Oxo-rhenium(V) complexes with analogs of bis(diphenylphosphino)ethane

Abstract

Compounds of the types ReOCl 3(L–L) and ReOCl 2(OEt)(L–L) with bis(diphenylphosphino)ethene (dppen) and bis(diphenylphosphino)ferrocene (dppf) were prepared by reacting the diphosphine with ReOCl 3(OPPh 3)(Me 2S). The ReOCl 3(L–L) compound with bis(diphenylarsino)ethane (dpae) was prepared similarly. Crystallographic work on ReOCl 3(dppen) and ReOCl 3(dpae) confirmed the approximate octahedral environment of the metal and the presence of a Cl ligand trans to the Re O bond. The ReOCl 2(OEt)(L–L) compounds contain a transO Re-OEt unit. The visible spectra of both types of compounds include a two-component d–d absorption pattern originating from the spin-allowed excitation of a d electron from the interaxial d orbital in the equatorial plane to the empty d xz and d yz orbitals. For ReOCl 2(OEt)(dppf), these bands are masked by strong transitions taking place in the ferrocene moiety. The absorptions of the other systems are not greatly displaced compared to the similar dppe compounds, a small decrease in the transition energy being noted for the dpae complex.