Synthesis of thiolate and phosphido bridged iron-manganese complexes; molecular structure of cis-[FeMn(mu-CO)(mu-SEt)(CO)(2)(Cp)(C5H4Me)]

The reaction of [Fe(CO)(2)(SR)(Cp)] (R = Et, Ph; Cp = eta-C5H5) with [Mn(CO )(2)(thf)(C5H4Me)] (thf = tetrahydrofuran), under photolytic conditions, le ads to the formation of the novel heterodinuclear bridged thiolate complexe s [FeMn(mu-CO)(mu-SR)(CO)(2)(Cp)(C5H4Me)] in low yields. [FeMn(mu-CO)(mu-SE t)(CO)(2)(Cp)(C5H4Me)] consists of a mixture of cis and trans isomers which have been separated and characterized by LR and NMR spectroscopy. The IJ-p hosphido complex [FeMn(mu-CO)(mu-PPh2)(CO)(2)(Cp)(C5H4Me)] has been prepare d analogously from [Fe(CO)(2)(PPh2)(Cp)] and [Mn(CO)(2)(thf)(C5H4Me)]. Vari able temperature NMR spectra of the latter heterodinuclear complex, in CDCl 3 show the presence of an equilibrium mixture of the two interconverting ci s and -trans isomers. The X-ray molecular structure of cis-[FeMn(mu-CO)(mu- SEt)(CO)(2)(Cp)(C5H4Me)] shows a bonded Fe-Mn interaction [2.617(2) Angstro m] reinforced by a mu-CO and a mu-SEt ligands. The molecule contains chiral centers at the iron, manganese and sulfur atoms and the diastereoisomer un der study exhibits optimized non bonded contacts between the alkyl groups. (C) 1999 Elsevier Science S.A. All rights reserved.