Phenylacetylene Groups Research Articles

Melting Effect on the Thermal Hazard of Anthraquinone Dyes Waste: Based on the Thermal Decomposition Characteristics and Quantum Mechanics

Thermal decomposition of typical hazardous anthraquinone dye waste was tested through differential scanning calorimetry, and the interaction of the components was analyzed by the model-free method. The test results show that melting makes the solid-phase decomposition of 1,5-dinitroanthraquinone decrease as the activation energy is reduced by about 142.08 kJ/mol. The activation energy of the third step of decomposition of the mixture should be lowered. The spatial configuration of each substance was described based on quantum mechanics tools. The calculation results of the Laplace bond show that the middle ring bond is broken with detachment of the nitro group. The polynitro substance needs to remove the −CO group and form a stable phenylacetylene group that can react with anthraquinone. The reactivity rating number under extreme fire conditions was simulated by the kinetic equation. It shows that the mixture without anthraquinone has a higher heat production rate and overall heat effects under high temperatures. The melting effect of anthraquinone will make the decomposition of the mixture become more stable except under elevated temperatures and pressures.

Investigation of poly(phenylacetylene) derivatives for carbon precursor with high carbon yield and good solubility

This paper investigates a family of poly(phenylacetylene) derivatives with a p-electrons conjugated polymer backbone and side groups containing only sp2 and sp carbons. The objective is to identify the suitable carbon precursor that is processible and can be transformed to carbonaceous material with high carbon yield by a simple (one-step) thermal transformation process (without any external reagent). Poly(phenylacetylene) with para-substituted acetylene group poly(PA-A) shows an exceptionally high C-yield (~90%) in one-step heating from ambient temperature to 1000 °C under N2 atmosphere. Unfortunately, this poly(PA-A) polymer is quite sensitive to heat and light with very limited solubility. On the other hand, poly(phenylacetylene) with para-substituted phenylacetylene group, i.e. poly(PA-PA), offers a relatively high C-yield (~80%) and also good solubility in common organic solvents, such as toluene and tetrahydrofuran (THF). Several uniform dark-red poly(PA-PA) fibers with smooth surface and fiber diameter in the range of 3–6 μm were prepared from 30 wt% poly(PA-PA)/THF solution using electrospinning technique. The resulting precursor fibers were converted to the corresponding carbon structure in a one-step thermal heating process under N2 atmosphere. Both X-ray and Raman spectra show the polymorphous carbon morphology with the graphene crystalline domains.

Synergy of electrochemical grafting and crosslinkable crystalline sizing agent to enhance the interfacial strength of carbon fiber/PEEK composites

Carbon fiber/PEEK composites have gained significant attention in the field of continuous carbon fiber reinforced polymers (CFRPs). However, it remains challenging to improve the weak interfacial strength between carbon fiber (CF) and PEEK matrix. In this paper, strong interactions at the interface of sizing agent and carbon fiber were effectively achieved by introducing chemical bonds. Specifically, a soluble PEEK sizing agent where aniline served as pendant group and phenylacetylene served as blocking agent was synthesized. In the meantime, the phenylacetylene group was grafted on the carbon fiber surface through electroreduction. Then, the soluble sizing agent was used to size the electrochemical treated carbon fiber. After the heat treatment, chemical bonds were established by the crosslinking reaction of phenylacetylene groups existed in both the surface of carbon fiber and sizing agent. Meanwhile, the crystalline structure in the sizing layer was remained, which could improve the toughness of the interphase. As a result, the interfacial shear strength (IFSS) increased by 137.5% from 43.4 MPa of the untreated carbon fiber (U-CF) to 103.1 MPa of the reductive electrografted and coated carbon fiber (E-C-CF). The interlaminar shear strength (ILSS) also increased by 66.8% from 58.4 MPa of untreated CF/PEEK composites (U-CF/PEEK) to 97.4 MPa of reductive electrografted and coated CF/PEEK composites (E-C-CF/PEEK). The outstanding performances could be attributed to better compatibility of sizing agent and most importantly, the existence of chemical bonds between the carbon fiber and sizing agent.

