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 [(mu -RSe)(mu -CO)Fe-2(CO)(6)](-) (1) anions with PhC(CI)=NPh gave single butterfly complexes (mu -RSe)(mu -PhC=NPh)Fe-2(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 (mu -RSe)[mu -R 'N(H)C=S]Fe-2(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 (mu -PhSe)(mu -EtOC)Fe-2(CO)(6) (9), reaction of the [Et3NH](+) salt of 1 (R = Ph) with MeAsI2 produced a MeAs-AsMe ligand-bridged double butterfly complex [(mu -PhSe)(mu -MeAs)Fe-2(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. (C) 2001 Elsevier Science B.V. All rights reserved.