Sonogashira Hagihara Research Articles

Nanostructured Lateral Boryl Substitution Conjugated Donor-Acceptor Oligomers for Visible-Light-Driven Hydrogen Production.

Poor charge separation is the main factor that limits the photocatalytic hydrogen generation efficiency of organic conjugated polymers. In this work, a series of linear donor-acceptor (D-A) type oligomers are synthesized by a palladium-catalyzed Sonogashira-Hagihara coupling of electron-deficient diborane unit and different dihalide substitution sulfur functionalized monomers. Such diborane-based A unit exerts great impact on the resulting oligomers, including distinct semiconductor characters with isolated lowest unoccupied molecular orbital (LUMO) orbits locating in diborane-containing fragment, and elevated LUMO level higher than water reduction potential. Relative to A-A type counterpart, the enhanced dipole polarization effect in D-A oligomers facilitates separation of photogenerated charge carriers, as evidenced by notably prolonged electron lifetime. Owing to π-π stacking of rigid backbone, the oligomers can aggregate into an interesting 2D semicrystalline nanosheet (≈2.74nm), which is rarely reported in linear polymeric photocatalysts prepared by similar carbon-carbon coupling reaction. Despite low surface area (30.3 m2 g-1 ), such ultrathin nanosheet D-A oligomer offers outstanding visible light (λ> 420nm) hydrogen evolution rate of 833 µmol g-1 h-1 , 14 times greater than its A-A analogue (61 µmol g-1 h-1 ). The study highlights the great potential of using boron element to construct D-A type oligomers for efficient photocatalytic hydrogen generation.

Macrocyclic Arenes‐Based Conjugated Macrocycle Polymers for Highly Selective CO2 Capture and Iodine Adsorption

AbstractIncorporating synthetic macrocycles with unique structures and distinct conformations into conjugated macrocycle polymers (CMPs) can endow the resulting materials with great potentials in gas uptake and pollutant adsorption. Here, four CMPs (CMP‐n, n=1–4) capable of reversibly capturing iodine and efficiently separating carbon dioxide are constructed from per‐triflate functionalized leaning tower[6]arene (LT6‐OTf) and [2]biphenyl‐extended pillar[6]arene (BpP6‐OTf) via Pd‐catalyzed Sonogashira–Hagihara cross‐coupling reaction. Intriguingly, owing to the appropriate cavity size of LT6‐OTf and the numerous aromatic rings in the framework, the newly designed CMP‐4 possesses an outstanding I2 affinity with a large uptake capacity of 208 wt % in vapor and a great removal efficiency of 94 % in aqueous solutions. To our surprise, with no capacity to accommodate nitrogen, CMP‐2 constructed from BpP6‐OTf is able to specifically capture carbon dioxide at ambient conditions.

Synthesis of functional conjugated microporous polymer/TiO2 nanocomposites and the mechanism of the photocatalytic degradation of organic pollutants

We successfully synthesize six kinds of functional conjugated microporous polymer (CMP) containing amino, hydroxyl, carboxyl and ester groups by a Sonogashira–Hagihara coupling reaction. These CMPs exhibit type-I nitrogen gas sorption isotherms, and their pore widths are approximately 1.28–1.86 nm with a relatively narrow pore size distribution that is attributed to microporous structures. By blending CMPs with TiO2 under solvothermal conditions, TiO2 is uniformly coated onto the surfaces of the CMPs, and CMP/TiO2 nanocomposites are synthesized successfully. The novel nanocomposites show excellent photocatalytic properties for the degradation of organic pollutants, such as methylene blue, ciprofloxacin and tetracycline, under visible light. The degradation rate of organic pollutants is higher than 96.8%, and after 5 recycling cycles, the degradation efficiency is still more than 93%. The effects of the different functional groups of CMPs on the photocatalytic properties are discussed for the first time. CMP/TiO2 with carboxyl groups show the smallest band gap, highest photocurrent intensity and lowest resistance compared to those of nanocomposites with amino, hydroxyl and ester groups. This result may be caused by the high electronegativity of carboxyl groups, which enhances the charge transfer rate. The photocatalytic mechanism of the CMP/TiO2 nanocomposites is investigated, and the superoxide anion (·O2−) is the main active species in the photocatalytic degradation process.

