Synthesis, Structure, and Reactivity of the [Fe₄S₄(SR)₄]^2-(R = 2-, 3-, and 4-Pyridinemethane) Clusters

Abstract

The [Fe 4 S 4 ]2+ clusters with 2-, 3-, and 4-pyridinemethanethiolate (S2-Pic, S3-Pic, and S4-Pic, respectively) terminal ligands have been synthesized from the ligand substitution reaction of the ( + transition decreased in the order of II, III and IV, and the reduction potential changes by the ligands were explained based on the structural differences among the complexes. The complex III was reacted with sulfonium salt of [PhMeSCH 2 -p-C 6 H 4 CN](BF 4 ) in MeCN to test possible radical-involving reaction as a functional model of the [Fe 4 S 4 ]-SAM (S-adenosylmethionine) cofactor. However, the isolated reaction products of 3-pyridinemethanethiolate-p-cyanobenzylsulfide and thioanisole suggested that the reaction followed an ionic mechanism and the products formed from the terminal ligand attack to the sulfonium.