PUB - Publikationen an der Universität Bielefeld

The ([eta]-3-phosphaallyl)iron complex ([eta]5-C5Me5)(CO)Fe{[eta]3-P[CH(SiMe3)2](CHC = O)}(1) is oxidized by sulfur and selenium to afford the methylenethioxo- and methyleneselenoxo-phosphorane complexes 4 and 5 with an anti-configuration of the CH(SiMe3)2 substituent relative to iron. The chalcogene atoms are attached to the phosphorus atom of the ligand and do not participate in the bonding to the metal. Equivalent amounts of 1 and Fe2(CO)9 lead to the phosphaalkenyl complex 6 with an Fe - C [sigma] bond. On the other hand, a large excess of Fe2(CO)9 converts 1 as well as 6 into the cluster compound 7 featuring the bridging 1-oxa-4-phosphabutadiene ligand ([eta]5-C5Me5)(CO)2Fe-C(O)-CH = P-CH(SiMe3)2. Constitution and configuration of all compounds have been elucidated by spectroscopic methods (IR, H-1, C-13, P-31 NMR, and MS). In addition complexes 5 and 7 have been characterized by single crystal X-ray diffraction analyses.