Insertion reactions of CS2, COS, and PhNCS at thiolate-bridged diiron centers

Treatment of [Cp*Fe(μ2-SR)3FeCp*] (1a, R = Et; 1b, R = Me) with CS2 obtains the insertion products [Cp*Fe(μ2-SR)2(μ-η2-S2CSR)FeCp*] (2a, R = Et; 2b, R = Me) with the retained Fe2S2 subunit in excellent yield. 2a and 2b represent the first examples for the CS2 activation and incorporation at the diiron–SR bond. [Cp*Fe(μ2-SEt)2(μ-η2-S2)FeCp*] (3) is prepared from COS and 1a through the decarbonylation and sulfur coupling reaction of COS resulting in the formation of S22− ligand. Addition of PhNCS into 1a affords a mononuclear complex [Cp*Fe(SEt)(η2-SC(SEt)NPh)] (4). 1a is found to be unreactive towards CO2. The spectral characterization, X-ray diffraction analysis, and electrochemistry of the insertion products have also been described.