STUDIES ON REACTIVITIES OF ISOMERIZED YCLOHEXADIENE(DICARBONYL)[ETHOXY(ARYL)CARBENE]IRON COMPLEXES - CRYSTAL-STRUCTURES OF [C6H8(CO)(3)FEC(OC2H5)C6H5], [C6H8(CO)(2)(P(OME)(3))FEC(OC2H5)C6H4CF3-P], AND [C6H8(CO)(3)FEC(OC2H5)C6H4CH3-P]

The reactions of the isomerized yclohexadiene(dicarbonyl)[ethoxy(aryl) carbene]iron complexes [2-4-eta-C6H8(CO)(2)FeC(OC2H5)Ar] (1, Ar = C6H5 ; 2, Ar = m-CH3C6H4; 3, Ar = p-CH3C6H4; 4, Ar = p-CF3C6H4) with [(NH4) (2)Ce(NO3)(6)] in EtOH solution at low temperature give eta(3)-cyclohe xadienyltricarbonyliron complexes [2-4-eta-C6H8(CO)(3)FeC(OC2H5)Ar] (5 , Ar = C6H5; 6, Ar = m-CH3C6H4; 7, Ar = p-CH3C6H4; 8,Ar = p-CF3C6H4) C ompelxes 1-4 reacted with CO gas under similar conditions to afford th e same products 5-8 in high yields. The reaction between compound 4 an d Lewis bases P(n-Bu)(3), P(OMe)(3), P(OPh)(3), PPh3, and AsPh3 gave t he chelated allyliron adducts [2-4-eta-C6H8(CO)(2)(L)FeC(OC2H5)C6H4CF3 -p] (9, L = P(n-Bu)(3); 10, L = P(OMe)(3); 11, L = P(OPh)(3); 12, L = PPh3; 13, L = AsPh3). The thermal decomposition of complexes 3 and 7 y ielded the eta(3)-cyclohexadienyltricarbonyliron complex [3-5-eta-C6H8 (CO)(3)FeC(OC2H5)C6H4CH3-p] (14) The structures of complexes 5, 10, an d 14 have been established by X-ray diffraction studies.