Syntheses, spectra and crystal structure of (CO)2(NO)Cr(η5-C5H4)CH2(η5-C5H4)Fe[vinyl-(η5-C5H4)]

FriedelCrafts acetylation of [η5-(ferrocenylmethyl)cyclopentadienyl]dicarbonylnitrosylchromium (hereafter called cynichrodenylferrocenylmethane) (3) has afforded (1′-acetylferrocenyl)-cynichrodenylmethane (5) in 63% yield. Reduction of 5 with sodium borohydride gives 1-[1′-(cynichrodenylmethyl)ferrocenyl]ethanol (6). Dehydration of 6 produces [η5-(1′-vinylferrocenyl)methyl]cyclopentadienyl]dicarbonylnitrosylchromium (7), a promising organometallic monomer, in 80% yield. The structure of 7 has been solved by an X-ray diffraction study: space group Pbca, a 10.966(2), b 12.595(1), c 26137(3) A, and Z = 8. The vinyl group and the exocyclic carbon are in the 1,3′-configuration with an average rotation of 7° of the corresponding Cp(Fe) rings from the eclipsed configuration.