ORGANOMETALLOIDAL DERIVATIVES OF THE TRANSITION-METALS .25. NATURE OF THE FE-SI BONDS IN OLIGOSILANE COMPLEXES OF THE INDENYLIRON DICARBONYL SYSTEM - (ETA-5-C9H7)FE(CO)(L)SIN (SIN=SIME3, SI2ME5, 2-SI3ME7 - L=CO, PPH3)

Complexes of the general type (η5-C9H7)Fe(CO)(L)Sin (η5-C9H7 = η5-indenyl; Sin = SiMe3, Si2Me5,2-Si3Me7; L = CO, PPh3) have been synthesized and characterized via X-ray crystallography. Substitution of the CO ligand by PPh3 results in a significant increase in both the Fe-Si and Si-Si bond distances. The results rule out a significant contribution of any -bonding to the Fe-Si bond in both the dicarbonyl and carbonyl phosphine systems and imply that steric considerations dominate the various structural changes. The η5-indenyl groups exhibit their characteristic “slipfold” distortion, which becomes larger as the steric bulk of the other ligands increases. The synthesis of (η5-C9H7)Fe(CO)(L)SiMe(SiMe3)2 was accomplished via photochemical rearrangement of (η5-C9H7)Fe(CO)2SiMe2SiMe2SiMe3 in the presence or absence of PPh3.29Si NMR data are in accord with the structures and previous NMR studies on silyliron complexes. © 1990, American Chemical Society. All rights reserved.