Structure of the complex UCl4∙2DMF by vibrational infrared spectroscopy and density functional theory

Abstract

Structural models are designed and spectral characteristics are computed based on DFT calculations for a complex of UCl 4 with two molecules of DMF (UCl 4 ⋅2DMF). The calculations were carried out using a B3LYP hybrid functional in the LANL2DZ effective core potential approximation for the uranium atom and an allelectron basis set, cc-pVDZ, for all other atoms with partial force-field scaling. Two structural variants were found for the complex. The first structure is more stable, has C i symmetry, and is characterized by trans arrangement of ligands. The energy of the second structure of C 2 symmetry (with cis arrangement of ligands) is greater by 46 kJ/mol. The formation of the complex is shown to be accompanied by significant changes in the structure of UCl 4 . The obtained spectral characteristics are analyzed and compared with experimental data. The adequacy of the proposed models and the agreement between calculation and experiment are demonstrated.

2D Porphyrinic Metal-Organic Frameworks Featuring Rod-Shaped Secondary Building Units

“…Finally, bands at ca. 1600 cm −1 can be attributed to C=O stretching vibrations from the coordinated and constitutional DEA solvent molecules within PROD-1 and PROD-2 [ 103 ].…”

Quantum Chemical Simulation of the Interaction of Functional Groups in Polyurethanes with 3d-Metal Ions During Their Extraction from Aqueous Solutions

“…A possible mechanism for this interaction, which may be elucidated by vibrational IR spectroscopy and quantum chemical simulation, is complex formation. In previous work [8][9][10], we used quantum chemical calculations and spectroscopic measurements to interpret the vibrational spectra of PU structural fragments [8], constructed structural models, and interpreted the vibrational spectra of uranium complexes with polar organic ligands [9,10]. Calculations carried out using the density functional theory (DFT) demonstrated the suitability of the models of the structure of fragments of PU and complexes as well as the accord of the experimental structural and spectral data.…”

“…The frequencies of the most characteristic vibrations localized in the urethane or urea groups are given in Table 2. Since the vibrations of the terminal groups such as OH, C=O, and NH have signifi cant anharmonicity, the calculated frequencies of the vibrations of these groups in the harmonic approximation on the theory level used are overestimated by ~4-5% relative to the experimental values for the free forms [8][9][10]. We note that, in contrast to the localized vibrations of the terminal groups, the stretching vibrations of the -O-C(O)-N-fragment of the urethane group and the -N-C(O)-N-fragment of the urea group are delocalized.…”