Suzuki Coupling Polymerization Research Articles

Anthracene and tetraphenylsilane based conjugated porous polymer nanoparticles for sensitive detection of nitroaromatics in water

Conjugated porous polymers (CPPs) are a kind of promising sensing materials for the detection of nitroaromatic compounds, but their sensing applications in aqueous media are limited because of their poor dispersity or solubility in water. In this study, we prepared anthracene and tetraphenylsilane based CPPs named PSiAn by conventional Suzuki coupling and Suzuki-miniemulsion polymerization, respectively. The structure, morphology and porosity of the CPPs were characterized by Fourier Transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), transmission electron microscope (TEM) and N2 sorption isotherm, respectively. Both of the CPPs have porous structure which is beneficial for the adsorption and diffusion of the analytes within them. The particle size of PSiAn nanoparticles prepared by Suzuki-miniemulsion polymerization is 10–40 nm from the TEM image, which facilitates the dispersion in the aqueous phase. Combined with the porosity and nanoparticle morphology, PSiAn nanoparticles realized the efficient photoluminescence (PL) sensing of nitroaromatic explosives in aqueous phase. The limit of detection (LOD) and limit of quantitation (LOQ) of PSiAn nanoparticles for 2,4,6-trinitrophenol (TNP) detection in the pure aqueous phase are 0.33 μM and 1.11 μM, respectively. Meanwhile, the good selectivity and anti-interference in presence of other nitro-compounds were observed. Furthermore, the spike/recovery test for the TNP detection in real water samples by PL sensing based on PSiAn nanoparticles indicates the quantitative recovery of TNP from 100.74 % to 101.00 %. The electrochemical test, ultraviolet–visible absorption spectra, excitation and emission spectra, and time-resolved PL spectra were investigated to explore the PL sensing mechanism. As a result, it is found that the fluorescence inner filter effect might be the predominant quenching mechanism during the detection of nitrophenolic compounds such as TNP and 4-nitrophenol (4-NP).

Redox-Active Benzodithiophene-4,8-dione-Based conjugated microporous polymers for High-Performance faradaic supercapacitor energy storage

Conjugated microporous polymers (CMPs) are attractive materials due to their microporous architecture, modifiable physical–chemical characteristics, and extended π-conjugated structures. However, their low electronic conductivity limits the development of CMPs with high specific capacitance and excellent charge–discharge stability for supercapacitor energy storage. Furthermore, the redox-active moieties in CMPs for innovative electrode materials are still restricted. Herein, for the first time, two novel redox-active benzo[1,2-b:4,5-b']dithiophene-4,8-dione-based conjugated microporous polymers (DBTh-CMPs), namely, DBTh-TPA and DBTh-TPT CMPs, were prepared through the one-pot Suzuki coupling polymerization of 2,6-dibromobenzo[1,2-b:4,5-b']dithiophene-4,8-dione with triboronic-pinacolates. The DBTh-CMPs exhibited outstanding thermal stabilities (Td10: approximately 608.4 °C; char yield: approximately 71.76%) and surface areas (around 551 m2/g). Interestingly, incorporating redox-active DBTh structures into the backbone of the CMPs resulted in promising conductivity, exceptional faradaic energy storage, and efficient charge transfer. The DBTh-CMPs displayed an exceptional three-electrode capacitance of 1823F g−1 at a current density of 0.5 A g−1 with superior stability of 81.75% over 10,000 cycles; such a value is the largest specific capacity documented via the CMP to date. The two-electrode symmetric supercapacitor device by DBTh-TPT CMP showed a specific capacitance of 609F g−1 and a maximum energy density of 84.5 W h kg−1 operating at a power density equal to 500 W kg−1 and a potential of 1.0 V. The present research supplies a viable strategy for developing electrochemical gadgets and future-oriented supercapacitors.

Fluorescence Modulation of Conjugated Polymer Nanoparticles Embedded in Poly(N-Isopropylacrylamide) Hydrogel.

