Picture of UK Houses of Parliament

Leading national thinking on politics, government & public policy through Open Access research

Strathprints makes available scholarly Open Access content by researchers in the School of Government & Public Policy, based within the Faculty of Humanities & Social Sciences.

Research here is 1st in Scotland for research intensity and spans a wide range of domains. The Department of Politics demonstrates expertise in understanding parties, elections and public opinion, with additional emphases on political economy, institutions and international relations. This international angle is reflected in the European Policies Research Centre (EPRC) which conducts comparative research on public policy. Meanwhile, the Centre for Energy Policy provides independent expertise on energy, working across multidisciplinary groups to shape policy for a low carbon economy.

Explore the Open Access research of the School of Government & Public Policy. Or explore all of Strathclyde's Open Access research...

What can NMR spectroscopy of selenoureas and phosphinidenes teach us about the π-accepting abilities of N-heterocyclic carbenes?

Vummaleti, Sai V. C. and Nelson, David J. and Poater, Albert and Gomez-Suarez, Adrian and Cordes, David B. and Slawin, Alexandra M. Z. and Nolan, Steven P. and Cavallo, Luigi (2015) What can NMR spectroscopy of selenoureas and phosphinidenes teach us about the π-accepting abilities of N-heterocyclic carbenes? Chemical Science. ISSN 2041-6520

PDF (Vummaleti-etal-CS-2015-What-can-NMR-spectroscopy-of-selenoureas-and-phosphinidenes-teach-us)
Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (1MB)| Preview


    The electronic nature of the interaction of NHCs with metal centres is of interest when exploring their properties, how these properties influence those of metal complexes, and how these properties might depend on ligand structure. Selenourea and phosphinidene complexes have been proposed to allow the measurement of the [small pi]-accepting ability of NHCs, independent of their [sigma]-donating ability, via the collection of 77Se or 31P NMR spectra, respectively. Herein, the synthesis and characterisation of selenoureas derived from a range of imidazol-2-ylidenes, 4,5-dihydroimidazol-2-ylidenes and triazol-2-ylidenes are documented. Computational studies are used to explore the link between the shielding of the selenium centre and the electronic properties of the NHCs. Results show that [small delta]Se is correlated to the energy gap between a filled lone pair orbital on Se and the empty [small pi]* orbital corresponding to the Se-NHC bond. Bond energy decomposition analysis indicated no correlation between the orbital [sigma]-contribution to bonding and the chemical shielding, while a good correlation was found between the [small pi]-contribution to bonding and the chemical shielding, confirming that this technique is indeed able to quantify the ability of NHCs to accept [small pi]-electron density. Calculations conducted on phosphinidene adducts yielded similar results. With the link between [small delta]Se and [small delta]P and [small pi]-back bonding ability clearly established, these compounds represent useful ways in which to fully understand and quantify this aspect of the electronic properties of NHCs.