Chisholm, Malcolm H., D'Acchioli, Jason S., Hadad, Christopher M. and Patmore, Nathan J. (2005) Studies of oxalate-bridged MM quadruple bonds and their radical cations (M = Mo or W): on the matter of linkage isomers. Dalton Transactions (10). pp. 1852-1857. ISSN 1477-9226
Metadata only available from this repository.Abstract
Electronic structure calculations employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) have been carried out on the model complexes {[(HCO2)3M2]2(μ-O2CCO2)}0/+ (M = Mo or W) in D2h symmetry, where the oxalate bridge forms either five- or six-membered rings with the M2 centres; the complexes are hereafter referred to as μ(5,5)0/+ and μ(6,6)0/+, respectively. The calculations predict that the neutral complexes should exist as the μ(5,5) linkage isomer, while the radical cations favour the μ(6,6) isomer by ca. 4–6 kJ mol−1. For the μ(5,5) isomers, the rotational barriers about the oxalate C–C bond have been calculated to be 15.9 and 27.2 kJ mol−1 for M = Mo and W, respectively. For the cationic μ(5,5)+ isomers the barrier is higher, being 36.8 and 50.6 kJ mol−1 for M = Mo and W, respectively. The calculated Raman and visible near-IR spectra for the μ(5,5)0/+ and μ(6,6)0/+ are compared with experimental data obtained for the {[(tBuCO2)3M2]2(μ-O2CCO2)}0/+ complexes, hereafter referred to as M4OXA0/+ (M = Mo or W). The experimental data more closely correlate with that calculated for the μ(5,5)0/+ linkage isomers, and the 13C-NMR spectrum of the mixed metal complex Mo2W2OXA indicates the presence of the 5-membered oxalate-bridged species (JCC = 100 Hz).
Item Type: | Article |
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Subjects: | Q Science > Q Science (General) Q Science > QD Chemistry |
Schools: | School of Applied Sciences |
Related URLs: | |
Depositing User: | Sharon Beastall |
Date Deposited: | 03 Apr 2014 07:42 |
Last Modified: | 28 Aug 2021 11:36 |
URI: | http://eprints.hud.ac.uk/id/eprint/19963 |
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