Synthesis of single and double butterfly iron carbonyl complexes by reactions of [(μ-RSe)(μ-CO)Fe2(CO)6]− anions. Crystal structures of (μ-p-MeC6H4Se)[μ-PhCH2N(H)CS]Fe2(CO)6 and [(μ-PhSe)(μ-MeAs)Fe2(CO)6]2

The in situ reactions of the [Et3NH]+ and [MgBr]+ salts of [(μ-RSe)(μ-CO)Fe2(CO)6]− (1) anions with PhC(Cl)NPh gave single butterfly complexes (μ-RSe)(μ-PhCNPh)Fe2(CO)6 (2, R=Ph; 3, R=p-MeC6H4; 4, R=Et), whereas those of the [Et3NH]+ salts of 1 with R′NCS afforded single butterfly complexes (μ-RSe)[μ-R′N(H)CS]Fe2(CO)6 (5, R=Ph, R′=Ph; 6, R=p-MeC6H4 R′=Ph; 7, R=p-MeC6H4, R′=PhCO; 8, R=p-MeC6H4, R′=PhCH2). Compound 8 could also be prepared by reaction of the [MgBr]+ salt of 1 (R=p-MeC6H4) with PhCH2NCS followed by treatment with CF3CO2H. More interestingly, while the [Et3NH]+ salt of 1 (R=Ph) reacted with Et3OBF4 to give a carbyne ligand-bridged single butterfly complex (μ-PhSe)(μ-EtOC)Fe2(CO)6 (9), reaction of the [Et3NH]+ salt of 1 (R=Ph) with MeAsI2 produced a MeAsAsMe ligand-bridged double butterfly complex [(μ-PhSe)(μ-MeAs)Fe2(CO)6]2 (10). All the new complexes, 2–10, were characterized by elemental analysis and various spectroscopic methods, for complexes 8 and 10, the structures were also confirmed by X-ray diffraction techniques.