Electronic structure of the glyoxalbis(2-hydroxyanil) (gha) ligand in [CoIII(gha)(PPh3)2]+: radical vs. non-radical states
Roy, A., Muresan, N., Tuononen, H., Rath, S., & Ghosh, P. (2008). Electronic structure of the glyoxalbis(2-hydroxyanil) (gha) ligand in [CoIII(gha)(PPh3)2]+: radical vs. non-radical states. Dalton Transactions, (26), 3438-3446. doi:10.1039/B802063A
Published inDalton Transactions
DisciplineEpäorgaaninen ja analyyttinen kemia
© The Royal Society of Chemistry 2008. This is a final draft version of an article whose final and definitive form has been published by RSC. Published in this repository with the kind permission of the publisher.
The synthesis, structure and spectroscopic properties of a complex salt [CoIII(gha)(PPh3)2][CoIICl3(PPh3)]·C2H5OH (1) are reported; gha = glyoxalbis(2-hydroxyanil). This is the first single crystal X-ray structure of a (gha)2− complex with a transition element. Though the determined bond parameters and UV-Vis spectroscopic data correlate well with a diradical description for the cation in 1, detailed electronic structure calculations using density functional theory confirm that [Co(gha)(PPh3)2]+ can be described as a closed shell singlet species which nevertheless displays an interesting electronic structure with significant electron transfer to the formally unoccupied LUMO of the square planar [Co(gha)]+ fragment. It was found that without the phosphine coligands, the [Co(gha)]+ unit has a triplet ground state with the lowest energy singlet diradical state lying only 1 kcal mol−1 higher in energy. The chemistry of the gha ligand is of interest as a spin diverse redox active system.