Investigation of Syntheses and Spectra (UV,IR,CV) of Some Fe3S3 Cluster Compounds

Two new Fe 3S 3 cluster compounds, compound 5 〔Et 4N〕 3〔Fe 3( p ClPhS) 3Cl 6〕 and compound 6 〔Et 4N〕 3〔Fe 3(Cl 5PhS) 3Cl 6〕 have been successfully synthesized with one step reaction. Combination of compounds 5,6 and compounds 1~4 which were synthesized earlier, their UV,IR and CV spectra have been studied systematically, deeply to understand molecular electronic characteristics. There is a blueshift within 260nm and a redshift over 260nm in the UV spectra of compounds, it has been shown that Fe-S cluster needs more energy in transition of electric charge (CT), but needs less energy in d d transition area. In the IR spectra, the most interesting bands appearing in the regions of 422~386cm -1 and 492~474cm -1 are attributed to S-Fe-S (Fe 3S 3 unit) and FeS (Ph-S) stretching vibration respectively. The bands in the region 330~285cm -1 and 245~183cm -1 can be assigned to Fe-Cl and Fe-Br stretching vibration respectively. Their CV spectra show that this is a quasi reversible redox process. In this process, an Fe 2+ loses an electron and is oxidized to Fe 3+ , then gets an electron and is reduced to Fe 2+ . The redox electrical potentials of compounds 1, 3~6 are +0.07V / -0.60V, +0.24V / -0.80V, +0.40V / -0.80V, +0.43V / -1 20V, +0.54V/-1.00V, respectively.