Alkyl Phenyl Groups Research Articles

Enhanced Photovoltaic Performances via Chlorine Substitution on Alkylphenyl Side Chains of a Conjugated Polymer

Owing to the enhanced intermolecular interaction, aromatically chlorinated polymers have been energetic to the molecular design and innovation of π-conjugated polymers for efficient organic solar cells (OSCs). Herein, two structurally similar copolymer donors (Z1 and Z2) based on benzodithiophene (BDT) on alkylbenzene conjugated side chains without and with chlorine atoms were designed and synthesized. Two copolymers possessed similar absorption spectra ranging from 380 to 620 nm and approximated optical band gap (Egopt). Compared with the nonchlorinated polymer Z1, polymer Z2 substituted by chlorine in the meta-position of the alkylphenyl group endowed it an enhanced π–π stacking and favorable morphology, which brought the OSCs the significantly enhanced photocurrent and fill factor as well as hole/electron mobility. When the nonchlorinated copolymer Z1 showed a power conversion efficiency (PCE) of 12.03%, the chlorinated copolymer Z2 obtained a higher PCE of 15.11%. The results provide more insight into the role of the chlorinated alkylphenyl side chains in designing new conjugated polymers to promote the performance of OSCs.

Macromolecular helicity induction and static helicity memory of poly(biphenylylacetylene)s bearing aromatic pendant groups and their use as chiral stationary phases for high-performance liquid chromatography.

Two novel poly(biphenylylacetylene)s (PBPAs) bearing achiral alkylphenyl groups at the 4'-position of the biphenyl pendant through ester linkers with different sequences were synthesized by the rhodium-catalyzed polymerization of the corresponding monomers. The influence of the alkylphenyl pendants and the ester sequences on the macromolecular helicity induction and subsequent static helicity memory was investigated. In addition, the chiral recognition ability as chiral stationary phases for high-performance liquid chromatography of the helicity-memorized PBPAs was also examined. Both polymers formed almost perfect right- and left-handed helical conformations through noncovalent chiral interactions with enantiomeric alcohols, and their induced macromolecular helicities were completely retained ("memorized") after removal of the helix inducer. A PBPA bearing a 4-n-butylphenoxycarbonyl pendant group with a static helicity memory showed a remarkably high chiral recognition ability toward a wide variety of chiral aromatics, including simple point chiral compounds, axially chiral biaryls, a chiral spiro compound, helicenes, and planar chiral cyclophanes, particularly under the reversed-phase conditions.

Overcoming the trade-off between Voc and Jsc: Asymmetric chloro-substituted two-dimensional benzo[1,2-b:4,5-b′]dithiophene-based polymer solar cells

To achieve the high PCE and simultaneously overcome the trade-off between open circuit voltage (VOC) and short-circuit current density (JSC), the reasonable design of the donor material is still a great challenge in non-fullerene polymer solar cells (PSCs). Herein, a pair of asymmetric 2D BDT-based wide band gap polymers, named PBPTBz-1Cl and PBPTBz-2Cl, respectively, were designed and synthesized through simultaneously introducing a chloro-substituted thiophene and another alkoxylphenyl groups as side chains onto the same BDT unit. As expected, the polymers PBPTBz-1Cl and PBPTBz-2Cl exhibit the deeper HOMO levels of −5.32 and −5.41 eV, respectively, compared with the HOMO value of −5.27 eV for chlorine-free substituted polymer PBPTBz-0Cl. Therefore, the PBPTBz-2Cl:IT-M based PSCs exhibited a higher Voc of 0.99 V, with an enhanced Jsc of 14.92 mA cm−2 and PCE of 7.18%. The Voc, Jsc and PCE were simultaneously enhanced from PBPTBz-0Cl:IT-M to PBPTBz-1Cl:IT-M, then to PBPTBz-2Cl:IT-M based PSCs successively. These results demonstrate that the challenge of the trade-off between Voc and Jsc could be overcome through the asymmetric strategy of the chloro-substituted thiophene and alkylphenyl groups as different side chains onto the same BDT unit. Hence, considering the low cost of starting materials and convenient introduction of chlorine atoms, the asymmetric chlorination of the side chain of BDT unit would be the great potential for achieving the high-performance PSCs.