A series of conjugated polymers (CPs) emitting red, green, and blue (RGB) fluorescence were synthesized via the Suzuki coupling polymerization. Polymer dots (Pdots) were fabricated by the reprecipitation method from corresponding CPs, in which the Pdot surface was functionalized to have an allyl moiety. The CP backbones were based on the phenylene group, causing the Pdots to show identical ultraviolet-visible absorption at 350 nm, indicating that the same excitation wavelength could be used. The Pdots were covalently embedded in poly(N-isopropylacrylamide) (PNIPAM) hydrogel for further use as a thermoresponsive moiety in the polymer hydrogel. The polymer hydrogel with RGB emission colors could provide thermally reversible fluorescence changes. The size of the hydrogel varied with temperature change because of the PNIPAM’s shrinking and swelling. The swollen and contracted conformations of the Pdot-embedded PNIPAM enabled on-and-off fluorescence, respectively. Fluorescence modulation with 20 to 80% of the hydrogel was possible via thermoreversibility. The fluorescent hydrogel could be a new fluorescence-tuning hybrid material that changes with temperature.

Structural Geometry Variation of 1,4-Naphthalene-Based Co-Polymers to Tune the Device Performance of PVK-Host-Based OLEDs.

Blue-color-emitting organic semiconductors are of significance for organic light-emitting diodes (OLEDs). In this study, through Suzuki coupling polymerization, three 1,4-naphthalene-based copolymers—namely, PNP(1,4)-PT, PNP(1,4)-TF, and PNP(1,4)-ANT—were designed and synthesized. The variation of comonomers, phenothiazine (PT), triphenylamine substituted fluorene (TF), and anthanthrene (ANT), effectively tuned the emitting color and device performance of poly(9-vinyl carbazole) (PVK)-based OLEDs. Especially, the polymer PNP(1,4)-TF, bearing perpendicular aryl side groups, showed a most twisted structural geometry, which enabled an ultra-high thermal stability and a best performance with blue emitting in PVK-host-based OLEDs. Overall, in this work, we demonstrate a promising blue-color-emitting polymer through structural geometry manipulation.

Strategy to modify the properties of polyfluorene by incorporating dimethoxyl-biphenyl at different type of connection site

Three ortho-, meta-, and para-linked polymers derived from 9,9-dioctylfluorene (FO) and dimethoxyl-biphenyl (DMBP) were designed and synthesized via catalyst-transfer Suzuki coupling polymerization with palladium(0) catalyst as initiator. Compared to PFO, the conjugated polymers of PFO-o-DMBP, PFO-m-DMBP, and PFO-p-DMBP displayed a significantly blued-shifted absorption and emission spectra with the change of the connecting site from ortho-, meta- to para-position, and the varying degrees were ascribed to the different types of steric hindrance of ortho-, meta-, and para-linkage, which partly hinder the intermonomer rotation of the polymer backbone, giving rise to molecular configuration from linear, zigzag to intertwined structure, and resulting in shortened conjugation length. The optical bandgap calculated from the onset of absorption spectra of the three polymers in solid film are all wider than that of the PFO, indicating that the incorporating of dimethoxyl-biphenyl increased the chain-twisting hindrance and influenced the molecular conformation of the copolymer. Systematical investigation of electrochemical and photophysical properties of the conjugated polymers suggests that the incorporation of dimethoxyl-biphenyl via ortho-, meta-, and para-linkage is an efficient and economic way to modify the properties of polyfluorenes.

Efficient polymer solar cells utilizing solution‐processed interlayer based on different conjugated backbones

AbstractThe poor energy conversion efficiency for those polymer solar cells (PSCs) creates an obstacle for their commercialization. Inspired by this issue, two cathode interlayers, PBTBTz‐TMAI and PBTzPh‐TMAI based on benzothiadiazole (BT) and benzotriazole (BTz)‐conjugated or benzene (Ph) and BTz‐conjugated alternating units (both exhibits the same tetravalent amine‐end side chain), were synthesized via Suzuki coupling polymerization and trivalent amine‐end ionization. When PBTBTz‐TMAI and PBTzPh‐TMAI were utilized as cathode interlayers in PSCs, the charge‐carrier transfer from active layer to cathode electrode was significantly improved, accompanied by an optimized exciton dissociation efficiency, primarily attributed to the introduction of tetravalent amine groups. Consequently, the device with PBTBTz‐TMAI exhibited power conversion efficiencies (PCEs) = 8.3 and 10.5% for the PTB7:PC71BM‐based and PBDB‐T:ITIC‐based PSCs, respectively. In parallel, devices with a PBTzPh‐TMAI cathode interlayer (that were established on the active layers of PTB7:PC71BM and PBDB‐T:ITIC) obtained a remarkably superior optoelectric efficiency with PCEs = 8.5 and 10.8%. These findings offer an alternative tactic toward to high efficiency PSCs to meet the increasing energy crisis.

