Novel μ-CO-containing butterfly Fe/S cluster anions generated from tetrathiols, Fe3(CO)12, and Et3N:: Their reactions with electrophiles to give neutral butterfly Fe/S cluster complexes

Tetrathiol 1,2,4,5-(HSCH2)(4)C6H2 reacted with Fe(CO)(12) and Et3N followed by treatment of the intermediate mu-CO-containing tetraanion {[(mu-CO)Fe-2(CO)(6)](4)[1,2,4,5-(mu-SCH2)(4)C6H2]}(4-) (7) with 2-furan-carbonyl chloride to give quadruple-butterfly complex [(mu-sigma,pi-C4H3O)Fe-2(CO)(6)](4)[1,2,4,5-(mu-SCH2)(4)C6H2] (9), whereas triple-butterfly complex [(mu-Ph2P)Fe-2(CO)(6)](2)[Fe-2(CO)(6)][1,2,4,5-(mu-SCH2)(4)C6H2] (11) could be produced by reaction of Ph2PCl with the mu-CO-containing dianion {[(mu-CO)Fe-2(CO)(6)](2)[Fe-2(CO)(6)][1,2,4,5(mu-SCH2)(4)C6H2]}(2-) (10) generated in situ from the initially formed tetraanion 7. Similarly, the triple-butterfly complexes [(mu-Ph2P)Fe-2(CO)(6)](2)[Fe-2(CO)(6)][(mu-SCH2)(4)C] (14) and [(mu-sigma,pi-CH2CH=CH2)Fe-2(CO)(6)](2)-[Fe-2(CO)(6)][(mu-SCH2)(4)C] (16) were produced by reaction of Ph2PCl or CH2=CHCH2Br with the mu-CO-containing dianion {[(mu-CO)Fe-2(CO)(6)](2)[Fe-2(CO)(6)] [(mu-SCH2)(4)C]}(2-) (13) formed in situ from tetraanion {[(mu-CO)Fe-2(CO)(6)](4)[(mu-SCH2)(4)C]}(4-) (12) generated initially by reaction of tetrathiol C(CH2SH)(4) with Fe-3(CO)(12) and Et3N. The double-butterfly complex [Fe-2(CO)(6)](2)[(mu-SCH2)(4)C] (15) derived in situ from dianion 13 was also isolated as a minor product along with major products 14 and 15. All the new complexes 9, 11, and 14-16 were characterized by elemental analysis and IR and NMR spectroscopy, as well as by X-ray crystallography for 9, 11, 14, and 15.