Bottom-up wet-chemical synthesis of a two-dimensional porous carbon material with high supercapacitance using a cascade coupling/cyclization route

A 2D porous carbon material with excellent electrochemical performance as an electrode in supercapacitors was synthesised using a Sonogashira–Hagihara cross-coupling/Bergman cyclization cascade reaction.

Conjugated microporous polymer foams with excellent thermal insulation performance in a humid environment.

This work reported two monolithic conjugated microporous polymer (CMP) foams synthesized through the Sonogashira–Hagihara cross-coupling reaction without mechanical stirring. The as-synthesized (CMP-ED and CMP-PT) foams exhibited superior hydrophobicity and low apparent density of 58 mg cm−3 and 63 mg cm−3. In addition, CMP-ED displayed a low thermal conductivity of 34.04 mW m−1 K−1, which was comparable with commercial SiO2 aerogels (34.09 mW m−1 K−1) at 50% humidity conditions. When the environment humidity was raised from 50% to 70%, the thermal conductivity of CMP-ED and commercial SiO2 aerogels improved by 0.12% and 7%, respectively. Furthermore, XRD, FTIR, BET and TG were conducted to evaluate the bulk structure and stability of CMP-ED and CMP-PT. The results illustrated the thermal conductivity values were greatly affected by the pore structure of foams. And the strong hydrophobicity and the narrow pore structure were responsible for the good thermal insulation performance under humid conditions. Considering the low density, superhydrophobicity, excellent physicochemical stability and impervious thermal conductivity in a high humidity environment, this CMP-ED presented great potential as an insulating material in a humid environment.

An air-stable organometallic polymer containing titanafluorene moieties obtained by the Sonogashira-Hagihara cross-coupling polycondensation.

The synthesis of a polymer containing alternating titanafluorene and arylene ethynylene moieties is described. The polymerization of a 2,7-dibromo-9-titanafluorene derivative with 1,4-dioctyloxy-2,5-diethynylbenzene is carried out at 70 °C for 48 h in tetrahydrofuran (THF) in the presence of palladium dichloride/4,5-bis(diphenylphosphino)-9,9-dimethylxanthene as a catalyst and diisopropylamine as a base to produce a dark red polymer. The polymer thus obtained is soluble in organic solvents and stable towards both air and moisture. In the UV-vis absorption spectrum of the polymer, the absorption maxima (λmax) are observed at 321 nm and 395 nm, which are bathochromically shifted compared to those of a model compound of the repeating unit, a 2,7-bis(phenylethynyl)titanafluorene derivative (λmax = 309 nm and 364 nm). The optical band gap (Eg) of the polymer is estimated to be 2.8 eV on the basis of the absorption onset, which is narrower than that of the model compound (3.1 eV).

Photonic Switching Porous Organic Polymers toward Reversible Control of Heterogeneous Photocatalysis.

Sonogashira-Hagihara coupling reaction of photoswitchable dithienylethene (AEDTE) with metal-free 5,10,15,20-tetrakis(4-iodophenyl)porphyrin and its metal derivatives (MTIPP, M = H2, Zn(II), Fe(II)) results in three porous organic polymers (POPs) including AEDTE-H2TIPP-POP, AEDTE-ZnTIPP-POP, and AEDTE-FeTIPP-POP. The morphology, components, and structures of newly obtained POPs have been examined by a range of spectroscopic and microscopic techniques including infrared spectroscopy (IR), solid-state UV-vis diffuse reflectance spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The porous structures have been estimated by nitrogen and carbon dioxide sorption isotherms at 77 and 196 K, respectively. The open-AEDTE-H2TIPP-POP with AEDTE in an open form was revealed to be an effective and stable heterogeneous photocatalyst for visible light-driven oxidation of N-methylpyridinium salts possibly because of its relatively large specific surface area. In particular, a proof-of-concept of photoswitchable POP photocatalysts has been established using different light irradiation upon open-AEDTE-H2TIPP-POP to control its heterogeneous photocatalytic behaviors because of the adjustment over the electron transfer process and porous structures through photoisomerization of AEDTE. The present result highlights the bright perspective of photoswitching POPs in the field of materials chemistry and catalysis community.