Trace Ir(III) complex enhanced electrochemiluminescence of AIE-active Pdots in aqueous media

Trace Ir(III) complex enhanced aggregation-induced electrochemiluminescence (AIECL) of poly-tetraphenylethene (pTPE) in aqueous media was investigated for the first time. The poly-TPE end-capped by Ir(III) complex (Ir@pTPE) and its corresponding model polymer poly-TPE (Ph@pTPE) could be synthesized by Suzuki coupling polymerization reaction of 1,2-bis(4-bromophenyl)-1,2-diphenylethene ( M-1 ) with 1,2-diphenyl-1,2-bis(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)ethene( M-2 ) and the continuous Suzuki coupling end-capped reaction of poly-TPE-pinacol boronate with (pq)2Ir(pico)Br and bromobenzene, respectively. Subsequently, the corresponding Ir@pTPE Pdots and Ph@pTPE Pdots encapsulated with poly(styrene- co -maleicanhydride) (PSMA) could be obtained by nanoprecipitation method. Compared with Ph@pTPE Pdots, the Ir@pTPE Pdots with a trace amount of Ir(III) complex (1.34‰ of Ir(III) content, wt) could exhibit 9.9-fold enhancement of the electrochemiluminescence (ECL) signal for visual emission. This work provided a novel strategy on designing highly efficient ECL materials based on trace Ir(III)-end capping AIE-active polymer dots.

Bio-inspired multiple complementary hydrogen bonds enhance the miscibility of conjugated polymers blended with polystyrene derivatives

In this study, we prepared bio-inspired multiple-hydrogen-bonded blends of a thymine (T)-functionalized PTC-T conjugated polymer, synthesized through Suzuki coupling polymerization, and an adenine (A)-functionalized polystyrene (PVBA) homopolymer, synthesized through free radical polymerization, in each case applying also alkylene–azide click reactions. The resulting PTC-T/PVBA blends displayed a single glass transition temperature at all blend compositions (as determined using differential scanning calorimetry), suggesting that the miscibility arose because of the strong multiple hydrogen bonding between the A and T groups of the PVBA and PTC-T components, respectively. 1H NMR and FTIR spectroscopy provided evidence for such A–T binary hydrogen bonding in the PTC-T/PVBA miscible domains, both in solution and in the solid state. Furthermore, the incorporation of PVBA into PTC-T affected the photophysical properties of the luminescent film: the physically crosslinked structure formed from the multiple hydrogen bonding interactions improved the quantum yield through phase-miscible behavior.

Highly emissive fluorene and thiophene based π-conjugated A-alt-B copolymers: Synthesis, characterization and electroluminescence properties

Highly soluble and emissive fluorene and thiophene based A-alt-B type π-conjugated polymers, P1 and P2 have been successfully synthesized through Pd(0)-catalyzed Suzuki coupling polymerization by varying alkyl substitution at 3-position of thiophene. The synthesized cyan-emissive fluorene based π-conjugated polymers have been unambiguously characterized by various spectroscopic tools such as FTIR, multinuclear NMR as well as tetradetector GPC having molecular weight (Mn) 18.2 and 20.8 kDa with the polydispersity indices of 1.32 and 1.35 respectively. The detailed thermal, electrochemical, photophysical and electroluminescence properties of the polymers have been investigated. The highly emissive nature of the synthesized polymers even in solid state prompted us to explore its application as active materials in organic light emitting diodes (OLEDs). The electroluminescence properties of the obtained materials are studied by fabricated the device using the configuration ITO/PEDOT:PSS (50 nm)/P1-P2 (80 nm)/BCP (40 nm)/Al (100 nm). P1 and P2 exhibit bright cyan electroluminescence with CIE of (0.19, 0.29) and (0.21, 0.31) respectively with relatively lower onset voltage of 4 V.

