Reactivity of distorted C5H5Fe(CO)2 (olefin) cations toward nucleophilic attack

A study of β-hydride abstraction from alkanediyl homobimetallic complexes [{Cp(CO)2Fe}2{μ-(CnH2n)}] (n=4–10, Cp=η5-C5H5)

“…The influence of an asymmetric centre is often observed in protons that are more than two bonds away from the asymmetric centre. The pattern of signals in the spectra, especially the signals assignable to the a-CH 2 protons, resemble those observed in the reported complexes [{Cp(CO) 2 Fe(CH 2 @CHOEt)]PF 6 [16] and [{Cp(CO) 2 Fe(CH 2 @CHOMe)]PF 6 [17] in which the metals have been shown to be g 2 -bonded to the carbenium ion moieties. Evidently, therefore, the same bonding prevails in these bimetallic complexes.…”

A NMR, X-ray, and DFT combined study on the regio-chemistry of nucleophilic addition to platinum(II) coordinated terminal olefins

“…The explanation was found in an 0022-328X/$ -see front matter Ó 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.jorganchem.2008.05.040 increased contribution of the limiting structure [CpFe(CO) 2 (CH 2 -CH@NMe 2 )] + which reduces the bond order between the two carbon atoms [5]. Recent structural and computational studies performed on this iron complex have come to the same conclusion [6].…”

“…Therefore the energy of the LUMO appears to be a much better indicator of the olefin reactivity than other parameters such as the overall charge of the complex. On this basis Hoffmann and Eisenstein could rationalize the striking different behaviour of two isolobal complexes: [CpFe(CO) 2 (C 2 H 4 )] + [4], which is very reactive towards nucleophiles, and [Fe(CO) 5 (C 2 H 4 )] 2+ [3], which is un-reactive.…”

“…The work of Rosenblum on [CpFe(CO) 2 (CH 2 @CHOMe)] + , where the coordinated olefin bears an electron donor substituent, did show the complete regio-specificity of the nucleophilic addition and the unique formation of the Markovnikov product [5]. The X-ray structure of [CpFe(CO) 2 (CH 2 @CHOMe)] + did show a longer Fe-C olefin bond distance for the substituted carbon, indicative of a certain degree of olefin ''slippage" already in the ground state of the complex molecule.…”

Enhancing Electrophilic Alkene Activation by Increasing the Positive Net Charge in Transition‐Metal Complexes and Application in Homogeneous Catalysis

“…[5] Notably, a similar reaction was reported by Rosenblum et al in which the allylic ligand of [Fe(Cp)-(CO) 4 (CH 2 CH=CH 2 )] added as a nucleophile to the coordinated ethylene in [Fe(Cp)(CO) 4 (CH 2 =CH 2 )]. [50] However, other examples of a reaction between an alkene complex and a free alkene giving an isolable complex, to the authors knowledge, are not described to date. Interestingly, complexes of higher substituted alkenes than ethylene, for example, propene or 1-butene did not react with the internal alkenes; these prevent side reactions such as oligomerization.…”