N-substituted dithienopyrroles as electrochemically active monomers: Synthesis, electropolymerization and spectroelectrochemistry of the polymerization products

Two new electropolymerizable monomers were synthesized, namely dithieno[3,2-b:2′,3′-d]pyrrole N-functionalized with 4-(2-heptylthiazol-4-yl)phenyl (DTP1) and 4-(5-octylthiophen-2-yl)phenyl (DTP2) groups. Both monomers readily electropolymerize to yield the corresponding polyDTP1 and polyDTP2. Electrochemically determined ionization potential (IP) of both polymers (about 4.75 eV) are higher than IPs of poly(dithieno[3,2-b:2′,3′-d]pyrrole) N-substituted with alkyl or alkylphenyl groups. This finding, corroborated by DFT calculations, suggests that electron accepting nature of (thiazol-4-yl)phenyl and (thiophen-2-yl)phenyl substituents lowers the π-electron density in the dithienopyrrole moiety making the polymers oxidation more difficult. Optical band gaps of polyDTP1 (Eg opt = 1.76 eV) and polyDTP2 (Eg opt = 1.78 eV) are lower than the gaps of poly(dithieno[3,2-b:2′,3′-d]pyrrole) N-substituted with alkyl or alkylphenyl groups. This combined with higher IP value yield higher electron affinity (ǀEAǀ) value. Thus, the obtained new polymers are more difficult to oxidize but easier to reduce as compared to poly(dithieno[3,2-b:2′,3′-d]pyrrole)s studied to date. Again, these findings are in a very good agreement with DFT calculations. As evidenced by UV–vis–NIR spectroelectrochemistry, both polymers undergo classical (for conjugated polymers) oxidation, involving the formation of polarons in the first step and bipolarons in the second one. An interesting feature of the oxidation of polyDTP2 is the highly delocalized nature of bipolarons, indicative of the metallic state (featureless absorption tails extending towards NIR part of the spectrum). In order to elucidate the exact nature of the electrochemical oxidation process detailed Raman spectroelectrochemical investigations of polyDTP2 were carried out supported by the vibrational model calculations using two methods: DFT and General Valence Force Field (GVFF). This combined experimental and theoretical study leads to a conclusion that radical cations (polarons) formed at the first stage of oxidation are formed in the pyrrole ring whereas dications formed in the second stage show classical bipolaron configuration with positive charges located on the thiophene rings.

Design, synthesis, and evaluation of novel N-1 fluoroquinolone derivatives: Probing for binding contact with the active site tyrosine of gyrase

Structural studies of topoisomerase-fluoroquinolone-DNA ternary complexes revealed a cavity between the quinolone N-1 position and the active site tyrosine. Fluoroquinolone derivatives having positively charged or aromatic moieties extended from the N-1 position were designed to probe for binding contacts with the phosphotyrosine residue in ternary complex. While alkylamine, alkylphthalimide, and alkylphenyl groups introduced at the N-1 position afforded derivatives that maintained modest inhibition of the supercoiling activity of DNA gyrase, none retained ability to poison DNA gyrase. Thus, the addition of a large and/or long moiety at the N-1 position disrupts ternary complex formation, and retained ability to inhibit supercoiling is likely through interference with the strand breakage reaction. Two derivatives were found to possess inhibitory effects on the decatenation activity of human topoisomerase II.

Synthesis and evaluation of pyridinium-hydrazone derivatives as potential antitumoral agents.