Controlled Synthesis of Poly(vinyl ether)-Grafted Poly(phenylacetylene)s by a Combination of Living Coordination Polymerization and Living Cationic Polymerization.

We newly designed a functionalized monomer (PhAVE-AcOH) containing a phenylacetylene (PhA) group and a 1-(acetoxy)ethoxy group, the latter of which is expected to act as an initiator moiety in combination with Lewis acid-based activators under living cationic polymerization conditions. A polyPhA-based multifunctional initiator poly(PhAVE-AcOH) with a narrow molecular weight distribution (Mw/Mn = 1.02) was synthesized by Rh complex-mediated living coordination polymerization of PhAVE-AcOH. Then, living cationic graft polymerization of isobutyl vinyl ether (IBVE) was performed employing the pendant 1-(acetoxy) ethoxy initiating moiety of poly(PhAVE-AcOH) to form polyIBVE-grafted polyPhA(polyPhA-g-polyIBVE), where both the main chain and side chains possessed well-controlled structures (Mw/Mn = 1.05–1.10). We found that UV–vis absorption spectra of polyPhA-g-polyIBVE were progressively redshifted with increasing molecular weights of the graft chain.

New quinazolinone derivatives and its nonlinear optical properties

A series of quinazolinone-based materials was synthesized and fully characterized. Firstly, the third-order nonlinear optical properties of the quinazolinone derivatives in CH2Cl2 were investigated by using Z-scan measurement. Secondly, the photophysical properties of the compounds were determined with aid of experimental and theoretical calculation methods. The results showed that the introduction of phenylacetylene groups on the planar structure of parent ring of 1a reduced the π-π intermolecular stacking of parent ring compound, and the formation of push-pull structure by connecting phenylacetylene groups to quinazolinone backbone decreased energy gap of entire molecule. A good NLO response was obtained, that the second-order NLO susceptibilities (γ) of 2b were 6.225 × 10−31 esu, which is more than 7 times higher than that of no-modified 1a. Our results indicate that the quinazolinone derivatives were promising candidate materials for future nonlinear optical applications.

Novel crosslinkable epoxy resins containing phenylacetylene and azobenzene groups: From thermal crosslinking to flame retardance

Several kinds of novel flame-retardant-free and thermo-crosslinkable epoxy resins (EPs) containing azobenzene or/and phenylacetylene groups have been synthesized and characterized, and the flame retardant properties as a result of thermal crosslinking during combustion were investigated in detail. Crosslinking behaviors were tested by simultaneous thermogravimetry–differential scanning calorimetry (TGA–DSC). Thermal stabilities were investigated by thermogravimetric analysis (TGA). Flame retardance of the resulting EPs was evaluated through LOI tests, and combustion behaviors were studied via cone calorimetry and micro-combustion calorimetry (MCC), which further confirmed that flame retardance of these EPs was significantly improved, despite the absence of conventional flame retardant. Py–GC/MS analysis was used to investigate the degradation mechanism of these epoxy resins, and the results confirmed that the flame-retardant activity of epoxy resins mainly took effect in the condensed phase. The chemical constitution of the char layers were investigated by XPS and Raman spectrum. The co-crosslinking behavior between azobenzene and phenylacetylene groups was predicted and confirmed, which led to the most compact char layer, therefore resulted in the best flame retardance of these EPs.

Solvent effect on the excited state of stilbene dendrimers bearing phenylacetylene groups

We studied the characteristics of emissive state of the first (p-G1) and second (p-G2) generation of phenylacetylene dendrimers bearing stilbene as a core by using time-resolved fluorescence spectroscopy in cyclohexane (c-Hex) and N, N-dimethylformide (DMF), which are nonpolar and polar solvents, respectively. Time-dependent red-shift of emission spectra p-G2 both in c-Hex and DMF was observed in comparison with p-G1. Besides, the time constant of red-shift of spectra was found to be larger in DMF than in c-Hex. This indicates that the emissive state of p-G2 has a polar character in DMF as a result of charge delocalization from core to peripheral dendrons followed by stabilization of emissive state.

