@article {Martin-Diaconescu2009,
	title = {Effects of hyperconjugation on the electronic structure and photoreactivity of organic sulfonyl chlorides.},
	journal = {Inorg. Chem.},
	volume = {48},
	number = {3},
	year = {2009},
	month = {feb},
	pages = {1038{\textendash}44},
	publisher = {The University of British Columbia, Department of Chemistry, Vancouver, British Columbia V6T 1Z1.},
	abstract = {The electronic structure of organic sulfonyl compounds of the form RSO(2)G (G = -Cl, -OH, -CH(3)) is investigated to evaluate the effect of aryl R groups on photocleavage of the S-G bond. Sulfur K-edge X-ray absorption spectroscopy (XAS) provides a direct measure of the empty low-lying molecular orbitals in these complexes and, in combination with DFT calculations, a detailed description of the bonding in these compounds. The presence of an aryl group bound to the sulfonyl moiety has a significant impact on the spectroscopy and electronic structure of the site. The analysis suggests that the SCl(sigma*) orbital is significantly affected by mixing with the aryl pi* manifold. This mixing is dependent upon the nature of G and is most pronounced in the sulfonyl chlorides, where the energy of the SCl(sigma*) orbital is lowered by approximately 0.5 eV. The observed mixing is best described as excited-state hyperconjugation of the aryl pi system into the SCl(sigma*) orbital. The magnitude of the effect can be estimated directly from the S K-edge XAS spectra. These results are discussed in relation to the observed photochemistry of RSO(2)Cl, which is significantly enhanced when R = aryl as compared to alkyl substituents.},
	keywords = {DFT, ELECTRONS, models, MOLECULAR, molecular structure, Organic Chemicals, Organic Chemicals: chemistry, PHOTOCHEMISTRY, Spectrum Analysis, Sulfinic Acids, Sulfinic Acids: chemistry, sulfur redox, XAS},
	issn = {1520-510X},
	doi = {10.1021/ic801665f},
	url = {http://pubs.acs.org/doi/abs/10.1021/ic50073a047 http://www.ncbi.nlm.nih.gov/pubmed/19132932},
	author = {Martin-Diaconescu, Vlad and Kennepohl, Pierre}
}
@article {ISI:000270186500047,
	title = {Influence of oxygenation on the reactivity of ruthenium-thiolato bonds in arene anticancer complexes: insights from XAS and DFT.},
	journal = {J. Am. Chem. Soc.},
	volume = {131},
	number = {37},
	year = {2009},
	month = {sep},
	pages = {13355{\textendash}61},
	publisher = {American Chemical Society},
	abstract = {Thiolate ligand oxygenation is believed to activate cytotoxic half-sandwich [(eta(6)-arene)Ru(en)(SR)](+) complexes toward DNA binding. We have made detailed comparisons of the nature of the Ru-S bond in the parent thiolato complexes and mono- (sulfenato) and bis- (sulfinato) oxygenated species including the influence of substituents on the sulfur and arene. Sulfur K-edge XAS indicates that S(3p) donation into the Ru(4d) manifold depends strongly on the oxidation state of the sulfur atom, whereas Ru K-edge data suggest little change at the metal center. DFT results are in agreement with the experimental data and allow a more detailed analysis of the electronic contributions to the Ru-S bond. Overall, the total ligand charge donation to the metal center remains essentially unchanged upon ligand oxygenation, but the origin of the donation differs markedly. In sulfenato complexes, the terminal oxo group makes a large contribution to charge donation and even small electronic changes in the thiolato complexes are amplified upon ligand oxygenation, an observation which carries direct implications for the biological activity of this family of complexes. Details of Ru-S bonding in the mono-oxygenated complexes suggest that these should be most susceptible to ligand exchange, yet only if protonation of the terminal oxo group can occur. The potential consequences of these results for biological activation are discussed.},
	keywords = {Antineoplastic Agents, Antineoplastic Agents: chemical synthesis, Antineoplastic Agents: chemistry, Antineoplastic Agents: metabolism, AROMATIC, Aromatic: chemistry, DFT, DNA, DNA: metabolism, Drug Design, ELECTRONS, HYDROCARBONS, LIGANDS, metal-based drugs, models, MOLECULAR, Molecular Conformation, ORGANOMETALLIC COMPOUNDS, Organometallic Compounds: chemical synthesis, Organometallic Compounds: chemistry, Organometallic Compounds: metabolism, OXYGEN, Oxygen: chemistry, quantum theory, ruthenium, Ruthenium: chemistry, Spectrum Analysis, Sulfhydryl Compounds, Sulfhydryl Compounds: chemistry, X-Rays, XAS},
	issn = {1520-5126},
	doi = {10.1021/ja903405z},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19719101 http://dx.doi.org/10.1021/ja903405z},
	author = {Sriskandakumar, Thamayanthy and Petzold, Holm and Bruijnincx, Pieter C A and Habtemariam, Abraha and Sadler, Peter J and Kennepohl, Pierre}
}
@article {ISI:000264792600048,
	title = {Redox photochemistry of methionine by sulfur K-edge X-ray absorption spectroscopy: potential implications for cataract formation.},
	journal = {J. Am. Chem. Soc.},
	volume = {131},
	number = {10},
	year = {2009},
	month = {mar},
	pages = {3577{\textendash}82},
	abstract = {The photochemistry of methionine, methionine sulfoxide, and methionine sulfone have been investigated by using sulfur K-edge X-ray absorption spectroscopy to explore the redox photochemical processes under different conditions. Methionine is easily photooxidized to the sulfoxide and the sulfone in the presence of dioxygen. In the absence of oxidant, photoirradiation leads to the one-electron-oxidized cation radical with no further reaction, suggesting that an alternative mechanism for photooxidation of thioethers through direct oxidation is feasible. The photochemistry of methionine sulfoxide allows for independent oxidative and reductive processes. Photoreduction of the sulfoxide leads back to the parent thioether under both aerobic and anaerobic conditions. Photooxidation occurs only under aerobic conditions. In contrast, methionine sulfone is photochemically inert. These results provide new insights into potential photochemical processes that may lead to cataract formation.},
	keywords = {Cataract, Cataract: etiology, METHIONINE, Methionine: chemistry, Oxidation-Reduction, PHOTOCHEMISTRY, Spectrum Analysis, Spectrum Analysis: methods, sulfur redox, XAS},
	issn = {1520-5126},
	doi = {10.1021/ja806946r},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19226173},
	author = {Karunakaran-Datt, Anusha and Kennepohl, Pierre}
}
