Influence of different solvents on structures and electronic properties of new Fe2S2 complexes containing bis(2-diphenylphosphinophenyl)ether

In order to observe solvent effects on structures and properties of [FeFe]-hydrogenase, two Fe 2 S 2 complexes, [Fe 2 (μ-pdt)(CO) 4 (DPEphos)] • CH 2 Cl 2 ( 1 ) and [Fe 2 (μ-pdt)(CO) 4 (DPEphos)] •[Fe 2 (μ-pdt)(CO) 4 (DPEphos)] ( 2 ) (DPEphos =bis(2-diphenyl phosphinophenyl)ether), have been prepared and characterized by IR, 1 H NMR, 31 P NMR, TG and X-ray crystal structure analysis. Structural analysis shows that the [Fe 2 (μ-pdt)(CO) 4( DPEphos)] unit in 1 and 2 includes a butterfly Fe 2 S 2 core, in which each iron atom is five-coordinated with a pseudo-square pyramidal geometry, and the change of the crystallization solvent from CH 2 Cl 2 to toluene leads to the variation of crystallographic system, space group and the weak interactions. DFT studies indicate that the component of the HOMOs and LUMOs at different solvents for [Fe 2 (μ-pdt)(CO) 4( DPEphos)] are nearly identical, which are primarily composed of CO, μ-pdt, Fe atoms and -Ph 2 P groups, coinciding with the change of DOS and PDOS at different solvents. Meanwhile, the HOMO and LUMO energies, HOMO → LUMO energy gap and Mülliken atomic charges at methanol, ethanol, dichloromethane and nitrobenzene are only a little change, which have much more changes than the relevant values at solvent-free model. All these show that the solvent has an important influence on structures and electronic properties of Fe 2 S 2 complexes.