Synthesis and characterization of novel tetrahedral copper(I) complexes comprising tridentate PNP-aminodiphosphines and tetradentate PN(X)P-substituted aminodiphosphines (X = O, S)

Two series of novel tetrahedral copper(I) complexes comprising tridentate PNP-aminodiphosphines and tetradentate PN(X)P-substituted aminodiphosphines (X = O, S) have been prepared and characterized by conventional physico-chemical techniques. The first series includes ‘3 + 1’-type complexes comprising an aromatic PNP-aminodiphosphine and acetonitrile or triphenylphosphine. In the second series, the central amine function of the PNP-ligand was substituted with functionalized pendant arms containing ether, hydroxyl or thioether groups to enhance the chelation ability of the ligand. Fully coordinated neutral and cationic complexes were isolated. A preliminary study investigating both the labeling of ⁶⁴Cu with the prototype PN(S)P ligand and the potential cytotoxic activity of the ‘cold’ [Cu(PN(S)P)][BF₄] complex is reported.