Donor-acceptor modulation of coordination polymers for effective photothermal conversion

Abstract

The targeted construction of donor-acceptor (D-A) materials featuring efficient photothermal (PT) conversion properties has been an attractive but challenging goal. Herein, a new series of coordination polymers (CPs) featuring different PT performances were constructed with flexible linker 1,1′-Ferrocenedicarboxylic acid (FCA) and 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (TPT) as acceptor and donor molecules including coronene and tetrathiafulvalene (TTF). Based on the flexible configurations of FCA ligand and the directing of donor dependent D-A interactions, the structures of TF-1 to TF-3 featuring distinctive dimension were obtained based on Cd(II) ions for investigating the PT property in configurational perspectives. A systematic investigation of the PT properties of the CPs was performed. Notably, TF-3 exhibits the finest PT conversion effect under the irradiation of 560 nm laser, while TF-2 shows optimal PT conversion under 808 nm laser irradiation required for biological PT therapy, illustrating the correlation between the structural and component features of the CPs and their PT performances. Furthermore, Zn(II) as bio-friendly ion was utilized to construct hypotoxic TF-4 that reveals similar structure to that of TF-2 for potential application. Polydimethylsiloxane (PDMS) patches doped with TF-4 exhibits considerable NIR PT conversion effect under 808 nm, represented by the nearly 80 °C temperature increased in 120 s for TF-4@PDMS patch (1.2 wt%) under 0.9 W cm⁻² irradiation, the results of which herein indicate the potential of D-A CPs as versatile platform for the modulation of PT materials.