Synthesis of brush-shaped polymers consisting of a poly(phenylacetylene) backbone and pendant poly(vinyl ether)s via selective reaction of 2-Vinyloxyethyl 4-Ethynylbenzoate

We have newly designed an original bifunctional monomer (PAVE) containing both a phenylacetylene (PA) group and a vinyl ether (VE) group, which is expected to be a key material for the synthesis of brush-shaped polymers consisting of a poly(phenylacetylene) (polyPA) main chain and polyVE side chains. Actually, we have demonstrated the selective chemical transformation of the VE moiety of PAVE to an initiator site for the living cationic polymerization of isobutyl vinyl ether (IBVE), and then succeeded in the controlled synthesis of a novel PA-end-capped polyIBVE macromonomer. Moreover, using this macromonomer, the first synthesis of a brush-shaped polyPA bearing polyVE side chains was achieved via Rh complex-mediated homopolymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 2800–2805

Synthesise of (4-Ethynyl-Phenyl)-(4-trifluoromethyl-phenyl)-Diazene, a Novel Intermediate of Azobenzene Liquid Crystal with High Birefrigence

In order to obtain an important azobenzene liquid crystal intermediate with phenylacetylene group, Sonogashira coupling reaction was used to preparation the compound. In this paper, the intermediate was synthesized by (4-Iodo-phenyl)-(4-trifluoromethyl-phenyl)-diazene and trimethyl silyl acetylene (TMSA) as raw materials, and then the trimethyl silyl group was removaled under the action of K2CO3. During the synthesis, the optimum reaction conditions were obtained, that the mol ratio of (4-Iodo-phenyl)-(4-trifluoromethyl-phenyl)-diazene and trimethyl silyl acetylene was 1:2, the reaction temperature was 80 oC. Fourier transform infrared spectroscopy (FT-IR) was used to measure the molecular structure of the target compound.

Dimerization Reaction of Regioisomeric Bis(phenylethynyl)benzene Radical Anions during Pulse Radiolysis

AbstractDimerization of a series of regioisomeric 1,4‐, 1,3‐, and 1,2‐bis(phenylethynyl)benzene radical anions (bPEBs.−) substituted by various electron‐donor and/or electron‐acceptor groups was studied during the pulse radiolysis in N,N‐dimethylformamide (DMF). The transient absorption of bPEB.− decayed with the formation of new bands attributed to the dimer radical anion of bPEB.− and bPEB (bPEB2.−). From the dependence of decay and formation rates on the concentration of bPEB, the bimolecular rate constants of kb=(1.2±0.1)×107 to (3.2±0.2)×108 M−1 s−1 were estimated. It is suggested that bPEB.− dimerizes with bPEB through the formation of a CC bond between two sp carbon atoms, to give σ‐type dimer radical anion (σ‐(bPEB)2.−) with a diene‐type structure. The kb values of bPEB.− with bPEB changed with the substitution pattern of the phenylacetylene group on the central benzene ring and the various kinds of donor and/or acceptor group.