Acid Functionalized Conjugated Microporous Polymers as a Reusable Catalyst for Biodiesel Production

A series of conjugated microporous polymers (CMPs) based on bromophenol blue (BB) and bromocresol green (BG) have been synthesized via the Sonogashira–Hagihara cross-coupling reaction with surface ...

Highly Sensitive and Selective Fluorescent Probes for Cu(II) Detection Based on Calix[4]arene-Oxacyclophane Architectures.

A new topological design of fluorescent probes for sensing copper ion is disclosed. The calix[4]arene-oxacyclophane (Calix-OCP) receptor, either wired-in-series in arylene-alt-ethynylene conjugated polymers or standing alone as a sole molecular probe, display a remarkable affinity and selectivity for Cu(II). The unique recognition properties of Calix-OCP system toward copper cation stem from its pre-organised cyclic array of O-ligands at the calixarene narrow rim, which is kept in a conformational rigid arrangement by a tethered oxacyclophane sub-unit. The magnitude of the binding constants (Ka = 5.30 − 8.52 × 104 M−1) and the free energy changes for the inclusion complexation (−ΔG = 27.0 − 28.1 kJmol−1), retrieved from fluorimetric titration experiments, revealed a high sensitivity of Calix-OCP architectures for Cu(II) species. Formation of supramolecular inclusion complexes was evidenced from UV-Vis spectroscopy. The new Calix-OCP-conjugated polymers (polymers 4 and 5), synthesized in good yields by Sonogashira–Hagihara methodologies, exhibit high fluorescence quantum yields (ΦF = 0.59 − 0.65). Density functional theory (DFT) calculations were used to support the experimental findings. The fluorescence on–off behaviour of the sensing systems is tentatively explained by a photoinduced electron transfer mechanism.

Sulfur and nitrogen in-situ co-doped hierarchical spherical porous carbon for efficient lithium storage

A new strategy is presented to fabricate sulfur and nitrogen in-situ co-doped hierarchical spherical porous carbon (SNHSPC) and porous carbon nanotube (PCNT) from conjugated microporous polymer using alkynyl monomers and dibromine aromatic compounds as the building blocks through Sonogashira–Hagihara cross-coupling reactions for efficient lithium storage. SEM, XRD, TEM, XPS, nitrogen adsorption/desorption analysis and Raman spectrum were used to determine the structure of SNHSPC and PCNT. SNHSPC is hierarchical spherical porous carbon particles constituted by aggregated porous nano-fibers, which is distinctly different from those of PCNT. SNHSPC feature hierarchical spherical porous carbon, high specific surface area and homogeneous S and N co-doping, which enable a superior lithium storage behavior. The synergy of hierarchically porous structure and dual heteroatoms make SNHSPC afford a high lithium storage capacity, outstanding cycling stability and large rate performance, which are all superior to those of PCNT. The initial reversible capacity of SNHSPC is as high as 776 mA h g−1 at 0.1 A g−1.

Highly efficient solar steam generation of bilayered ultralight aerogels based on N-rich conjugated microporous polymers nanotubes

Solar steam generation is one of the most promising and efficient methods to solve freshwater shortage and to treat the wastewater over the world. However, the preparation of the solar steam generator with simple preparation process, controlled porous structure, high mechanical strength and energy conversion efficiency is still a challenge. Here, we report a bilayered heterocyclic conjugated microporous polymers aerogels based solar receiver by combination of the one-pot Sonogashira–Hagihara reaction of 2-amino-3,5-dibromopyridine and 1,3,5-triethynylbenzene and spraying the polypyrrole on the surface of the aerogels for the solar steam generation. The as-prepared solar steam generator shows nanotubular structure with high porosity (94%), excellent light absorption (ca. 94%), low thermal conductivity (0.031 W m−1 k−1), rapid water transport performance and superior mechanical strength (0.54 MPa under 75% of strain). Under 1 sun illumination, the conjugated microporous polymers aerogels based solar steam generator achieved a high energy conversion efficiency of 80%. This work may provide a simple and novel way to design and fabricate solar receiver with adjustable structure.

