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Lithium-ion batteries dominate the battery field, particularly for electric and hybrid vehicles. Monoclinic Li3V2(PO4)3 has emerged as one of the most promising candidates for the cathode in lithium-ion batteries, offering better environmental safety and lower cost than competing materials. We have used in situ X-ray absorption spectroscopy to characterize the evolution of the vanadium in a Li3V2(PO4)3 cathode as it is cycled electrochemically. These data demonstrate the presence of significant kinetic effects such that the measured electrochemical behavior does not represent the bulk vanadium. When the cell is cycled between 3 and 4.5 V, there are two distinct vanadium species. When the potential is raised above 4.5 V, a third species is observed, consistent with formation of V5+. XANES data for the cathode after 3-4.8 V cycling are consistent with a severely distorted vanadium site, suggesting that lithium-vanadium antisite mixing may be responsible for the electrochemical irreversibility that is seen above 4.5 V.

Polarized time-resolved X-ray absorption near edge structure (XANES) is used to characterize the sequential ballistic excited state dynamics of two B12 vitamers: cyanocobalamin and adenosylcobalamin. Excitation at 550 nm and 365 nm is used to resolve axial and equatorial contributions to the excited state dynamics.

Extended X-ray absorption fine structure (EXAFS) studies of the protein farnesyltransferase (FTase) have been undertaken to determine the structure of the Zn site and to provide further insight into the FTase mechanism. In its resting state, the Zn site is coordinated by a histidine, a cysteine and most likely by a bidentate aspartate with a fourth low-Z ligand presumed to be at a longer distance from zinc.

Research has been conducted on manganese uptake in cyanobacterium Synechocystis sp. PCC 6803. The mechanism of this uptake has been investigated and the results demonstrate that manganese accumulates in the outer membrane, that it is transported via the inner membrane and that the outer membrane allows the cells to overcome transient manganese limitations in the environment.

Results demonstrate that zinc is required for methyltransferase enzyme activity and it tightly binds to the enzyme whereas thiolate binds to the metal center of the enzyme, together forming metal-thiolate bond. Data suggest a zinc-mediated thiol deprotonation in catalysis of methyl group transfer in Methanosarcina barkeri.

Research shows that sub-femtomolar range of zinc(II) is enough to cause half-maximal rate of the transcriptional activity in Zur protein of Escherichia coli. Data indicate that Zur possesses two distinct metal binding sites and the coordination between the two binding sites leads to an exceptional zinc sensitivity.

Research demonstrates that the N-terminal domain of Escherichia coli Ada protein maintains zinc-thiolate center upon methylation. The methylated -Ada/DNA complexes make contacts with N-terminal Ada but not with DNA. Data indicate that methylation affects DNA binding and transcriptional activation.

Research reveals that selenohomocysteine addition to N-terminal fragment of cobalamin-dependent and cobalamin-independent methionine synthases results in changes at the near-edge structure of zinc X-ray absorption. Data further indicate that Lewis acidity of the zinc sites are electrostatically buffered by the zinc-cysteine interaction.

Heme in human cystathionine beta-synthase has been studied using X-ray absorption and electron paramagnetic resonance spectroscopies. Results are consistent with the presence of five nitrogens and a sulfur ligand. The axial ligands are likely cysteinate and imidazole in ferric cystathionine beta-synthase. The transsulfuration reaction catalyzed by cystathionine beta-synthase is one of two major metabolism paths for mammal homocysteine.

Cys643, Cys726, and His641 are three of the four zinc ligands in Cobalamin-independent methionine synthase from E. coli. Binding of zinc and homocysteine are not sufficient for enzyme activity.

The article discusses the use of [{Mn (super)IV (salpn)} (sub)2 (mu-O,mu-OCH (sub)3)](CF (sub)3 SO (sub)3) as a probe of protonation on the reactivity of [Mn (super)IV (mu-O)] (sub)2. Experiments have been conducted to demonstrate that methylation of an oxo bridge in a transition metal dimer is analogue for protonation.

XANES measurements on gold-bearing arsenian pyrite from the Twin Creeks Carlin-type gold deposits show that gold is present as both [Au.sup.0] and [Au.sup.I+] and arsenic is present at [As.sup.I-]. [Au.sup.0] is attributed to sub-micrometer size inclusions of free gold, whereas [Au.sup.I+] is attributed to gold in the lattice of the arsenian pyrite. STEM observations suggest that [As.sup.I-] is probably concentrated in angstrom-scale, randomly distributed layers with a marcasite or arsenopyrite structure. Ionic gold ([Au.sup.I+]) could be concentrated in these layers as well, and is present in both twofold- and fourfold-coordinated forms, with fourfold-coordinated [Au.sup.I+] more abundant. Twofold-coordinated [Au.sup.I+] is similar to gold in [Au.sub.2]S in which it is linearly coordinated to two sulfur atoms. The nature of fourfold-coordinated [Au.sup.I+] is not well understood, although it might be present as an Au-As-S compound where gold is bonded in fourfold coordination to sulfur and arsenic atoms, or in vacancy positions on a cation site in the arsenian pyrite. [Au.sup.I+] was probably incorporated into arsenian pyrite by adsorption onto pyrite surfaces during crystal growth. The most likely compound in the case of twofold-coordinated [Au.sup.I+] was probably a tri-atomic surface complex such as [S.sub.pyrite]-[Au.sup.I+]-[S.sub.bi-sulfide]H or [Au.sup.I+]-S-[Au.sup.I+]. The correlation between gold and arsenic might be related to the role of arsenic in enhancing the adsorption of gold complexes of this type on pyrite surfaces, possibly through semiconductor effects.

A study on the catalytically active Mn(III)/Mn(III) binuclear site of oxidized manganese catalase (OxMnCAT) and its interaction with azide is presented. Azide has the same electronic structure as that of hydrogen peroxide. Absorption, MCD and resonance Raman measurements have been undertaken on synthetic complexes having mu-oxo-di-mu-carboxylato-bridged dimanganese(III) units used in modeling the active site of OxMnCAT. Results show that the active site is made up of two ferromagnetically coupled five-coordinate Mn(III) ions linked by a hydroxo bridge.