Hypervalent Pentafluoroethylgermanium Compounds, [(C F ) GeX ] and [(C F ) GeF ] (X=F, Cl; n=2-5).

This paper gives an account on hypervalent fluoro- and chloro(pentafluoroethyl)germanium compounds. The selective synthesis of the tris(pentafluoroethyl)dichlorogermanate salt [PNP][(C F ) GeCl ] as well as its X-ray structural analysis is described. As a representative example for pentafluoroethylfluorogermanates, the synthesis and structure of 2,4,6-triphenylpyryliumtris(pentafluoroethyl)difluorogermanate [C H O][(C F ) GeF ] is reported. Fluoride-ion affinities for pentafluoroethylgermanes were calculated using quantum chemical methods, disclosing (C F ) GeF as a weaker Lewis acid than (C F ) SiF or (C F ) PF . The theoretical results were confirmed by experiments and give the basis of a synthetic protocol for (C F ) GeF. Pentakis(pentafluoroethyl)germanate [PPh ][Ge(C F ) ] was detected as an intermediate during the synthesis of [PPh ][(C F ) GeF] starting from tris(pentafluoroethyl)difluorogermanate and LiC F .