GI-XAFS

Indicates single crystal substrates and GI-EXAFS or UHV XAFS experiments. All other samples are high surface area powdered solids or bacterial, fungal, or organic substances. 

The reaction of Cr(VI) with bovine serum albumin (BSA) at pH 7.4 results in the formation of Cr(V) species (detected by EPR spectroscopy, gi o = 1.9790) (411). The reported giso value is characteristic of hve-coordinate Cr -oxo complexes with 1,2-diolato coordination (I in Chart 1 Section II.A.2) (12, 18, 27). This complex, however, may be an artifact due to the presence of trace carbohydrates in BSA, as no signihcant EPR signals were observed during the reactions of high purity BSA with Cr(VI) (412). Photocatalyzed reactions of Cr(VI) with amino acids (Gly or Ala) or with small peptides (Gly or Ala , n = 3-5) in methanol solutions led to the formation of relatively stable Cr -amino acid(peptide) complexes (such as II in Chart 1), characterized by EPR spectroscopy and electrospray mass spectrometry (22, 23, 34). An EPR silent Cr -Ala dimer (III in Chart 1) has been isolated and characterized by XAFS spectroscopy this is the first structurally characterized Cr -amino acid complex... 

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