1,2-DIPHOSPHAFERROCENES AS LIGANDS IN TRA NSITION-METAL COMPLEXES. X-RAY STRUCTURE-ANALYSIS OF -[CO-2(CO)(6)]-3,4-(ME(3)SIO)(2)-5-(ME(3)SI)P2C3)]

Reaction of metallo-1,2-diphosphapropene (eta(5)-tBuC(5)H(4))(CO)(2)Fe -P(SiMe(3))-P = C(SiMe(3))(2) with (Z-cyclooctene)Cr(CO)(5) afforded t he pentacarbonylchromium adduct of a 1,2-diphosphaferrocene -[Cr(CO)(5 )]-3,4-(Me(3)Sio)(2)-5-(Me(3)si)P2C3)Fe] (1c). Diphosphaferrocene [(et a(5)- H(4)){eta(5)-3,4-(Me(3)SiO)(2)-5-(Me(3)Si)P2C3}Fe] (2c) was form ed when (eta(5)-tBUC(5)H(4)) (CO)aFeBr was treated with (Me(3)Si)2P-P = C(SiMe(3))(2) in toluene at 60 degrees C. Photolysis of molybdenum- and tungsten hexacarbonyl in the presence of H(3)){eta(5)-3,4-(Me(3)Si O)(2)-5-(Me(3)Si)P2C3}Fe] (2b) gave the pentacarbonylmetal adducts 8 ( M = Mo) and 9 (M = W), respectively. A corresponding manganese derivat ive resulted from the photochemical reaction of 2b and (MeC(5)H(4))Mn( Co)(3). Treatment of 2b with Co-2(CO)(8) yielded trinuclear Co-2(CO)(6 )]-3,4-(Me(3)SiO)(2)-5-(Me(3)Si)P2C3}Fe] (11). Constitution and config uration of compounds 1c, 2c, 8-11 were determined by elemental analyse s and spectra (IR, H-1-, C-13-, P-31-NMR, MS). In addition the molecul ar structure of 11 was established by single crystal X-ray analysis.