FERROCENYL LIGANDS .3. BULKY FERROCENYL DERIVATIVES - 1,1'-BIS(DIPHENYLPHOSPHINO)-3,3'-BIS(TRIMETHYLSILYL)FERROCENE - SYNTHESIS, METAL COMPLEXATION AND THE CRYSTAL AND MOLECULAR-STRUCTURE

The attempted syntheses of ferrocenyl phosphines with bulky substituents are reported using N,N,N',N'-tetramethylethylenediamine (TMED)/BuLi metallation reactions. 1,1'-3,3'-Tetrakis(trimethylsilyl)ferrocene was prepared by this route and also the title compound I. Attempts to prepare 1,1'-bis(triorganotin)3,3'-bis(trimethylsilyl)-ferrocenes failed. Only one of the two diastereomeric forms of I was obtained, indicating a regiospecific metallation of the precursor 1,1'-bis(trimethylsilyl)ferrocene. A single crystal X-ray study of this isomer is presented and its structure showed a cisoid disposition of the PPh2 groups. This results in a through-space interaction of the two phosphorus atoms as revealed by long range phosphorus-carbon coupling in the C-13 NMR spectrum of I. A preliminary study of some metal complexes of I is also included together with P-31 NMR and Fe-57 Mossbauer spectroscopic data.