Related Experiment Video
Updated: Feb 4, 2026

Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
Light-induced decarboxylation in a photo-responsive iron-containing complex based on polyoxometalate and oxalato
Yan Duan1, João C Waerenborgh2, Juan M Clemente-Juan1
1Instituto de Ciencia Molecular (ICMol) , Universitat de València , c/Catedrático José Beltrán, 2 , 46980 Paterna , Spain . Email: carlos.gimenez@uv.es ;
Abstract:
A new photoresponsive molecular polyanion in which two Fe(iii) ions are simultaneously coordinated by two [A-α-PW9O34]9- polyoxometalate units and two oxalato ligands has been obtained. When irradiated with UV light its potassium salt, 1, exhibits a remarkable photocoloration effect, attributable to the partial reduction of the POM units to give rise to a mixed-valence species. The photoinduced process is intramolecular and involves electron transfer from the oxalato ligands, which partially decompose releasing CO2, towards the Fe(iii) and the POM. This mechanism has been confirmed by DRS, IR, XPS and Mössbauer spectroscopy, magnetism and elemental analysis. An analogous derivative of 1 containing malonato ligands does not exhibit such photoactive behaviour, which is evidence that the oxalate ligand is essential for the photoactivity of 1. To our knowledge, 1 represents the first POM-based compound in which the photocoloration effect does not require the presence of intermolecular short interactions.
Related Concept Videos
Photoreceptors and Plant Responses to Light
Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
Ligand Binding and Linkage
Ligand Binding Sites
Protein-ligand interactions are quite specific; even though numerous potential ligands surround a cellular protein at any given time, only a particular ligand can bind to that protein. Moreover, a ligand binds only to a dedicated area on the surface of the protein, known as the...
Formation of Complex Ions
Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...

