Construction of Zinc-Based Coordination Polymers Integrating Room-Temperature Afterglow and Photochromism Performance

Abstract The tri(pyridin-4-yl)amine (TPA) molecule can be regarded as a satisfactory organic luminophore for the acquisition of optical materials. Hence, by assembling TPA with the zinc ion in the presence of auxiliary carboxylate ligand, two metal–organic coordination polymers [Zn(TPA)(BPDA)(H2O)2]·0.5H2O (1) and [Zn2(TPA)2(PMA)]·3H2O (2) are fabricated (H2BPDA = 4,4’-biphenyldicarboxylic acid; H4PMA = pyromellitic acid) featuring room-temperature phosphorescence (RTP) performance. By virtue of the coordination rigid environment, as well as the directional interaction network, which significantly restricts molecular vibration and rotation, naked-eye visible afterglow luminescence of the two solids is achieved. Moreover, electron transfer (ET)-induced photochromism is detected in the Zn-organic compounds when exposed to UV irradiation. This interesting behavior is attributed to the generation of radicals, which are demonstrated to be the key species responsible for the obvious color change in this work.