Isoprenetricarbonyliron reacts with aryllithium, RLi (R = C6H5, p-CH3C6H4, p-CH3OC6H4, p-CF3C6H4), in ether at low temperature to yield acylmetallate complexes, from which, by subsequent alkylation with Et3OBF4 in aqueous solution at O? the orange-red crystalline complexes with the composition C5H8(CO)2FeC(OC2H5)R (I) formulated as isomerized products of isoprene(dicarbonyl)(ethoxyarylcarbene)iron complexes were obtained. When LiC6Cl5 was used as a nucleophile, the alkylation of acylmetallate intermediate formed under the same conditions gave known complex (CO)4FeC(OC2H5)C6Cl5 (II). The mol. structures of I (R = Ph) and II have been deduced from their single crystal x-ray diffraction data.

Key words: CRYSTAL STRUCTURE DETERMINATION, INFRARED SPECTROPHOTOMETRY, X-RAY DIFFRACTION ANALYSIS, IRON COMPLEX, CARBONYL COMPLEX, CARBENE, PROTON MAGNETIC RESONANCE SPECTROMETRY, LITHIUM COMPOUNDS, SINGLE CRYSTALS, TRANSITION METAL COMPLEX