@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 {Funk2004,
	title = {X-ray magnetic circular dichroism of Pseudomonas aeruginosa nickel(II) azurin.},
	journal = {J. Am. Chem. Soc.},
	volume = {126},
	number = {18},
	year = {2004},
	pages = {5859{\textendash}66},
	abstract = {We show that X-ray magnetic circular dichroism (XMCD) can be employed to probe the oxidation states and other electronic structural features of nickel active sites in proteins. As a calibration standard, we have measured XMCD and X-ray absorption (XAS) spectra for the nickel(II) derivative of Pseudomonas aeruginosa azurin (NiAz). Our analysis of these spectra confirms that the electronic ground state of NiAz is high-spin (S = 1); we also find that the L(3)-centroid energy is 853.1(1) eV, the branching ratio is 0.722(4), and the magnetic moment is 1.9(4) mu(B). Density functional theory (DFT) calculations on model NiAz structures establish that orbitals 3d(x2-y2) and 3d(z2) are the two valence holes in the high-spin Ni(II) ground state, and in accord with the experimentally determined orbital magnetic moment, the DFT results also demonstrate that both holes are highly delocalized, with 3d(x2-y2) having much greater ligand character.},
	keywords = {Azurin, Azurin: chemistry, circular dichroism, Circular Dichroism: methods, copper, Copper: chemistry, CRYSTALLOGRAPHY, LIGANDS, Magnetics, models, MOLECULAR, Molecular Conformation, NICKEL, Nickel: chemistry, PDF, Pseudomonas aeruginosa, Pseudomonas aeruginosa: chemistry, X-RAY, X-Rays},
	issn = {0002-7863},
	doi = {10.1021/ja036218d},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/15125678},
	author = {Funk, Tobias and Kennepohl, Pierre and Di Bilio, Angel J and Wehbi, William a and Young, Anthony T and Friedrich, Stephan and Arenholz, Elke and Gray, Harry B and Cramer, Stephen P}
}