Exploiting Hansen solubility parameters to tune porosity and function in conjugated microporous polymers

We expand our recently reported Bristol–Xi'an Jiaotong (BXJ) approach using simple salts to fine tune the porosity of conjugated microporous materials, from Buchwald–Hartwig to Sonogashira–Hagihara, oxidative and Suzuki cross-coupling reactions.

The effects of the crosslinking position and degree of conjugation in perylene tetraanhydride bisimide microporous polymers on fluorescence sensing performance.

In this study, two fluorescence conjugated microporous polymers based on perylene tetraanhydride bisimide (DP4A0 and DP4A2) were prepared via Sonogashira–Hagihara cross-coupling polymerization for the efficient detection of o-nitrophenol (o-NP). They were well characterized via FT-IR, solid state 13C NMR, elemental analysis, and other material characterization techniques. The experiments proved that both CMPs possess high thermal and chemical stability and a porous nature with Brunauer–Emmett–Teller (BET) specific surface areas of 41.3 and 402.1 m2 g−1. Importantly, owing to signal amplification by the conjugated skeleton, DP4A0 and DP4A2 exhibit extremely high sensitivity to o-NP with Ksv values of 1.83 × 104 and 1.69 × 104 L mol−1 and limits of detection of 5.73 × 10−9 and 7.36 × 10−9 mol L−1, respectively. The sensing performance of DP4A0 and DP4A2 was dependent on the position of crosslinking points and crosslinking density. Finally, super amplified quenching was considered the electron transfer mechanism and hydrogen bond interactions were also present.

Synthesis of 1,6-disubstituted pyrene-based conjugated microporous polymers for reversible adsorption and fluorescence sensing of iodine

Four 1,6-disubstituted pyrene-based fluorescent conjugated microporous polymers were synthesized by Sonogashira–Hagihara reaction, trimerization reaction of –CN, and Friedel–Crafts reaction, respectively, which can efficient capture and sense I2.

The influences of the structure of thiophene-based conjugated microporous polymers on the fluorescence sensing properties

Three thiophene-based conjugated microporous polymers (CMPs: TTPTh, DBTh, and TBTh) were prepared by Sonogashira–Hagihara cross-coupling polymerization, and their structures were characterized by FTIR, ss 13C NMR, and elemental analyses.

Dendritic Ligands for Magnetic Suspensions in Liquid Crystals

The synthesis of long‐chain, aliphatic and space filling dendritic ligands containing (pro)mesogenic, aliphatic or nitrile biphenyl moieties for the stabilization of magnetic nanoparticles in liquid crystal hosts is described. A Negishi or Sonogashira cross‐coupling is exploited as a key step in the synthetic sequence. These synthetic procedures enable the synthesis of various ligands which can be easily adapted to different types of liquid crystals [e.g. 4‐pentyl‐4′‐cyanobiphenyl (5CB)]. For instance, a three‐step sequence (i.e. etherfication, Sonogashira–Hagihara cross‐coupling and Steglich‐esterfication) yields a dendritic ligand in 77 % overall yield starting from literature known compounds. The length of the ligand is important to stabilize the magnetic nanoparticles, and, therefore, the length of the ligand may be easily modified by this approach. Indeed, the established synthesis can readily tackle this issue.

Synthesis and crosslinking reaction of a novel polymer containing benzoxazine and phenyleneethynylene moieties in the main chain

