DIFFERENTIATING BETWEEN MONODENTATE AND BIDENTATE CARBOXYLATE LIGANDSCOORDINATED TO URANYL IONS USING EXAFS

We have investigated the U L-III-edge EXAFS of two carboxylato uranyl complexes of known structure to explore the possibilty of differentiat ing between monodentate and bidentate coordinated carboxylate ions. Th e interpretation of EXAFS results from uranyl complexes with carboxyla te ions based solely on axial and equatorial bond lengths can be incon clusive; information from further-distant shells is often needed. Mult iple scattering (MS) pathways along the O=U=O unit and in coordinating chelating or monodentate carboxylate groups can make substantial cont ributions to the EXAFS. Therefore, MS pathways were calculated using F EFF6 [1] and considered in the data analysis. EXAFS results are compar ed to XRD data reported in the literature.