HYDROCARBON-BRIDGED COMPLEXES .33. SYNTHESIS OF DINUCLEAR HYDROCARBON-BRIDGED COMPLEXES BY OXIDATION OF FISCHER CARBENE ANIONS AND FERROCENE ENOLATES AND THEIR REACTION

Oxidative coupling of [(OC)(5)Cr=C(OCH3)CH2]Li--(+) and [FcCOCH(2)]K--(+) with AgBF4 gives the dinuclear neutral complexes (OC)(5)Cr=C(OME)CH2CH2C(OMe)=Cr(CO)(5) (1) and FcCOCH(2)CH(2)COFc (2) (Fc = ferrocenyl) in good yield. 1 was characterized by X-ray diffraction. Double deprotonation of 1 and 2 with Bu(II)Li Or KH, respectively, affords dianionic species 3 and 4 which are oxidized to the deeply colored conjugated complexes (OC)(5)Cr=C(OCH3)CH=CHC(OCH3)=Cr(CO)(3) (5) and FcCOCH=CHCOFc (6). Addition of the dianion [(OC)(5)Cr=C(OCH3)CHCHC(OCH3)=Cr(CO)(5)](2-)(Li+)(2) to the cationic electrophiles [Fe(CO)(3)(eta(5)-C6H7)](+)[BF4](-) and [Re(CO)(5)(eta(2)-C2H4)](+)[BF4](-) forms tetranuclear complexes (7, 8) as diastereoisomers. [FcCOCHCHCOFc](2-)(K+)(2) reacts with[Re(CO)(5)(eta(2)-C2H4)](+)[BF4](-) to give the trinuclear complex FcCOCH(2)CH[CH2CH2Re(CO)(5)]COFc (9).