Synthesis\nof Silver(I) Complexes through In Situ Reactions\nof dppeda with dmp in the Presence of Silver Halides for Photocatalysis

Due\nto the unique photosensitivity of silver compounds, they exhibit\ngood photocatalytic activity as photocatalysts in the degradation\nof water pollutants. However, silver compounds have poor cycling stability\nand are prone to decomposition and reaction under light to form metallic\nsilver, which greatly limits their practical application. Herein,\na (2-(2-(diphenylphosphaneyl)ethyl)-9-methyl-1.10-phenanthroline (PSNNP))\npincer ligand was designed for stabilizing the central metal. The\nin situ-formed PSNNP ligand could be readily generated in one pot\nwith the participation of silver halides. The reaction of silver halides\nwith dppeda (<i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-tetra(diphenylphosphanylmethyl)ethylene\ndiamine) in the presence of dmp (2,9-dimethyl-1,10-phenanthroline)\nin acetonitrile afforded complexes Ag<sub>2</sub>X<sub>2</sub> (PSNNP)<sub>2</sub> (complexes <b>1</b>, <b>2</b>) (X = Cl, Br).\nSingle-crystal X-ray diffraction shows that the tridentate coordination\nof the pincer ligand provides strong binding with metal centers and\nleads to high stability of the pincer metal unit. The removal rate\nof rhodamine B (RhB) by complexes <b>1</b> and <b>2</b> can reach up to 100%, demonstrating an excellent photocatalytic\ndegradation performance for organic dyes. The important effect of\nPSNNP ligands on photocatalytic properties after coordination with\ncentral metals was studied through experiments and discrete Fourier\ntransform (DFT) calculations. The photocatalytic reaction mechanism\nof complexes <b>1</b> and <b>2</b> was also studied. This\nresult provides an effective pathway for the first synthesis of PSNNP\nand interesting insights into photocatalytic degradation chemistry.