Novel Cytochrome P450 Bioactivation of a Terminal Phenyl Acetylene Group: Formation of a One-Carbon Loss Benzaldehyde and Other Oxidative Products in the Presence of N-Acetyl Cysteine or Glutathione

Compounds 1 (N1-(3-ethynylphenyl)-6-methyl-N5-(3-(6-(methylamino)pyrimidin-4-yl)pyridin-2-yl) isoquinoline-1,5-diamine) and 2 (N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)quinazolin-4-amine; Erlotinib/Tarceva) are kinase inhibitors that contain a terminal phenyl acetylene moiety. When incubated in the presence of P450 and NADPH, the anticipated phenyl acetic acid metabolite was formed. When 10 mM of N-acetyl-l-cysteine was added to the incubation mixtures, the phenyl acetic acid product was reduced and at 25 mM or higher concentration of NAC, formation of the phenyl acetic acid was abolished. Instead, the phenyl acetylene moiety lost a carbon and formed a benzaldehyde product. Other oxidation products incorporating one or more equivalents of NAC were also observed. The identities of the metabolites were characterized by MS and NMR. Addition of deferoxamine or ascorbic acid diminished the formation of the NAC influenced products. Similar products were also observed when 1 or 2 were incubated in P450 reactions supplemented with GSH, in Fenton reactions supplemented with NAC or GSH, and in peroxidase reactions supplemented with NAC. We propose the thiols act as a pro-oxidant readily undergoing a one-electron oxidation to form thiyl radicals which in turn initiates the formation of other peroxy radicals that drive the reaction to the observed products. These in vitro findings suggest that one-electron oxidation of thiols may promote the cooxidation of xenobiotic substrates.

Emission from Regioisomeric Bis(phenylethynyl)benzenes during Pulse Radiolysis

Emission from charge recombination between radical cations and anions of a series of regioisomeric 1,4-, 1,3-, and 1,2-bis(phenylethynyl)benzenes (bPEBs) substituted by various electron donor and/or acceptor groups was measured during pulse radiolysis in benzene (Bz). The formation of bPEB in the excited singlet state ((1)bPEB*) can be attributed to the charge recombination between bPEB(*+) and bPEB(*-), which are initially generated from the radiolytic reaction. This mechanism is reasonably explained by the relationship between the annihilation enthalpy change (-DeltaH(o)) for the charge recombination of bPEB(*+) and bPEB(*-) and excitation energy of (1)bPEB*. Since the degree of the pi-conjugation in the S(1) state and HOMO-LUMO levels of bPEB change with the substitution pattern of phenylacetylene groups on the central benzene ring and the various kinds of donor and/or acceptor group, the fine-tuning of the emission color and intensity of bPEB can be easily carried out during pulse radiolysis in Bz. For donor-acceptor-substituted bPEB, it was found that the difference in the charge transfer conjugated pathways between donor and acceptor substituents (linear-, cross-, and "bent"-conjugated pathways) strongly influenced the HOMO-LUMO energy gap.

Stability and flexibility of self-assembled monolayers of thiols consisting of a horizontal largeπ-system and a vertical spacer

Self-assembled monolayers (SAMs) of (4-mercaptophenyl) (10-nitro-9-anthryl) acetylene(MPNAA) on Au(111) are studied with scanning tunneling microscopy (STM). Throughcareful analysis of the bias-dependent sub-molecular features observed in thehigh-resolution STM images, important structural details of the MPNAA SAM aredisclosed, in addition to its structural character common for the anthracene-based thiolSAMs studied in a recent paper (Dou et al 2006 Langmuir 22 3049). With theseexperimental results, a new model is proposed for the SAM structure to explain,particularly, the molecule–substrate, molecule–molecule and intramolecular interactions, aswell as their competitions and compromises in the formation of the SAM structure.Flexibilities and application potentials of the SAMs of thiols based on a longπ-system (like that of anthracene or even pentacene) arranged horizontally and a verticalspacer (like the phenyl–acetylene group) are also discussed.