The hydrazones of 4-hydrazinylpyridinium bearing alkylphenyl groups on pyridinium nitrogen were synthesized and evaluated for their cytotoxic activity against MCF-7, PC3, U2OS, and HEK293 cell lines by Wst1 cell proliferation assay. Cytotoxic activity results indicated that d derivatives having butylene chain; 4 and 5 series having naphthalene and anthracene ring systems showed high cytotoxic activity (IC50 =3.27-8.54μm) on cancer cells. 3d (4-(2-(4-hydroxybenzylidene)hydrazinyl)-1-(4-phenylbutyl)pyridinium bromide) was the most cytotoxic compound with IC50 value of 3.27μm against MCF-7. The most active derivatives (1d, 2d, 3d, 4, and 5 series) were selected to investigate for the effects on autophagy by analyzing the expression of autophagy marker proteins. The conversion of LC3-I to its lipidated form LC3-II is essential for autophagy and related to autophagosomes. According to our results, all tested compounds except for 3d induced lipidated form LC3-II accumulation. Then, the effects of the compounds on p62 protein level were also analyzed by the immunoblotting as the autophagy inhibition results in accumulation of p62. Further molecular mechanistic studies including morphological analysis and live-death assays indicated that all tested compounds (1d, 2d, 3d, 4, and 5 series) are potent antitumoral molecules and all except for 3d have potential to inhibit autophagic flux.

Synthesis, Biological Evaluation and Molecular Docking Study of Hydrazone-Containing Pyridinium Salts as Cholinesterase Inhibitors.

A series of pyridinium salts bearing alkylphenyl groups at 1 position and hydrazone structure at 4 position of the pyridinium ring were synthesized and evaluated for the inhibition of both acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. The cholinesterase (ChE) inhibitory activity studies were carried out by using the Ellman's colorimetric method. All compounds displayed considerable AChE and BuChE inhibitory activity and some of the compounds manifested remarkable anti-AChE activity compared to the reference compound, galantamine. Among the title compounds, the series including benzofuran aromatic ring exhibited the best inhibitory activity both on AChE and BuChE enzymes. Compound 3b, 4-[2-(1-(benzofuran-2-yl)ethylidene)hydrazinyl]-1-(3-phenylpropyl)pyridinium bromide, was the most active compound with IC50 value of 0.23 (0.24) µM against enantiomeric excess (ee)AChE (human (h)AChE) while compound 3a, 4-[2-(1-(benzofuran-2-yl)ethylidene)hydrazinyl]-1-phenethylpyridinium bromide, was the most active compound with IC50 value of 0.95 µM against BuChE. Moreover, 3a and b exhibited higher activity than the reference compound galantamine (eeAChE (hAChE) IC50 0.43 (0.52) µM; BuChE IC50 14.92 µM). Molecular docking studies were carried out on 3b having highest inhibitory activity against AChE.

Highly transmissive blue electrochromic polymers based on thieno[3,2-b]thiophene

Polymers based on a thieno[3,2-b]thiophene core modulated by alkylphenyl groups show high optical contrast and deep blue to highly transmissive electrochromic performances.

Tribological studies of highly hydrolytically stable N-containing long chain alkyl phenylborate esters in mineral oil

The tribological properties and hydrolytic stabilities of two novel N-containing long chain alkyl phenylborate esters, 2-(4-dodecylphenyl)-6-octadecyl-1,3,6,2-dioxazaborate (DBDB), and bis(2-(2-((E)-heptadec-8-enyl)-4,5-dihydro-1H-imidazol-1-yl) ethyl)-4-dodecylphenylborate (OMDB), as lubricating additives in mineral oil (HVI WH150) were evaluated. The results confirm that the two additives possess good anti-wear property and excellent hydrolytic stability, which demonstrates that the new approach by introducing long chain alkyl phenyl group is an effective way to improve the hydrolytic stability of borate esters. X-ray absorption near edge structure (XANES) spectroscopy was adopted to analyze the thermo-oxidative films and tribofilms generated from the synthesized additives in base oil to further understand their tribological behaviors on the metal surfaces. The XANES spectra reveal that the thermal films are mainly composed of trigonal coordination boron, while the tribofilms consist of trigonal and tetrahedral coordination borons in comparison with the model compounds, which suggests that the additive can generate the tetrahedral boron species or the trigonal boron species partially undergoing transformation to produce tetrahedral boron species during the vigorous condition of rubbing process.

