Effect of co-ligands on photoredox pathways in Cr(III) oxalate complexes

doi:10.1016/j.jphotochem.2012.09.013

Effect of co-ligands on photoredox pathways in Cr(III) ...

Bibliographic description

punktacja MNiSW [2012 A]: 25

title:	Effect of co-ligands on photoredox pathways in Cr(III) oxalate complexes
author:	Wiśniewska Joanna, Marai Hasan, Karocki Andrzej, Stopa Grzegorz , Kita Ewa, Stasicka Zofia
Journal title:	Journal of Photochemistry and Photobiology. A, Chemistry
volume:	250
date of publication:	2012
pages:	78-84
ISSN:	1010-6030
eISSN:	1873-2666
DOI:	10.1016/j.jphotochem.2012.09.013
language:	English
Journal language:	English
abstract in english:	The photochemical behaviour of some mixed ligand chromium(III) complexes with amino acids, [Cr(C 2 O 4 ) 2 (Aa)] n − (where Aa = alanine, valine, serine, cysteine, asparagine, aspartic acid) was studied. The attention was focused on the photoredox mode, which proceeded via inner- or intramolecular path- way yielding Cr(II) species and hydrated electrons, respectively. The secondary thermal processes were dependent on the O 2 presence and solution pH: (i) in oxygen-free media the regeneration of substrate and photoaquation induced by the Cr(III) → Cr(II) reduction were observed, (ii) in the presence of O 2 both Cr(II) and ligands were oxidized and the former was transformed not only into Cr(III) but also to Cr(VI) (provided that pH > 7). Prolonged irradiation resulted in photoreduction of Cr(VI) accompanied by pho- todegradation of oxalate and/or amino-acid ligands. The photoreaction modes were independent of the co-ligand nature, but the secondary reaction rates and efficiencies were sensitive both to the co-ligand nature and its side substituent. Environmental consequences of the chromium photoreduction are dis- cussed in the paper: the parameters affecting production and consumption of Cr(VI) are analysed, and the tools of controlling the photoredox behaviour of the Cr(III) and Cr(VI) compounds are suggested.
keywords in english:	chromium(III) complexes, oxalate, chromate(VI), amino acid, photoinduced electron transfer, photoreduction
departmental parameterization:	25
affiliation:	Wydział Chemii : Zakład Chemii Nieorganicznej
type:	journal article
subtype:	academic paper