Poly(benzodithieno-imidazole-alt-carbazole) based π-conjugated copolymers: Highly selective and sensitive turn-off fluorescent probes for Hg2+

In this work, highly emissive and soluble π-conjugated poly(benzodithieno-imidazole-alt-carbazole) π-conjugated copolymers (P1 and P2) have been synthesized through Pd(0)-catalyzed Suzuki coupling polymerization protocol from the corresponding monomers. For solubilizing in common organic solvents, heptyl (in P1) or 2-(2-(2-methoxyethoxy)ethoxy)ethyl (in P2) substituents have been introduced at benzodithieno-imidazole and 9-position of carbazole unit. The well-defined and soluble π-conjugated polymers have been characterized by multinuclear NMR spectra as well as by tetradetector GPC studies showing molecular weight (Mn) of 16.5 and 14.3 kDa with the polydispersity indices of 1.36 and 1.31 respectively. The emissive π-conjugated polymers show remarkable selectivity and sensitivity towards Hg2+ ion as turn-off fluorescent probes as a result of molecular wire effect, without interference by other competing metal ions. The detailed photophysical and sensing studies have been demonstrated to understand the insight of polymer-metal ion interaction which is responsible for selective fluorescence quenching of the π-conjugated polymers. DFT studies have been performed to gain the insight of the electronic properties of the sensor by determining the frontier molecular orbitals and the HOMO-LUMO energy levels for a model probe (M1). The polymeric probes (P1 and P2) are reversible in nature, and can also act as secondary sensors for S2-. The limit of detection of the polymer probes towards Hg2+ is found to be in the range of 40–50 ppb with high association constant in the order of 105 M−1 suggesting its high applicability as chemosensor for Hg2+. The polymers have also been explored as thin film polymeric sensor towards Hg2+ to demonstrate its practical utility.

Donor-Acceptor Conjugated Polymer Dots for Tunable Electrochemiluminescence Activated by Aggregation-Induced Emission-Active Moieties.

Low-potential electrochemiluminescence (ECL) luminophores with excellent ECL behavior have attracted considerable interest in biological analysis. Herein, we describe the synthesis of two aggregation-induced emission (AIE)-active conjugated polymers with a donor-acceptor (D-A) system via a Suzuki coupling polymerization reaction. The intramolecular D-A pairs enhanced their luminescence intensity in aggregate states, which was beneficial for preparation of conjugated polymer dots (Pdots) as ECL materials. The ECL emission of the P-2 Pdots showed obvious red shift from 578 to 598 nm after the fluorene moiety (P-1) was replaced with a stronger electron-donating carbazole moiety. The ECL property could be regulated with intramolecular charge transfer of the D-A moieties, which led to a sharp decline (553 mV) of ECL anodic potential. Furthermore, the ECL intensity significantly increased about 6 times because of the low lowest unoccupied molecular orbital level, which facilitated the electron injection into the conjugated polymer backbone. This work provides an effective strategy for developing AIE-active ECL materials with low potential and high ECL emission intensity via adjusting the D-A electronic structure.

Receptor-Free Detection of Picric Acid: A New Structural Approach for Designing Aggregation-Induced Emission Probes.

