Mononuclear chelating diselenito complexes of platinum(II) and the crystal structure of bis-triphenylphosphine(diselenito-O,O′)platinum(II): Preference for hard versus soft ligands of the cis-Pt(PPh3)2 moiety?

An OO′ chelating diselenito is found in the X-ray structure of [Pt(PPh3)2(Se2O5)]. The possible preference of the cis-Pt(PPh3)2 moiety towards O, rather than softer donor ligand atoms, is briefly discussed on the basis of other examples.