ABSTRACTA novel polymer, poly(1) containing benzoxazine and phenyleneethynylene moieties in the main chain with number‐average molecular weights ranging from 1400 to 9800 was obtained quantitatively by the Sonogashira–Hagihara coupling polymerization of the corresponding iodophenyl‐ and ethynylphenyl‐substituted monomer1. Poly(1) was heated at 200 °C under N2for 2 h to obtain the cured polymer, poly(1)′ via the ring‐opening polymerization of the benzoxazine moieties. The structures of the polymer before and after curing were confirmed by1H‐NMR, IR, and UV–vis absorption and reflectance spectroscopies. Poly(1)′ was thermally more stable than monomer1and poly(1). A specimen was prepared from a mixture of poly(1) and phenol‐diaminodiphenylmethane type benzoxazine2by heating at 200 °C for 2 h under N2. The poly(1)/2resin was thermally stable than bisphenol‐A type benzoxazine resin3. Poly(1) exhibited XRD peaks corresponding to thed‐spacings of 1.26–0.98 and 0.40 nm, assignable to the repeating monomer unit and alignment of polymer molecules, respectively. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2019,57, 2581–2589

Synthesis and photoisomerization behavior of polyamide-phenyleneethynylenes bearing azobenzene moieties in the main chain

Novel azobenzene-containing optically active polyamide-phenyleneethynylenes, poly(2–3ap)–poly(2–3bm) were synthesized by the Sonogashira–Hagihara coupling polymerization of azobenzene-containing bis(iodophenylene) monomer 2 and m-, p-diethynylbenzene derivatives 3ap–3bm. Polymers with number-average molecular weights of 1500–107,800 were obtained in 52%-quantitative yields. The azobenzene moiety of 2 showed reversible light-induced trans–cis isomerization, while the polymers showed irreversible isomerization depending on the composition of mixed solvents.

Adamantane-Based Micro- and Ultra-Microporous Frameworks for Efficient Small Gas and Toxic Organic Vapor Adsorption.

Microporous organic polymers and related porous materials have been applied in a wide range of practical applications such as adsorption, catalysis, adsorption, and sensing fields. However, some limitations, like wide pore size distribution, may limit their further applications, especially for adsorption. Here, micro- and ultra-microporous frameworks (HBPBA-D and TBBPA-D) were designed and synthesized via Sonogashira–Hagihara coupling of six/eight-arm bromophenyl adamantane-based “knots” and alkynes-type “rod” monomers. The BET surface area and pore size distribution of these frameworks were in the region of 395–488 m2 g−1, 0.9–1.1 and 0.42 nm, respectively. The as-made prepared frameworks also showed good chemical ability and high thermal stability up to 350 °C, and at 800 °C only 30% mass loss was observed. Their adsorption capacities for small gas molecules such as CO2 and CH4 was 8.9–9.0 wt % and 1.43–1.63 wt % at 273 K/1 bar, and for the toxic organic vapors n-hexane and benzene, 104–172 mg g−1 and 144–272 mg g−1 at 298 K/0.8 bar, respectively. These are comparable to many porous polymers with higher BET specific surface areas or after functionalization. These properties make the resulting frameworks efficient absorbent alternatives for small gas or toxic vapor capture, especially in harsh environments.

Conjugated helical polymers: End-group control and coupling reactions

Telechelic helical poly(phenyleneethynylene)s 2 and 3 bearing end iodo and ethynyl groups were synthesized by the Sonogashira–Hagihara coupling reaction of prepolymer 1 with N-α-tert-butoxycarbonyl-3,5-diiodo-4-hydroxy-d-phenylglycine hexylamide (4) and p-diethynylbenzene (5), respectively. Polymer 2 was treated by Sonogashira–Hagihara coupling reaction with 1,6-diethynylpyrene (a) and 4,4-diethynylbiphenyl (b) to obtain the corresponding polymers 2a and 2b. Polymer 2 was also subjected to the Mizoroki–Heck coupling reaction with diphenyl(p-vinylphenyl)phosphine (e) to obtain the corresponding polymer 2e, and the incorporation of the phosphine moieties was confirmed by 31P NMR spectroscopy. In a similar fashion, polymer 3 was polymerized with 1,4-dibromonaphthalene (c) and 9,10-dibromoanthracene (d), but no concrete evidence for the formation of polymers 3c and 3d was observed. Circular dichroism (CD) spectroscopic analysis revealed that all the polymers adopted folded helical conformations with predominantly one-handed screw sense in CHCl3. The polymers exhibited photoluminescence (PL) depending on the incorporated functional groups.