Ring closing and opening reactions leading to aza-polycyclic aromatic compounds

A series of functionalized aza-polycyclic aromatic compounds were prepared by a superacid-promoted ring closing and opening reaction cascade. A reaction mechanism is proposed, which involves reactive dicationic intermediates. A key step in the conversions involves ipso protonation of an aryl group and elimination of an alkyl phenyl group.

Synthesis and gas permeability of ester substituted poly( p-phenylene)s

Polymerizations of various ester substituted 2,5-dichlorobenzoates [substituent: linear alkyl groups ( 1a– f), branched alkyl groups ( 1g– l), cyclohexyl groups ( 1m– o), phenyl groups ( 1p– r), and oxyethylene units ( 1s– v)] were investigated with Ni-catalyzed/Zn-mediated system in 1-methyl-2-pyrrolidone (NMP) at 80 °C. Most of monomers bearing linear and branched alkyl groups successfully polymerized to give relatively high-molecular-weight polymers ( M n = 10,000–20,800). However, the molecular weight of the polymer having eicocyl groups was low because of steric hindrance of long alkyl chain. The polymerizations of cyclohexyl 2,5-dichlorobenzoate and phenyl 2,5-dichlorobenzoate produced low-molecular-weight polymers, while the polymerizations of monomers with alkyl cyclohexyl and alkyl phenyl groups proceeded to afford polymers with relatively high-molecular-weights. The polymers possessing oxyethylene units were obtained, but the molecular weights were low when the oxyethylene chains were long. The gas permeability of membranes of poly( p-phenylene)s with alkyl chains increased as increasing the length of alkyl chain. The membranes of poly( p-phenylene)s with phenyl groups and oxyethylene units exhibited high densities and relatively low gas permeability. However, the CO 2/N 2 separation factor of membrane of poly( p-phenylene) having oxyethylene units was as large as 73.6.

The effect of polyethylene glycols on zinc dissolution at 50 °C in 0.5 M H 2SO 4 containing Co, Sb and Ge

The effect of the structure of polyethylene glycols [i.e. the presence of alkylphenyl group (APG) and the variation in the number of ethylene oxide groups (EOG) in the molecule] on the kinetics of zinc dissolution at 50 °C in 0.5 M H 2SO 4 containing impurities more positive than zinc (Co, Sb and Ge) was studied. It was found that nonylphenyl-polyethylene glycol with 15 EOG and APG in the molecule (S1), polyethylene glycols with 9 EOG (S2) and 45 EOG (S3) decrease zinc dissolution rate. The effect of surfactants decreases in order S1 > S3 > S2. The effect caused by the presence of nonylphenyl group in S1 surpasses that caused by the three times higher number of EOG in S3. The addition of S1 and S3 substantially inhibit the deposition (cementation) of impurities on zinc surface thus decreasing their effect on zinc dissolution. Zinc surface morphology was examined after dissolution using scanning electron microscopy (SEM). Due to S1 and S3 adsorption, zinc surface remains compact (without holes and cracks) which strikingly reduces the quantity of dissolved metal. The influence of S1 and S3 on zinc dissolution in the presence of Co, Sb and Ge confirms their inhibition effect on the negative action of above mentioned impurities during electrowinning stage in zinc hydrometallurgy.

