The neutral title compds. with Q = 3,5-di-tert-butyl-o-quinone or 4,6-di-tert-butyl-N-phenyl-o-iminobenzoquinone (Qx) were studied by UV-visible-NIR spectroelectrochem. and by EPR spectroscopy in the case of the odd-electron monocation and monoanion intermediates. Supported by DFT and TD-DFT calcns., the results indicate stepwise electron removal from predominantly ligand-based delocalized MOs on oxidn. whereas the stepwise electron uptake on redn. involves unoccupied MOs with considerably metal-ligand mixed character. In both cases, the strong near-IR absorption of the neutral precursors diminishes. In comparison to the ruthenium series, the osmium analogs exhibit larger transition energies from enhanced MO splitting and a different EPR response due to the higher spin-orbit coupling. The main difference between the quinone (1n, 2n) and corresponding monoiminoquinone systems (3n, 4n) is the shift of $\sim$0.6 V to lower potentials for the monoimino analogs. While the absorption features do not differ markedly, the EPR data reflect a higher degree of covalent bonding for the complexes with monoimino ligands. on SciFinder(R)
%0 Journal Article
%1 Das.2012f
%A Das, Atanu Kumar
%A Huebner, Ralph
%A Sarkar, Biprajit
%A Fiedler, Jan
%A Zalis, Stanislav
%A Lahiri, Goutam Kumar
%A Kaim, Wolfgang.
%D 2012
%J Dalton Transactions
%K EPR MQ3 NIR deriv electronic osmium quinone ruthenium
%N 29
%P 8913--8921
%R 10.1039/c2dt30846k
%T UV-vis-NIR and EPR characterization of the redox series MQ32+,+,0,-,2-, M = Ru or Os, and Q = o-quinone derivative
%V 41
%X The neutral title compds. with Q = 3,5-di-tert-butyl-o-quinone or 4,6-di-tert-butyl-N-phenyl-o-iminobenzoquinone (Qx) were studied by UV-visible-NIR spectroelectrochem. and by EPR spectroscopy in the case of the odd-electron monocation and monoanion intermediates. Supported by DFT and TD-DFT calcns., the results indicate stepwise electron removal from predominantly ligand-based delocalized MOs on oxidn. whereas the stepwise electron uptake on redn. involves unoccupied MOs with considerably metal-ligand mixed character. In both cases, the strong near-IR absorption of the neutral precursors diminishes. In comparison to the ruthenium series, the osmium analogs exhibit larger transition energies from enhanced MO splitting and a different EPR response due to the higher spin-orbit coupling. The main difference between the quinone (1n, 2n) and corresponding monoiminoquinone systems (3n, 4n) is the shift of $\sim$0.6 V to lower potentials for the monoimino analogs. While the absorption features do not differ markedly, the EPR data reflect a higher degree of covalent bonding for the complexes with monoimino ligands. on SciFinder(R)
@article{Das.2012f,
abstract = {The neutral title compds. with Q = 3,5-di-tert-butyl-o-quinone or 4,6-di-tert-butyl-N-phenyl-o-iminobenzoquinone (Qx) were studied by UV-visible-NIR spectroelectrochem. and by EPR spectroscopy in the case of the odd-electron monocation and monoanion intermediates. Supported by DFT and TD-DFT calcns., the results indicate stepwise electron removal from predominantly ligand-based delocalized MOs on oxidn. whereas the stepwise electron uptake on redn. involves unoccupied MOs with considerably metal-ligand mixed character. In both cases, the strong near-IR absorption of the neutral precursors diminishes. In comparison to the ruthenium series, the osmium analogs exhibit larger transition energies from enhanced MO splitting and a different EPR response due to the higher spin-orbit coupling. The main difference between the quinone (1n, 2n) and corresponding monoiminoquinone systems (3n, 4n) is the shift of $\sim$0.6 V to lower potentials for the monoimino analogs. While the absorption features do not differ markedly, the EPR data reflect a higher degree of covalent bonding for the complexes with monoimino ligands. [on SciFinder(R)]},
added-at = {2022-06-15T11:26:56.000+0200},
author = {Das, Atanu Kumar and Huebner, Ralph and Sarkar, Biprajit and Fiedler, Jan and Zalis, Stanislav and Lahiri, Goutam Kumar and Kaim, Wolfgang.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2201117e52a340571d8bbf96aa411d50f/huebleriac},
doi = {10.1039/c2dt30846k},
interhash = {4a1d3e88caef0b588410c99193fe6c14},
intrahash = {201117e52a340571d8bbf96aa411d50f},
issn = {1477-9226},
journal = {Dalton Transactions},
keywords = {EPR MQ3 NIR deriv electronic osmium quinone ruthenium},
number = 29,
pages = {8913--8921},
timestamp = {2022-06-15T09:26:56.000+0200},
title = {UV-vis-NIR and EPR characterization of the redox series [MQ3]2+,+,0,-,2-, M = Ru or Os, and Q = o-quinone derivative},
volume = 41,
year = 2012
}
