Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
TELSER, Joshua. A perspective on applications of ligand-field analysis: inspiration from electron paramagnetic resonance spectroscopy of coordination complexes of transition metal ions. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.8, pp. 1501-1515. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532006000800005.
This paper describes in a somewhat personal way an overview of the use of electron paramagnetic resonance (EPR) spectroscopy, including high-frequency and -field EPR (HFEPR) to unravel the electronic structure of transition metal ion complexes. The spin Hamiltonian parameters obtained from EPR experiments, namely the g matrix for systems with S =1/2 and the g and D (zero-field splitting) matrices for systems with S > 1/2 provide information on d orbital energy levels. This information can be combined with ligand-field theory (LFT) to provide information on the overall electronic structure of the paramagnetic transition metal complex. As has been discussed by others, LFT is still useful in providing such a quantitative understanding of these complexes, even in the day of advanced computational methods, such as density functional theory (DFT). The discussion is illustrated by examples across the dn configuration.
Keywords : coordination chemistry; EPR; ligand-field theory; spectroscopy.