Synthesis and characterization of poly-phosphane coinage metals complexes and study on the protein ligation and catalysis

A series of coinage metals centered poly-phosphane complexes has been synthesized and characterized under photophysical, chemical and biochemical aspects also in combination with a protein. Poly-phosphane metal complexes possess many properties in the field of luminescence,[1] catalysis, [2] chemo sensing, [3] and of anticancer activity [4]. In this study phosphane ligands containing the carboxylic functional group in ortho or para position of PPh3 have been used. The introduction of this polar group has the double aim either to make more hydrophilic the complexes and to tune the binding ability of the phosphane. In the case of gold(I) complexes, the poly-phosphine compound have been studied in comparison with the corresponding [bis-triphenylphosphine-gold(I)chloride], where the carboxylic group is absent, to evaluate the influence of its presence in the photopysical properties as well as on the interaction with dihydrofolate reductase, a protein involved in cell proliferation, DNA duplication and many other biological functions [5]. Affinity constants have been estimated through quenching of fluorescence studies and inhibition constants have been evaluated through rate constant determination of the reduction of dihydrofolate (H2F) to tetrahydrofolate (H4F) with reduced nicotinamide adenide dinucleotide phosphate (NADPH) as hydride donor. The tests highlighted a catalytic activity of the gold(I) compounds versus the H2F, which is the substrate of the enzyme. A strong effect of the enzyme on the luminescence properties of the gold(I) complexes have been observed. A coinage metals homolog series have been also evaluated as antiproliferative agent by in vitro MTT tests. Scheme. Schematic view of a homolog series of coinage metals complexes under study. References 1. R. Edward, T. Tiekink, J. G. Kang, Coord. Chem. Rev. 2009, 253, 1627-1648 2. David J. Gorin, Benjamin D. Sherry, and F. Dean Toste, Chem. Rev. 2008, 108, 3351–3378 3. X. He, V. W. Yam, Coord. Chem. Rev. 2011, 2111-2123 4. R. Galassi, A.Burini, O. Camille Simon, A. Dolmella, D. Micozzi, S. Vincenzetti, S. Pucciarelli Dalton Trans., 2015, 44, 3043-3056 DOI: 10.1039/C4DT01542H 5.