Synthesis, characterization and electrochemistry of dinuclear iron complexes with SNC donors

The three-component reactions of PhNHC(S)OR, Et3N and Fe-3(CO)(12) in THF at 0 degrees C afford the [Et3NH](+) salt of the [(mu-PhNCOR)Fe-2(CO)(6)(mu-S)](-) cluster anion (R = CH3, CH2Ph). The S-centered cluster anion reacts with CH3I to give (mu-k(2)N,C-PhNCOR)Fe-2(CO)(6)(mu-SCH3) (1, R = CH3; 3, R = CH2Ph) and (mu-k(2)N,C-PhNCOCH3)Fe-2(CO)(6)(mu(4)-S)Fe-2(CO)(6)(mu-SCH3) (2). Further reactions of 1 with 1 equiv of PPh2R in the presence of Me3NO lead to the corresponding monophosphine-substituted complexes (mu-k(2)N,C-PhNCOCH3)Fe-2(CO)(5)(L)(mu-SCH3) (4, L = PPh3; 5, L = PPh2Py). Similarly, reactions of 3 with PPh2R produce the corresponding monophosphine-substituted complexes (mu-k(2)N,C-PhNCOCH2Ph)Fe-2(CO)(5)(L)(mu-SCH3) (6, L = PPh3; 8, L = PPh2Py) besides an unexpected monophosphine-disubstituted complex (mu-k(2)N,C-PhNCOCH2Ph)Fe-2(CO)(4)(PPh3)(2)(mu-SCH3) (7). All the new complexes have been characterized by elemental analyses, IR, H-1 NMR, C-13 NMR and P-31 NMR spectroscopy and 1, 2 and 4-8 structurally determined by X-ray crystallography. Electrochemical studies indicate that when using HOAc or TFA as a proton source, complexes 1, 4-6 and 8 exhibit catalytic H-2 production. (C) 2018 Elsevier Ltd. All rights reserved.