Synthesis and Characterization of Iron Nitrosyl Thiolate Complexes; Studies of Nitrite Reduction by Iron Thiolate Complexes

Abstract

Nitric oxide (NO) is not only an important small molecule in physiology and pathology but also an essential intermediate during the denitrifying process in bacteria In order to understand iron nitrosyl intermediates in biological systems several iron nitrosyl complexes are obtained and studied at this work They are [PPh4][Fe(PS3”)(NO)] (1) [Fe(PS3”)(NO)] (2) and [Fe(PSS-S”)2(NO)] (3) (PS3”: tris(benzenethiolato)phosphine) Complexes 1 and 3 are {FeNO}7 species Complex 2 is a {FeNO}6 species Complexes 1 and 2 both have five-coordinated iron centers with distorted trigonal bipyramidal geometry but complex 3 embraces a five-coordinated iron center and the geometry of complex 3 is more likely trigonal bipyramid geometry All three complexes have been characterized by UV-vis-NIR and NMR spectroscopies The electrochemical properties have been studied by cyclic voltammogram and magnetic nature is investigated by SQUID and EPR measurements In addition reactions of [PPh4][Fe(PS3”)(CH3CN)] (4) and [PPh4][Fe(PS3”)(OCH3)] (5) reported previously in our laboratory with nitrite are also investigated The ESI-MS and UV-vis-NIR spectroscopies are used to follow the reaction profiles Adding 4~5 equivalents of nitrite to [PPh4][Fe(PS3”)(CH3CN)] (4) results in the formation of [PPh4][Fe(PS3”)(NO)] (1) The reaction intermediates are observed in ESI-MS spectra The reaction pathways are elucidated accordingly

Date of Award	2017 Jan 23
Original language	English
Supervisor	Hua-Fen Hsu (Supervisor)