A new heteroleptic cuprous polymer constructed by a cyanopyridine ligand exhibiting a supramolecular framework structure and luminescence

Luminescent cuprous complexes are of great importance among coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title heteroleptic cuprous polymer solvate, catena-poly[[[(9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane)-κ²P,P'](μ-pyridine-3-carbonitrile-κ²N¹:N³)copper(I)] hexafluorophosphate dichloromethane trisolvate], {[Cu(C₆H₄N₂)(C₃₉H₃₂OP₂)]PF₆·3CH₂Cl₂}_n, conventionally abbreviated as {[Cu(3-PyCN)(Xantphos)]PF₆·3CH₂Cl₂}_n, where Xantphos and 3-PyCN represent (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) and pyridine-3-carbonitrile, respectively, has been described. In this polymer solvate, the asymmetric unit consists of three dichloromethane solvent molecules, a hexafluorophosphate anion and a polymeric heteroleptic cuprous complex cation, in which the cuprous centre is in a CuP₂N₂ tetrahedral coordination and is coordinated by two P atoms from the Xantphos ligand and two N atoms from two 3-PyCN ligands (the pyridyl and cyano N atoms). It is through the connection of the μ₂-bridging 3-PyCN ligand that these cuprous centres are linked into a one-dimensional helical chain structure. The chains are further assembled through C-H...π interactions to form a supramolecular metal-organic framework containing solvent-accessible channels. The UV-Vis absorption and photoluminescence properties of this heteroleptic cuprous polymer have been studied on as-synthesized samples. Its luminescence emission should mainly originate from the metal-to-ligand charge transfer excited state.