How counterions affect the solution structure of polyoxoaurates: Insights from UV/Vis spectral simulations and electrospray mass spectrometry
Kondinski A, Vankova N, Schinle F, Jaeger P, Hampe O, Kortz U, Heine T (2014)
Publication Type: Journal article
Publication year: 2014
Journal
Pages Range: 3771-3778
Journal Issue: 23
DOI: 10.1002/ejic.201402494
Abstract
The solution structure of the two presently known polyoxoaurates, [Au 4As4O20]8- (Au4As 4) and [Au4Se4O16]4- (Au4Se4), was elucidated by a combination of time-dependent density-functional-theory (TD-DFT) calculations, experimental UV/Vis spectroscopy, and electrospray ionization mass spectrometry (ESI-MS). The TD-DFT-predicted electronic spectra for molecular models including different numbers of counterions, along with the main Au4As4 and Au4Se4 structural motifs, were analyzed and compared with the experimental UV/Vis spectra of the two polyanions. The performed analysis revealed important structural differences between the arsenate and the selenite derivatives in aqueous solution. For the selenite oxoaurate, the bare Au 4Se4 polyanion itself shows very good agreement between predicted and experimental excitation energies. In contrast, the solution state of the arsenate oxoaurate appears to be best described by a dimeric assembly of the type [Na5Au8As8O40] 11- (Na5Au8As8) with a stoichiometry and structure very similar to those reported for the solid state. Indirect experimental evidence that Na5Au8As8 is the dominant species in aqueous solution is provided by ESI-MS measurements. Our work demonstrates that the combination of experimental UV/Vis spectroscopy and TD-DFT calculations complemented with electrospray mass spectrometry may serve as an alternative strategy for rationalizing the solution chemistry of polyoxometalates, which cannot be studied by conventionally used spectroscopic techniques, such as NMR or EPR spectroscopy. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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How to cite
APA:
Kondinski, A., Vankova, N., Schinle, F., Jaeger, P., Hampe, O., Kortz, U., & Heine, T. (2014). How counterions affect the solution structure of polyoxoaurates: Insights from UV/Vis spectral simulations and electrospray mass spectrometry. European Journal of Inorganic Chemistry, 23, 3771-3778. https://doi.org/10.1002/ejic.201402494
MLA:
Kondinski, Aleksandar, et al. "How counterions affect the solution structure of polyoxoaurates: Insights from UV/Vis spectral simulations and electrospray mass spectrometry." European Journal of Inorganic Chemistry 23 (2014): 3771-3778.
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