Simultaneous determination of hydrolysable tannins in the petals of Rosa rugosa and allied plants

The petals of Rosa rugosa and allied plants for medicinal use contain abundant hydrolysable tannins, and they show remarkable biological activities. The activities are dependent on the structures of the hydrolysable tannins, so their contents and compositions are essential for evaluation of medicinal potency. Therefore, we optimized the simultaneous quantitative determination of the hydrolysable tannins using ultra-performance liquid chromatography. A column of ethylene bridged hybrid (BEH) phenyl (C(6) alkyl phenyl group as solid-phase modification) was shown to be most effective for the separation of hydrolysable tannins isolated from R. rugosa and related compounds when the column temperature was kept under 25 degrees C. The efficacy of the BEH phenyl column might be due to the interaction between solid phase and phenolic ester groups of hydrolysable tannins such as galloyl, hexahydroxydiphenoyl and valoneoyl groups. The relation between the retention times on the BEH phenyl column and the column temperature was demonstrated to depend on the structural characteristics of hydrolysable tannins.

Conjugated Oligoyne-Bridged [60]Fullerene Molecular Dumbbells: Syntheses and Thermal and Morphological Properties

A series of linear and star-shaped pi-conjugated oligomer hybrids (2-5) composed of an oligoyne core, ranging from 1,3-butadiyne to 1,3,5,7,9,11-dodecahexayne, and fullerenyl end-capping groups has been synthesized and studied. The molecular structures of these fullerene-oligoyne hybrids were assembled through three key reactions: Pd-catalyzed cross-coupling, Cu-catalyzed oxidative homocoupling, and an in situ alkynylation reaction on [60]fullerene. The properties of these compounds were investigated by UV-vis spectroscopy, differential scanning calorimetry (DSC), and atomic force microscopy (AFM) with the purpose of understanding the thermal reactivity arising from the oligoyne moieties as well as the morphological properties on surface. Our study shows that these fullerene-oligoyne hybrids tend to aggregate in different morphologies, including nanospheres, nanoflakes, and continuous thin films, while the morphological properties appear to be subject to the influence of molecular factors such as oligomer chain length, solubilizing alkylphenyl groups, and the thermal reactivity of the oligoyne unit. The correlation between molecular property and interfacial aggregation behavior evinced by these fullerene-oligoyne hybrids suggests a viable approach to exert bottom-up control over the structures and properties of fullerene based nanomaterials.

Solution processible naphthalene and perylene bisimides: Synthesis, electrochemical characterization and application to organic field effect transistors (OFETs) fabrication

A series of alkyl- or alkylphenyl-1,4,5,8-naphthalenetetracarboxylic-1,4:5,8-bisimides together with the comparative series of the corresponding 3,4,9,10-perylenetetracarboxylic-3,4:9,10-bisimides have been synthesized and characterized by cyclic voltammetry. The naphthalene bisimides family shows a clear dependence of its first reduction potential – corresponding to the LUMO level – on the nature of the N-substituent. Naphthalene bisimides containing alkylphenyl groups undergo the first 1e reduction at potentials of ca. 100 mV higher than those with alkyl groups ( ca. −900 mV vs ca. −1000 mV with respect to Fc/Fc + couple). No effect of the nature of the substituent is observed for the corresponding perylene bisimide series. Due to their improved solution processibility the synthesized organic semiconductors can be used for the fabrication of all organic, flexible n-channel field effect transistors (OFETs) through spin coating and printing techniques, without the necessity of the use of vacuum deposition techniques. The best of the fabricated transistors, operating in air show the charge carriers mobility of 4 × 10 −2 cm 2/(V s) and the ON/OFF ratio equal to 4.5 × 10 5.

Potential Role of Inhibiting the Vascular Endothelial Growth Factor Pathway in Advanced Prostate Cancer

Structural studies of topoisomerase-fluoroquinolone-DNA ternary complexes revealed a cavity between the quinolone N-1 position and the active site tyrosine. Fluoroquinolone derivatives having positively charged or aromatic moieties extended from the N-1 position were designed to probe for binding contacts with the phosphotyrosine residue in ternary complex. While alkylamine, alkylphthalimide, and alkylphenyl groups introduced at the N-1 position afforded derivatives that maintained modest inhibition of the supercoiling activity of DNA gyrase, none retained ability to poison DNA gyrase. Thus, the addition of a large and/or long moiety at the N-1 position disrupts ternary complex formation, and retained ability to inhibit supercoiling is likely through interference with the strand breakage reaction. Two derivatives were found to possess inhibitory effects on the decatenation activity of human topoisomerase II.

