Synthesis of Cationic Germyleneiron Complexes and X-ray Structure of [Cp*(CO)₂FeGeMe₂·DMAP]BPh₄·CH₃CN (Cp* = C₅Me₅, DMAP = 4-(Dimethylamino)pyridine)

Abstract

Chlorogermyliron complexes Cp*(CO)2FeGeMe2Cl (1) and Cp*(CO)(PPh3)FeGeMe2Cl (2) undergo chloride abstraction by AgBPh4 in the presence of 4-(dimethylamino)pyridine (DMAP) to afford cationic germylene complexes [Cp*(CO)2FeGeMe2·DMAP]BPh4 (3) and [Cp*(CO)(PPh3)FeGeMe2·DMAP]BPh4 (4), respectively. Structural determination by X-ray crystallography of 1 and 3·CH3CN revealed that both complexes have a gauche conformation with respect to the Fe−Ge bonds. The short Fe−Ge bond (2.329(3) Å) and very long Ge−N (DMAP) bond (1.989(8) Å) in 3·CH3CN demonstrate the unsaturated bond character of the former and the dative bond character of the latter. The complexes 3 and 4 in dichloromethane revert to the parent complexes 1 and 2, respectively, via an electron-transfer process from the counteranion, BPh4-, followed by chlorine abstraction from the solvent.