A pristine aggregation-induced enhanced emission (AIEE) active monomer 2,5-bis(( E)-4-bromostyryl)-3,4-diphenylthiophene (TPBZ) and its copolymer (PFTPBZ) with 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propandiol) ester have been synthesized via Suzuki coupling polymerization. PFTPBZ that is devoid of any receptor showed AIEE property and demonstrated excellent and selective fluorometric recognition of 2,4,6-trinitrotoluene (TNT) in aggregated state (aqueous medium) and picric acid (PA) in aggregated state and solution state (organic solvent) as well as in vapor phase via PFTPBZ dip-coated Whatman filter paper on a solid-phase platform in 1.86 ng level (naked eye). Limit of detection (LOD) for TNT in 95% water fraction ( fw) was 53.74 × 10-6 M, and at 40% fw, it was 14.26 × 10-7 M. PA detection in tetrahydrofuran solution was possible with a LOD of 28.16 × 10-7 M, 95% fw with LOD of 10.47 × 10-6 M, and in 40% fw with LOD of 47.39 × 10-8 M. As a unique example of structural design, the probe PFTPBZ surprisingly possesses no receptor, yet remarkably high selectivity was achieved via Förster resonance energy transfer (FRET) and photoinduced electron transfer from the copolymer PFTPBZ to PA and TNT. Detection of PA in the presence of various metal analytes and inorganic acids in real water samples (lakes, rivers, and sea water) was also demonstrated using this concept of receptor-free conjugated polymer probe.

Stimuli-responsive supramolecular conjugated polymer with phototunable surface relief grating

A facile method to synthesize azobenzene- and thymine (T)-functionalized conjugated copolymers through Suzuki coupling polymerization and click reactions and used in surface relief gratings displaying long-range-ordered interference patterns.

Synthesis of tetraphenylethylene-based conjugated microporous polymers for detection of nitroaromatic explosive compounds

Conjugated microporous polymers (CMPs) containing tetraphenylethylene (TPE) were synthesized via the Suzuki coupling polymerization. The tetrafunctional TPE moiety in the polymer backbone was linked with the difunctional phenylene group to exhibit a porous structure with high fluorescence in the solid state because of aggregation-induced emissive TPE. The porous polymer with a fluorescent TPE group successfully detected nitroaromatic explosive compounds that exhibited fluorescence quenching, in which the polymer shows high quenching efficiency to picric acid among nitroaromatic explosive compounds. The interaction between the electron-rich TPE group and the electron-deficient nitroaromatic compounds played a decisive role in fluorescence quenching via a photoinduced electron transfer (PET). Compared with a linear polymer containing TPE, the porous, crosslinked polymer showed better sensing performance toward nitroaromatic compounds, presumably because of the more efficient interaction between TPE and nitroaromatic compounds in the pores of TPE-based CMP (TPE-CMP).

Color-tunable AIE-active conjugated polymer nanoparticles as drug carriers for self-indicating cancer therapy via intramolecular FRET mechanism

In this paper, two novel AIE-active conjugated polymers were synthesized by Pd-catalyzed Suzuki coupling polymerization reaction.

Controlled synthesis of ortho, para-alternating linked polyarenes via catalyst-transfer Suzuki coupling polymerization

A novel class of ortho, para-alternating linked polyarenes is synthesized via catalyst-transfer Suzuki coupling polymerization with Pd2(dba)3/t-Bu3P/p-BrC6H4COPh as initiator.

Synthesis and characterization of polyelectrolytes based on benzotriazole backbone

Suzuki coupling and Ni-catalyzed Yamamoto polymerizations were used to prepare conjugated polyelectrolytes based on n-type benzothiadiazole and benzotriazole unit backbone via a one-step synthesis, which started from their monomers with charged pendant ends. PBTBTz-SO3Na synthesized by Suzuki coupling polymerization showed a high M n value of 94 kDa, starting from the bilateral brominated benzotriazole and diboronic ester benzothiadiazole. The PBTBTz-SO3Na revealed aggregation phenomenon at the status of diluted solutions at optical absorption spectroscopy results. Dynamic light scattering (DLS) measurement provided evidence of negative solvatochromic effects of PBTBTz-SO3Na chains in solvents with lower polarity. While, PBTz-PyrBr, PBTz-TMABr, and PBTz-SO3Na which synthesized from Ni-catalyzed Yamamoto polymerizations of bilateral brominated benzotriazole units revealed higher molecular weight with PBTz-PyrBr, M n = 112 kDa; PBTz-TMABr, M n = 157 kDa; and PBTz-SO3Na, M n = 172 kDa, respectively. The ionic pendant groups of monomers have influence on the molecular weight of polymer based on benzotriazole backbone. The optical absorption spectroscopy and DLS measurements presented the negative solvatochromic effects of cationic-CPEs, PBTz-PyrBr, and PBTz-TMABr. Moreover, the UV-vis absorption of PBTz-TMABr displayed higher wavelength of solution (0.0167 mg/mL) than that of film, which was coated from its solution with concentration of 5 mg/mL. These studies displayed insights into the role of pendant ionic functionalities on the molecular weight and optoelectronic properties of the CPEs, which may find application in optoelectronic devices.

