DIALKYLAMINOPHOSPHORUS METAL-CARBONYLS .13. STRUCTURE OF A TERTIARY ALCOHOL [((PR2NP)-PR-I)(2)C(OH)R]FE-2(CO)(6) AND THE EFFECT OF CARBON HYBRIDIZATION ON THE GEOMETRY OF THE CP2FE2 CAGE

Reaction of ((Pr2NP)-Pr-i)(2)COFe2(CO)(6) with benzyllithium (from PhC H(2)SnPh(3)+n-BuLi) gives the corresponding tertiary alcohol ((Pr2NP)- Pr-1)(2)C(CH(2)Ph)(OH)Fe-2(CO)(6), which has been characterized struct urally by X-ray diffraction (monoclinic; space group, P2(1)/a; a=9.797 (1), b=16.593(1) and c=19.671(2) Angstrom; beta=101.564(9)degrees; Z=4 ). A comparison of the geometries of the CP2Fe2 cages in the series (( Pr2NP)-Pr-i)(2)C(CH(2)Ph)(OH)Fe-2(CO)(6) and [((Pr2NP)-Pr-i)(2)CHSiMe( 3)]Fe-2(CO)(6) with P-C(sp(3))-P bridges and ((Pr2NP)-Pr-i)(2)COFe2(CO )(6), ((Pr2NP)-Pr-i)((t)Bu(2)PP)COFe2(CO)(6), and ((t)BuP)(2)COFe2(CO) (6) with P-C(sp(2))-P bridges indicates that changing the P bridging ( i.e. cage) carbon atom from sp(3) hybridization to sp(2) hybridization increases the P-C-P bond angle from 78-80 to 84-86 degrees, the P-Fe- P bond angles from 64-67 to 69-70 degrees, and the non-bonding P ... P distance from 2.44 to 2.53-2.55 Angstrom while having relatively litt le effect on the P-C, Fe-P and Fe-Fe distances.