Conformations, structural transitions and visible near-infrared absorption spectra of four-, five- and six-coordinated Cu(II) aqua complexes
2009 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 11, no 3, 508-519 p.Article in journal (Refereed) Published
We have performed Car-Parrinello molecular dynamics simulations at ambient conditions for four-, five- and six-coordinated Cu(II) aqua complexes. The molecular geometry has been investigated in terms of Cu-O, Cu-H bond lengths and O-Cu-O bond angles and compared with earlier experimental measurement results and theoretical calculations. We find that the average Cu-O and Cu-H bond lengths increase with increasing coordination number. We have also observed relatively faster structural transition in the case of five- coordinated complex between trigonal bipyramidal and square pyramidal geometry. This result deviates from the findings of the earlier report (A. Pasquarello et al., Science, 2001, 291, 856) on copper( II) in aqueous solution and we attribute these differences to the neglect of solvent environment in our calculations. The averaged absorption spectra for the copper( II) aqua complexes have been computed using spin-restricted density functional linear response formalism taking 100 snap shots from a trajectory of 0.48 ps. We find that the calculated spectra are significantly different, showing clear features that distinguish each coordination model. Comparison with the experimentally reported absorption spectra is made wherever it is possible and the results obtained favor the distorted fivefold-coordination arrangement for the molecular structure of the Cu(II) ion in aqueous solution.
Place, publisher, year, edition, pages
2009. Vol. 11, no 3, 508-519 p.
MOLECULAR-DYNAMICS SIMULATION; DENSITY-FUNCTIONAL THEORY; GAUSSIAN-BASIS SETS; COPPER CENTERS; SPECTROSCOPIC PROPERTIES; ELECTRONIC-STRUCTURE; HYDRATED IONS; ATOMS LI; CU2+; SOLVATION
IdentifiersURN: urn:nbn:se:kth:diva-8424DOI: 10.1039/b806423gISI: 000262007000008ScopusID: 2-s2.0-58149174187OAI: oai:DiVA.org:kth-8424DiVA: diva2:13739
QC 20100714. Uppdaterad från submitted till published (20100714).2008-05-122008-05-122013-03-13Bibliographically approved