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In a previous study [Int. J. Mass Spectrom. 2010; 297: 67-75], the asym. O=U=O stretch (ν3) was measured for anionic uranyl complexes with compn. [UO2(X)3]-, X = Cl-, Br- and I-.  Within this group of complexes, the ν3 frequency red-shifts following the trend I > Br > Cl, suggesting concomitant weakening of the U=O bonds.  However, a value for [UO2(F)3]- was not measured, which prevented a comprehensive comparison of measured ν3 positions to computed frequencies from d. functional theory (DFT) calcns.  Because the shift in ν3 is predicted to be most dramatic when X = F, we revisited these species using IR multiple-photon photodissocn. spectroscopy.  As in our earlier study, a modest red-shift to the ν3 vibration of ∼ 6 cm-1 was obsd. for X = I-, Br-, and Cl-, and the position of the frequency follows the trend I- > Br- > Cl-.  The value measured for [UO2(F)3]- is ∼43 cm-1 lower than the one measured for [UO2(Cl)3]-.  Overall, the trend with respect to ν3 position is reproduced well by computed frequencies from DFT.