Synthesis And Properties Of Boron Hybid Functional Polymers

Organic conjugated polymers have attracted tremendous scientific and industrial interest due to their remarkable optical/electrochemical properties. In comparison with their inorganic counterparts, the main advantages of the organic conjugated polymers are their lightweight, flexible nature, solution processability and tunable properties. Conjugated polymers with electron donor-π-acceptor (D-π-A) architecture are particularly attractive due to the facile tunability of their electronic structure of the main chain. They are used in a wide range of applications, including solar cells, organic light-emitting diodes, organic field-effect transistors, and sensors. In this dissertation, the studies focused on the synthesis of boron hybrid organic conjugated polymers via palladium-catalyzed coupling reactions, their optical/electrochemical properties, and the consistency between the experimentally determined band gaps and the theoretically calculated ones. The main works are as follows:1. Aza-BODIPY-based D-π-A Conjugated Polymers with Tunable Band Gap: Synthesis and Near-Infrared EmissionThree aza-borondipyrromethene (Aza-BODIPY)-based D-π-A type polymers P1, P2, and P3 could be synthesized via Pd-catalyzed Sonogashira coupling reaction, respectively. These resulting aza-BODIPY-based conjugated polymers show narrow near-infrared emission in the range of 742-763 nm. The D-π-A polymers can also exhibit an interesting trend of visible color (cyan for P1, green for P2, and light green for P3) in solution by the choice of different monomers structures. The band gaps of the alternating polymers can be tuned in the range 0.96-1.14 eV by using three different donors.2. Near-Infrared Emission of Novel Bent-core V-shape Conjugated Polymers based on B,O-Chelated Azadipyrromethene StructureThree novel polymers with bent-core V-shape chain backbone, P4, P5, and P6, were synthesized by Pd-catalyzed Sonogashira coupling reaction. The resulting conjugated polymers exhibit narrow near-infrared (NIR) emission over 820 nm with tunable band gaps in the range of 0.99-1.21 eV. Interestingly, there is a linearly proportional relationship between the experimentally determined energy levels (cyclic voltammetry (CV)) and the theoretically calculated ones for the HOMOs and LUMOs of these polymers.3. Synthesis and Tunable Chiroptical Properties of Chiral BODIPY-based D-π-A Conjugated PolymersThree chiral BODIPY-based polymers P7, P8, and P9 could be synthesized via Pd-catalyzed Sonogashira coupling reaction, respectively. Three chiral BODIPY-based conjugated polymers can exhibit red fluorescent emission centered at around 624-650 nm with tunable band gaps in the range of 1.56-1.96 eV, respectively. Interestingly, compared with the anisotropy (r=0.005) of chiral BODIPY small molecule as the counterpart, three chiral polymers can exhibit high r (up to 0.10 for P7).4. Large Stokes Shift Chiral Polymers Containing (R,R)-Salen-based Binuclear Boron Complex:Synthesis, Characterization, and Fluorescence PropertiesTwo novel chiral fluorescence polymers P10 and Pll incorporating (R,R)-salen-based binuclear boron complex in the main chain backbone were synthesized via Pd-catalyzed Sonogashira coupling reaction, respectively. Both two chiral polymers show notable anisotropic fluorescence property (r=0.08), respectively. The two chiral polymers can exhibit high fluorescence quantum yields (up to 44% and 52%) with large Stokes shifts over 90 nm.