Synthesis And Properties Of The Ln(â…¢)-grafting Conjugated Polymer Based On Chromaticity

The conjugated polymer with special functionalities and properties have made progress on solid-state opto-electronic materials and molecular devices, such as nonlinear optical materials, organic solar cells (OSCs), organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs) and fluorescence sensor, etc. The notable advantage of well-designed conjugated polymers, such as ultra thin, lightweight, low distribution cost, mechanical flexibility and easy fabrication as uniform film, is major reason that can ensure their widespread application in novel materials. The conjugated polymers can be synthesized through the classic Heck, Suzuki and Still cross coupling. However, they also have some intrinsic drawbacks: short lifetimes, low quantum yields,Ï€-stack induced aggregated quenching and poor color purity which limit their applications as optoelectronic materials. Therefore, the conjugated polymer incorporating feature metal ions as the optoelectronic materials have attracted considerable attention in the past few years.In this dissertation, the researches focused on the designed and synthesis the chiral conjugated polymer as fluorescence senor and Eu(â…¢)-grafting polymer as tuning chromaticity material, respectively.1. Polymer-Based Fluorescence Sensor Incorporating Perylenyl-salen Moieties for Hg2+Detection The chiral conjugated polymer sensor incorporating (R.R)-salen and perylenyl moieties in the main chain backbone was obtained by the polymerization of1.7-bis((3-formyl-4-hydroxyphenyl)ethynyl)perylene-3,4:9.10-tetracarboxylic tetrabu-tylate with (R.R)-1,2-diaminocyclohexane via nucleophilic addition-elimination reaction. The polymer sensor emits the fluorescence situated at635nm due to the introduction of strong fluorophore perylenyl group. Compared with the other cations including Na+. K+, Ca2+. Ag+. Ni2+. Cd2+, Pb2+, Cr3+Al3+, Fe3+, Co2+, Zn2+,only Hg2+can lead to the most pronounced response of the polymer sensor as high as26-fold fluorescence enhancement without interference from other metal ions. More importantly, the fluorescent color of the polymer sensor displays obvious change from red to bright yellow upon addition of Hg2+. which is easily detected by naked eyes. The fluorescence enhancement response behavior of sensor on Hg2+can be attributed to the combination of the ICT and PET mechanism.2. Synthesis and Properties of the Eu(â…¢)-grafting Conjugated Polymer Based on Tuning ChromaticityThe conjugated polymer was synthesized by the polymerization of5,5’-divinyl-2,2’-bipyridine and N,N’-bis(octyl)-1,7-dibromoperylene diimide via Heck cross coupling. The conjugated polymer was directly coordinated with Eu(TTA)3·2H2O/Gd(TTA)3·2H2O to form the corresponding Eu(â…¢)/Gd(â…¢)-grafting conjugated polymer, respectively. Interestingly. Eu(â…¢)-grafting polymer exhibited exceptional emissive properties which can be tuned by the selected excitation wavelengths. For example, a green fluorescence was obtained when Eu(â…¢)-grafting polymer excited at440nm, whereas a characteristic emission of Eu(â…¢) at613nm was observed when excited at365nm. The characteristic emission of5Doâ†'7F2transition was lit by an effective photoinduced energy transfer process between the polymer and Eu(TTA)3moiety. However. The emission of Gd(â…¢)-grafting polymer can not be tuned by the selected excitation wavelengths. The rare excitation induced emission color change of Eu(â…¢)-grafting polymer has led to a better understanding the energy transfer process between the conjugated polymer and Eu(TTA)3moiety.3. Tuning Chromaticity Based on the Zn(â…¡)-Eu(â…¢)-grafting Conjugated PolymerA novel Salen-Zn(â…¡)-containing conjugated polymer was prepared by the reaction of the monomer5,5’-divinyl-2,2’-bipyridine and Salen-Zn(â…¡) via Heck cross coupling. The bipyridyl moiety in Zn(â…¡)-containing polymer can further incorporate with Eu(TTA)3·2H2O to generate the corresponding Zn(â…¡)-Eu(â…¡)-grafting polymer. Interestingly. Zn(â…¡)-Eu(â…¢)-grafting polymer exhibited exceptional dual emissive properties which can be tuned by the selected excitation wavelengths. For example, an orange fluorescence can be obtained when Zn(â… )-Eu(â…¢)-grafting polymer excited at430nm, whereas a characteristic emission of Eu(â…¢) at613nm was observed when excited at345nm. The characteristic emission of5Doâ†'7F2transition was lit by an effective photoinduced energy transfer process between Zn(â…¡)-containing polymer and Eu(TTA)3moiety. The rare excitation induced emission color change of Eu(â…¢)-Zn(â…¡)-grafting polymer has led to a better understanding of the effective energy transfer process between the Zn(â…¡)-containing polymer and the Eu(TTA)3moiety.4. Circularly Polarized Luminescence and Tuning Chromaticity of the Eu(III)-grafting Conjugated PolymerTwo novel chiral conjugated polymers were prepared from the corresponding monomers with (R,R)-1,2-aminoeyclohexane via a nucleophilic addition-elimination reaction. Eu(TTA)3·2H2O was directly coordinated with chiral conjugated polymers to afford the corresponding Eu(â…¢)-grafting polymers. Photoexcitation of one Eu(III)-grafting polymer produced pink color emission as result of the combination of partial blue self-emission along with the red fluorescence from the Eu(TTA)3moiety, whereas the other showed an exclusively red color emission from the Eu(â…¢) ion center due to almost complete excitation energy transfer from the macromolecular chain to the Eu(TTA)3moiety. The choice substitution of phenyl derivative of the polymer played a crucial role on the efficient energy transfer from the polymer chain to Eu(â…¢) ion center. Meanwhile, the largest value of the dissymmetry factor (glum) for the lower-energy component of the5Doâ†'7F4transition of one Eu(â…¢)-grafting conjugated polymer can reach as high as+1.4084and is the best result for the reported chiral complexes of europium. So we expect that the designed Eu(â…¢)-grafting chiral polymer could be fabricated as the color tunable emitting materials for the luminescence device with efficiently CPL activity, whereas the other exhibits the largest gium (+0.0464) centered at434nm.