Optoelectronic Properties Of Supramolecular Polymers Based On Porphyrin Ternarys

In this paper,we have designed and synthesized a series of porphyrin ternarys with1,3,5-benzenedicarboxamide as the core,and studied their supramolecular self-assembly behaviours.The nonlinear optical properties of the as-formed supramolecular polymers have been studied and their applications in the dye sensitized solar cells?DSSCs?have been explored.We have synthesized three porphyrin ternarys TMA,TMB and TMC with different alkoxyl groups by the condensation reactions of the aminoporphyrin monomers with1,3,5-benzenetricarbonyl trichloride.These different alkoxyl groups drive the porphyrin ternarys to demonstrate different supramolecular self-assembly behaviors in various solvents.The aggregation states of TMA and TMB have been investigated by UV-Vis absorption spectroscopy.It has been found that these molecules exist as monomers in chloroform and toluene,but they started to aggregate to form supramolecular polymers when they reached critical concentrations in cyclohexane.The critical concentration of TMA is 6×10^-7 M.The formation of supramolecular polymers of TMA,TMB and TMC can be visualized by atomic force microscopy?AFM?,which demostrate one-dimensional supramolecular architectures.We have studied the third-order nonlinear optical properties from the model compound of TMC at different concentrations by a Z-scanning method.It was found that the molecule self-assemble in the form of monomer,oligomer and supramolecular polymer whichdemonstrate different nonlinear optical properties.In this way,we can use the nonlinear optical method to monitor the self-assembly process with high sensitivity.We intend to use the porphyrin free base as the starting compound,after a series of reactions,i.e.bromination,reduction,Zn metalation,Heck coupling,condensation with1,3,5-benzenetricarbonyl trichloride,and selective hydrolysis,to obtain porphyrin trimer TMD which self-assemble into supramolecular polymers with carboxyl anchore groups.We intend to study the applications of these well-defined supramolecular polymers as the sensitizers in dye sensitized solar cells.We have synthesized a series of related porphyrin intermediates,but the yield of the Heck coupling reaction was too low to carry out the subsequent steps.