Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Emission spectroscopy of uranium(IV) compounds
T2 - a combined synthetic, spectroscopic and computational study
AU - Hashem, Emtithal
AU - Swinburne, Adam N.
AU - Schulzke, Carola
AU - Evans, Rachel C.
AU - Platts, James A.
AU - Kerridge, Andrew
AU - Natrajan, Louise S.
AU - Baker, Robert J.
PY - 2013/4/7
Y1 - 2013/4/7
N2 - Emission spectroscopy has been used for the first time in a spectroscopic study of a family of uranium(IV) halide complexes in non-aqueous media. The room temperature electronic absorption spectra of the simple coordination compounds [Li(THF)(4)][UX5(THF)] (X = Cl, Br, I), [Et4N](2)[UCl6] and UCl4 in THF have been recorded and all transitions assigned with the aid of a comprehensive computational study using CASSCF and CASPT2 techniques. Excitation into a band of f-d and LMCT character followed by energy transfer into the 5f-orbital manifold accounts for the UV-visible radiative transitions observed in the emission spectra, which have been fully assigned as arising from transitions from the 5f(1)6d(1) electronic configuration to envelopes of states arising from the ground state 5f(2) configuration. The bonding in [Li(THF)(4)][UCl5(THF)] has been further elucidated utilising NBO and AIM calculations which describe the nature of the U-Cl bond as predominantly ionic with some dative covalent character and substantial overlap between the Cl 3p orbitals and 5f and 6d orbitals on uranium. These studies indicate that the emission spectral fingerprint of simple U(IV) compounds of O-h, C-4v and C-2v symmetry are similar and characteristic and may be used as a diagnostic tool to assign U(IV) species in solution and by inference, in the environment, in the presence of [UO2](2+).
AB - Emission spectroscopy has been used for the first time in a spectroscopic study of a family of uranium(IV) halide complexes in non-aqueous media. The room temperature electronic absorption spectra of the simple coordination compounds [Li(THF)(4)][UX5(THF)] (X = Cl, Br, I), [Et4N](2)[UCl6] and UCl4 in THF have been recorded and all transitions assigned with the aid of a comprehensive computational study using CASSCF and CASPT2 techniques. Excitation into a band of f-d and LMCT character followed by energy transfer into the 5f-orbital manifold accounts for the UV-visible radiative transitions observed in the emission spectra, which have been fully assigned as arising from transitions from the 5f(1)6d(1) electronic configuration to envelopes of states arising from the ground state 5f(2) configuration. The bonding in [Li(THF)(4)][UCl5(THF)] has been further elucidated utilising NBO and AIM calculations which describe the nature of the U-Cl bond as predominantly ionic with some dative covalent character and substantial overlap between the Cl 3p orbitals and 5f and 6d orbitals on uranium. These studies indicate that the emission spectral fingerprint of simple U(IV) compounds of O-h, C-4v and C-2v symmetry are similar and characteristic and may be used as a diagnostic tool to assign U(IV) species in solution and by inference, in the environment, in the presence of [UO2](2+).
KW - ELECTRONIC-STRUCTURE CALCULATIONS
KW - RAY-ABSORPTION SPECTROSCOPY
KW - DENSITY-FUNCTIONAL THEORY
KW - QUANTUM-CHEMICAL METHODS
KW - ELEMENT-CHALCOGEN BOND
KW - BASIS-SETS
KW - EXCITED-STATES
KW - BIS(KETIMIDO) COMPLEXES
KW - LUMINESCENCE SPECTRUM
KW - TETRAVALENT URANIUM
U2 - 10.1039/c3ra22712j
DO - 10.1039/c3ra22712j
M3 - Journal article
VL - 3
SP - 4350
EP - 4361
JO - RSC Advances
JF - RSC Advances
SN - 2046-2069
IS - 13
ER -