Synthesis and studies on discrete copper halide clusters derived from pyridyl functionalized P-N ligands

Abstract

Synthesis of two pyridyl functionalized phosphorous based monodentate ligands containing P-N bonds, L1 & L2 i.e. (Ph)2PO(NH-3Py) (3Py = 3-pyridyl) and (Ph)2PO(NH- 4Py) (4Py = 4-pyridyl) were carried out. These ligands were then allowed to react with copper (I) iodide, copper (I) bromide and copper (II) chloride dihydrate at room temperature as well as high temperature. Two isostructural discrete polynuclear clusters (L1)4Cu4I4 and (L2)4Cu4I4 having the Cu4I4L4 type of self-assembly were obtained and shown to have thermochromic behavior. While, L2 on reacting with copper halides at different reaction conditions resulted in a rare type of L4Cu4X6O (X = Cl, Br, I) selfassembly containing oxide ion (O2-) which do not exhibit luminescence. Further, the study of the photocatalytic activity of these complexes was done using MB (methylene blue) degradation. All the complexes obtained were able to degrade MB in the presence of H2O2 at room temperature. However, oxido clusters ((L2)4Cu4X6O) were found to be excellent photocatalysts. Stability of the complexes after MB degradation was confirmed by powder patterns.