Water-Soluble Fluorescent Nanoparticles from Supramolecular Amphiphiles Featuring Heterocomplementary Multiple Hydrogen Bonding

We describe a facile strategy, involving bio-inspired noncovalent molecular recognition, for fabricating water-dispersible luminescent polymer dots without any ionic groups. We first synthesized the thymine-functionalized conjugated polymers PC-T and PTC-T through conventional Suzuki coupling polymerization and copper(I)-catalyzed alkyne/azide cycloaddition (CuAAC). These multiple-hydrogen-bonding materials exhibited distinct luminescent properties in protic and aprotic solvents as well as attractive thermal properties and stabilities; most importantly, they had the ability to pair with complementary base units. Next, we prepared the hydrophilic polymer PEG-A and examined its molecular recognition with PC-T and PTC-T through DNA-like adenine–thymine (A–T) base pairing. We used transmission electron microscopy (TEM) and dynamic light scattering (DLS) to determine the size distributions and dispersibilities of the resulting supramolecular micelles, which appeared as polymeric dots with high signal-to-backgr...

Terpyridyl appended poly(metaphenylene-alt-fluorene) π-conjugated fluorescent polymers: Highly selective and sensitive turn off probes for the detection of Cu2+

Highly soluble and emissive poly(metaphenylene-alt-fluorene) π-conjugated alternative copolymers, with pendant terpyridyl binding sites conjugated to metaphenylene unit, have been synthesized through Pd(0)-catalyzed Suzuki coupling polymerization. For solubilizing in common organic solvents, octyl (P1) or 2-(2-(2-methoxyethoxy)ethoxy)ethyl (P2) side groups have been introduced at 9-position of fluorene. The well-defined copolymers have been characterized by multinuclear NMR and tetradetector GPC with excellent PDI values of 1.28 and 1.14 respectively. The blue emissive π-conjugated polymers show remarkable selectivity and sensitivity towards Cu2+ as turn off fluorescent probes without interference by other competing metal ions, as a result of molecular wire effect. The detailed photophysical and sensing studies have been demonstrated to understand the insight of polymer-metal ion interaction which is responsible for selective fluorescence quenching. Moreover, the polymeric sensors (P1 and P2) are reversible, and can also act as secondary sensors for S2−. The limit of detection (LOD) towards Cu2+ in ppb level with relatively high association constants of 4.1–3.2×105M−1 has prompted us to explore as thin-film polymeric sensor for Cu2+ to develop solid state test kits for practical utility.

Synthesis and property of polyimines containing 2,2,4,4-tetramethyl-1,3-cyclobutadiimine moiety

Although 2,2,4,4-tetramethyl-1,3-cyclobutadione (TMCBDI) has been known for more than 50 years, it has never been used for synthesis of polymer primarily due to its inefficiency in direct polycondensation reaction. We report the first synthesis of high molecular weight polyimines prepared from TMCBDI using Pd-catalyzed Suzuki coupling polymerization. To overcome sluggish condensation polymerization of TMCBDI, it was first converted to diimine monomer containing phenyl bromide on both sides (compound 1) via condensation reaction and polymerized with three different examples aryl diboronate compounds (2a, 2b, 2c). The resulting polyimines (3a, 3b, 3c) were found to exist in a mixture of E and Z isomers in a ratio of 2:1. The number and weight average molecular weights of polyimines were high considering the rigidity of the backbone structure: 20,000 and 44,300 g/mol and 23,100 and 40,500 g/mol for 3a and 3b, respectively. They also showed good thermal stability over 340 °C and a high glass transition temperature over 220 °C. There was no observable photoluminescence from the polyimines in the range of 800 to 300 nm. Apparently, the TMCBDI moiety disrupts electron delocalization in conjugated backbone of polymer chains.