Versatile routes to selenoether functionalised tertiary phosphines

New selenoether functionalised tertiary phosphines, based on aryl (2a, 2b) or alkyl (4) backbones, have been synthesised and characterised. P,Se-chelation has been achieved upon complexation to square-planar PtII (3a) or PdII (3b) metal centres. For 3a and 3b, weak non-covalent M◊ ◊ ◊ Se contacts were established using single crystal X-ray crystallography