Synthesis and Antiviral and Cytostatic Evaluations of the New C-5 Substituted Pyrimidine and Furo[2,3-d]pyrimidine 4‘,5‘-Didehydro-l-ascorbic Acid Derivatives

The novel C-5 alkynyl substituted pyrimidine (1-11) and furo[2,3-d]pyrimidine derivatives (12-22) of l-ascorbic acid were synthesized by coupling of 5-iodouracil-4',5'-didehydro-5',6'-dideoxy-l-ascorbic acid with terminal alkynes by using Sonogashira cross-coupling reaction conditions. The new compounds were evaluated for their cytostatic and antiviral activities. Among all evaluated compounds, the octynyl-substituted uracil derivative of l-ascorbic acid (3) exhibited the most pronounced cytostatic activities against all examined tumor cell lines (IC50 = 2-12 microM). Pyrimidine derivatives of l-ascorbic acid containing p-substituted phenylacetylene groups (8-11) displayed also a rather pronounced (IC50 = 3-37 microM) inhibitory effect toward all tumor cell lines. From the bicyclic series of compounds, 6-butylfuro[2,3-d]pyrimidine derivative (12) and 6-p-bromophenylfuro[2,3-d]pyrimidine derivative (19) showed the highest cytostatic activity (IC50 = 4.5-20 microM), particularly against malignant leukemia (L1210) and T-lymphocyte (Molt4/C8 and CEM) cells. Compounds 3 and 9 showed specific albeit moderate activity against cytomegalovirus (CMV, Davis strain, EC50 = 1.8 and 3.8 microM, respectively, for compounds 3 and 9) at a approximately 5-fold lower concentration than that required to show cytotoxicity.

The relaxation dynamics of the excited state of stilbene dendrimers substituted with phenylacetylene groups

Energy migration and emitting processes of a series of dendrimers linked by a phenylacetylene group bearing stilbene as a core were investigated by steady state and time-resolved fluorescence spectroscopy. In higher generation, we confirmed efficient energy migration from peripheral moiety to a core followed by emission with high quantum yield. The kinetics of emitting state was also examined by lifetime measurement and revealed generation dependence of fluorescence decay constants. In the case of higher generation, peripheral moieties might be involved in relaxation process in the excited state in contrast to negligible interaction to the core in the ground state.

Development of the Nematic Liquid Crystal Compounds Derived from Phenyl Acetylene Group with Large Birefringence

Novel liquid crystal compounds with extraordinary large birefringence have been studided from the viewpoint of optical anisotropy. A large birefrinence was obtained in the compounds compared with that in 5CB, while the orientational order parameters determined by FT-IR measurement are almost the same. From the calculated results of molecular polarizability, it is concluded that the large optical anisotropy is mainly caused by the electric anisotropy.

Sulfones as Radical Progenitors: An Unprecedented Example of Homolytic Sulfone Cleavage Facilitated by o-Stannyl Substitution of Aryl Sulfones(1).

Allylic aryl sulfones bearing an o-allyldialkylstannyl moiety (1b), when converted to stannyl radical 1a, suffer homolytic cleavage via intramolecular attack of the stannyl radical on the sulfone. Allyl radicals generated in this manner can be utilized for further intramolecular radical cyclizations; thus the overall transformation can be viewed as an alkylative desulfonylation reaction. Previously unknown sulfonyl stannane polymer 5 is generated as a byproduct. The o-dibutylstannyl radical derived from nonallylic aryl sulfone 15 does not suffer homolysis but instead forms 9-membered macrocycle 19 via an intramolecular reaction with the phenylacetylene group.

Magnetic shielding of acetylenic protons in substituted phenylacetylenes

Abstract The magnetic shieldings of acetylenic protons in ortho, meta and para -substituted phenylacetylenes have been determined at infinite dilution in carbon tetrachloride at 23°. A marked dependence of the shielding on the nature and position of the ring substituent is noted. Strongly electron-donating substituents lead to an increase in shielding of the acetylenic proton while electron-withdrawing substituents decrease the shielding. Ortho -substitution decreases the shielding of the acetylenic proton in all cases. The shieldings for para -substituted phenylacetylenes can be interpreted in terms of inductive and resonance interactions of the substituents with the phenylacetylene group. Shieldings for ortho - and meta -substituted compounds are susceptible to magnetic anisotropy and electric field effects and a simple interpretation of the τ values for these compounds is not feasible.