Reactions of a gallium-bridged duron complex with alkyl lithium, HCl, and phosphines

Article abstract of DOI:10.1021/om800310h

Gallium-bridged diiron complex Cp*(dppe)FeGaFe(CO)₄ (2, Cp* = η-C₅Me₅, dppe = Ph₂CH ₂CH₂PPh₂) did not react with [PPN]Cl, DMAP (4-N,N-dimethylaminopyridine), and bpy (2,2′-bipyridine); however, reaction of 2 with HCl caused Ga-Fe(CO)₄ bond fission to give Cp*(dppe)FeGaCl₂ (4). The Ga-Fe(CO)₄ bond cleavage also occurred by the reaction of 2 with RLi (R = Me, ⁿBu) to afford Cp*(dppe)FeGaR₂ (R = Me (5a), ⁿBu (5b)). Irradiation of 2 in the presence of phosphine PR₃ (R = OPh, Me, and OMe) gave Cp*(dppe)FeGaFe(CO)₃L (L = P(OPh)₃ (6a), PMe ₃ (6b), and P(OMe)₃ (6c)) and Cp*(dppe)-FeGaFe(CO) ₂L₂ (L = PMe₃ (7b) and P(OMe)₃ (7c)) depending on the reaction conditions. Cleavage of the Cp*(dppe)Fe - Ga bond occurred by irradiation of 2 in the absence of PR₃ to give hydridoiron complex Cp*(dppe)FeH (8) via abstraction of hydrogen from solvent. Structural investigation of 6a and 6b revealed that substitution of CO with an electron-releasing ligand PR₃ caused shortening of the Ga - Fe(CO)₃L bond and elongation of the Cp*(dppe)Fe-Ga bond.