LAUSR

Abstract Cu(II) cations in the presence of diamine ligands such as tetramethylethylendiamine (TMEDA) react with Na2SeO3 to produce the heteroleptic selenite copper compound of formula [Cu3(TMEDA)3(SeO3)2(H2O)4](NO3)2. In the cationic moiety two copper atoms are linked by two selenite anions through the O–Se–O bridge. One of the two bridging selenite anion coordinates to a third copper atom through the third oxygen atom. Reaction of Cd(CH3COO)2·2H2O with Na2SeO3 in the presence of ligand with softer character such as thiourea [(NH2)2CS; tu] or selenourea [(NH2)2CSe; tu] in aqueous solution afforded the complex [{Cd(tu)2SeO3}2], whose structure has been elucidated by X-ray diffraction analysis. It is the first reported example of a molecular cadmium selenite complex. Two cadmium cations stabilized by the coordination of four ancillary thiourea soft ligands, are linked together by two bridging selenite ions through O and O–Se–O bridges. A comparison between the coordination mode of the selenite ion in those cadmium and copper complexes and in inorganic extended CdSeO3 and hydrated CuSeO3 phases is also reported.