Picture of a black hole

Strathclyde Open Access research that creates ripples...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of research papers by University of Strathclyde researchers, including by Strathclyde physicists involved in observing gravitational waves and black hole mergers as part of the Laser Interferometer Gravitational-Wave Observatory (LIGO) - but also other internationally significant research from the Department of Physics. Discover why Strathclyde's physics research is making ripples...

Strathprints also exposes world leading research from the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

Assessing the reactivity of sodium zincate [(TMEDA)Na(TMP)ZntBu2] towards benzoylferrocene : deprotonative metalation vs. alkylation reactions

Hevia, Eva and Kennedy, Alan and Mccall, Matthew David (2012) Assessing the reactivity of sodium zincate [(TMEDA)Na(TMP)ZntBu2] towards benzoylferrocene : deprotonative metalation vs. alkylation reactions. Dalton Transactions, 41 (1). pp. 98-103. ISSN 1472-7773

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

Exploring the reactivity of the mixed-metal reagent [(TMEDA)Na(TMP)ZntBu2] (1) towards substituted metallocene benzoylferrocene 2, this study has found that two competing reactivity pathways are available for the sodium TMP-zincate, namely (i) remote 1,6-nucleophilic addition of a tert-butyl group to the phenyl ring of 2, and (ii) simultaneous alpha-deprotonation of the substituted cyclopentadienyl ring of the metallocene and alkylation (1,2-addition) across the CO bond of the carbonyl group. A key organometallic intermediate [(TMEDA)Na(μ-TMP)Zn{OC(tBu)(Ph)(η5-C5H3)Fe(η5-C5H5)}] (3), resulting from the latter reaction has been trapped and characterised by X-ray crystallography and multinuclear (1H and 13C) NMR spectroscopy. Its molecular structure revealed a unique two-fold activation of the tert-butyl groups bonded to zinc in the bimetallic base 1, showing for the first time that each alkyl group can exhibit markedly different reactivities (deprotonation vs. 1,2-addition) towards the same substrate molecule. Iodine interception of the organometallic intermediates of the reaction between 1 and 2 allowed the isolation and characterization (1H, 13C NMR and X-ray crystallography) of the ferrocenyl derivatives [PhC(OH)(tBu)(η5-C5H3I)Fe(η5-C5H5)] (4) and [4-tBu-C6H4C(O)(η5-C5H4)Fe(η5-C5H5)] (5) in a 29% and 24% isolated yield respectively. The low yield observed for the formation of 5 (resulting from the 1,6-addition reaction followed by spontaneous aerobic oxidation during aqueous workup) could be increased to 41% when the reaction mixture was hydrolysed in the presence of the radical oxidant TEMPO.