Affiliation:
1. Department of Chemistry University of Iowa Iowa City IA 52242 United States
Abstract
AbstractA μ‐peroxido‐bis[di‐triethylamine N‐oxide‐dichloro‐dioxouranium] complex with the formula [(UO2)2O2(ON(CH2CH3)3)4Cl2] (complex 1) was synthesized photochemically from a reaction containing uranyl chloride, triethylamine, and H2O2. The photochemical breakdown of H2O2 yielded ⋅OH radicals that reacted with triethylamine to form triethylamine N‐oxide (TEAO) in situ, which subsequently coordinated to UO22+ cations in a monodentate fashion via the N‐oxide functional groups. Structure determination using single crystal X‐ray diffraction revealed that TEAO ligands also formed intermolecular and intramolecular hydrogen bonds with UO22+ and peroxide moieties, and the intermolecular H‐bonding interactions displayed a temperature dependence with Oyl ‐ ‐ H−C and Oper ‐ ‐ H−C distances shortening at 100(2) K by ca. 0.1 Å. Raman spectroscopy data were collected on single crystals of 1 and peak fitting of these results allowed for assignments of peaks including C−N stretches for TEAO ligands bound to UO22+ cations at 696.8 cm−1, 717.8 cm−1, and 776.5 cm−1, which are redshifted by 30–40 cm−1 when compared to free triethylamine. UO22+ ν1 and O22− ν1 stretches, U−Oper stretches, and notably, U−Cl stretches were all identified as well, with U−Cl modes at 198.9 cm−1 and 212.1 cm−1 substantially redshifted compared to the uranyl chloride starting material.