Synthesis of charge transporting polymer containing TPD units using Friedel–Crafts reaction

N, N′-bis(4-alkylphenyl)- N, N′-diphenylbenzidine (alkyl-TPD) was reacted with 1,4-bischloromethylbenzene, 9,10-bischloromethylanthracene (BCA), 4,4′-bis(chloromethyl)-1,1′-biphenyl (BCP) or 2,7-bis(bromomethyl)-9,9-di- n-butylfluorene (BBF) by condensation polymerization using Friedel–Crafts reaction. The polymers were obtained in high yield and high molecular weight. TPD having two methyl substituents showed higher reactivity and larger gel content than one having two butyl substituents. The structure of polymers was determined by 1 H NMR spectroscopy. It was found that all polymers showing two methylene signals arises from benzyl proton, which indicates that the polymerization occurred not only at the para-position of phenyl group but also at the meta-position of alkylphenyl group in TPD derivatives. All polymers had almost the same oxidation potential as that of TPD itself. The polymer containing anthracene unit showed not only oxidation but also reduction peak.

Spectrophotometric determination of nonionic surfactants by flow injection analysis utilizing ion-pair extraction and an improved phase separator

The proposed flow-injection determination of nonionic surfactants of the general type RO(CH 2CH 2O) nH (where R is an alkyl or alkylphenyl group and n is the number of moles of oxyethylene group) is based on extraction of the colored ion-pair product formed between the nonionic surfactant and the regent tetrabromophenolphthalein ethyl ester potassium salt (TBPE-K). The complex is extracted into 1,2-dichloroethane and measured at 609 nm. A new phase separator is described. Triton X-100 is used as a model compounds, for which response is linear in the range 2–60 mg l −1. Precision of the method is excellent with a relative standard deviation of <1.0%. The sensitivity of the method depends on the type of surfactant examined.

Extractive spectrophotometric determination of non-ionic surfactants in water

The solvent extraction of non-ionic surfactants with potassium chloride and tetrabromophenolphthalein ethyl ester potassium salt has been studied, and a method developed for determining trace amounts of non-ionic surfactants in water spectrophotometrically. Various non-ionic surfactants of general type RO(CH 2CH 2O) n H (where R is an alkyl or alkylphenyl group and n is the number-average degree of polymerization) are extracted quantitatively into o-dichlorobenzene from the water sample, and reacted in the organic phase with tetrabromophenolphthalein ethyl ester potassium salt to give a coloured product, the absorbance of which is measured at 620 nm.

Determination of polyoxyethylene alkylphenyl ether non-ionic surfactants in waters.

A method is proposed for the determination of polyoxyethylene alkylphenyl ethers, RO(CH2CH2O)nH (where R is an alkylphenyl group), at the 1–0.1 mg l–1 level in waters. The method is based on the spectrophotometric determination of the complexes of the polyethers with the sodium cation after extraction as picrates into 1,2-dichloroethane. The number-average degree of polymerisation (text-decoration:overlinen) is evaluated by thin-layer chromatography or by gas chromatography.The method was tested on commercial compounds that have R =p-tert-nonylphenyl (3.3 ⩽text-decoration:overlinen⩽ 21.5). For typical surfactants (6.5 ⩽text-decoration:overlinen⩽ 21.5) the proposed method is about eight times more sensitive than that based on the ammonium tetrathioisocyanatocobaltate(II) reagent and it gives results for the absolute concentration with an accuracy ranging from –6 to +8 per cent. in the indicated interval of text-decoration:overlinen. The precision was evaluated from the analysis of waste waters. A few interferences are discussed.