Si–Ge (M_n = 1.4 kDa) linkages, respectively. UV-irradiation (248 nm) of the abovementioned oligotetrelenes and the molecular spirosilane SpiroSi were examined in solution; while evidence for Si_xGe_y-type materials was noted through Raman and EDX spectroscopy, the presence of substantial amorphous carbon as a contaminant was also observed. (TD)-DFT computational studies on the spirosilane SpiroSi provide some insight into the lack of efficient Si_xGe_y photodeposition noted in this study.