[(eta-C5H4R)Fe(CO)(2)X], X = Cl, Br, I, NO3,CO2Me and [(eta-C5H4R)Fe(CO)(3)](+), R = (CH2)(n)CO2Me (n=0-2), and CO2CH2CH2OH: a new group of CO-releasing molecules

A new group of CO-releasing molecules, CO-RMs, based on cyclopentadienyl iron carbonyls have been identified. X-Ray structures have been determined for [(eta-C5H4CO2Me)Fe(CO)(2)X], X = Cl, Br, I, NO3, CO2Me, [(eta-C5H4CO2Me)Fe(CO)(2)](2), [(eta-C5H4CO2CH2CH2OH)Fe(CO)(2)](2) and [(eta-C5H4CO2Me)Fe(CO)(3)][FeCl4]. Half-lives for CO release, H-1, C-13, and (OC)-O-17 NMR and IR spectra have been determined along with some biological data for these compounds, [(eta-C5H4CO2CH2CH2OH)Fe(CO)(3)](+) and [{eta-C5H4(CH2)(n)CO2Me} Fe(CO)(3)](+), n = 1, 2. More specifically, cytotoxicity assays and inhibition of nitrite formation in stimulated RAW264.7 macrophages are reported for most of the compounds analyzed. [(eta-C5H5)Fe(CO)(2)X], X = Cl, Br, I, were also examined for comparison. Correlations between the half-lives for CO release and spectroscopic parameters are found within each group of compounds, but not between the groups.