Rearrangement of the Tris(2-pyridylthio)methanido Ligand in an Iron(II) Complex Containing an Fe−C Bond

Iron(II) tris(2-pyridylthio)methanido (1) containing an Fe−C bond, obtained from the reaction of tris(2-pyridylthio)methane (HL1) and iron(II) triflate, reacts with protic acid to generate iron(II) bis(2-pyridylthio)carbene (1a). The carbene complex is converted to an iron(II) complex (2) of the 1-[bis(2-pyridylthio)methyl]pyridine-2-thione ligand (L3) upon treatment with a base. Complex 2 reversibly transforms to 1a in the presence of an acid. During the transformation of 1 to 2, a novel rearrangement of L1 to L3 takes place. The iron(II) complexes are reactive toward dioxygen to form the corresponding iron(III) complexes.