Phenyl Side Research Articles

Triphenylphosphine─Closed-Shell Metal Cation Interactions.

The interactions between group 1 and 11 monocations and group 2 dications with triphenylphosphine were studied by using a combination of correlated molecular orbital theory and density functional theory. Two binding modes were found: the front side (phosphorus lone pair) and back side (phenyl rings). Group 1 and 2 cations prefer binding to the π system rather than to the lone pair of the phosphorus atom, and their ligand binding energies (LBEs) correlate with the atomic ionic radii as well as the hardness of the atomic ion. Group 11 monocations prefer binding to the lone pair of the phosphorus atom, and their LBEs are correlated with the hardness of the cation but exhibit a different trend than for the groups 1 and 2 cations. The LBEs of the cations with C2H4, C6H6, and C6H5PH2 are also reported to aid in the analysis of the cation-π interactions and the influence of the PH2 substituent on the energy of this interaction. The LBEs for binding to C2H4 and C6H6 are the most complete and reliable set of values for these species.

Fine‐Tuning Alkyl Chains on Quinoxaline Nonfullerene Acceptors Enables High‐Efficiency Ternary Organic Solar Cells with Optimizing Molecular Stacking and Reducing Energy Loss

AbstractMaterial design of guest acceptor is always a big challenge for improving the efficiency of ternary organic solar cells (OSCs). Here, a pair of isomeric nonfullerene acceptors based on quinoxaline core, Qx–p‐C7H8O and Qx–m‐C7H8O, is designed and synthesized. By moving the alkoxy chain attached on side phenyl from meta‐position to para‐position, both π–π stacking distance and crystallinity are enhanced simultaneously. They obtain the uplifted lowest unoccupied molecular orbital level. Compared to Qx–m‐C7H8O, Qx–p‐C7H8O exhibits wider absorption spectrum and higher extinction coefficient. Using D18‐Cl:N3 as host materials, the addition of guest acceptor Qx–p‐C7H8O significantly improves the power conversion efficiency (PCE) from 17.61% to 18.49% because of higher open‐circuit voltage (0.875 V) and short‐circuit current density (27.85 mA cm−2). This can be attributed to the faster exciton dissociation, more balanced carrier mobility, fine fiber morphology, and lower energy loss in the ternary devices. However, Qx–m‐C7H8O‐based ternary device achieves relatively low PCE of 17.17% because this device shows extremely low electron mobility. The results indicate that molecular stacking, film morphology, etc., can be effectively modulated by fine‐tuning the side chains of guest materials, which may be an effective design rule for further improving the PCE of OSCs.

Solvent Extraction and Conformation Rigidity: Actinide(IV) and Actinide(VI) Come Together.

The first comprehensive structural and extraction study of a 2,2'-bipyridine-6,6'-dicarboxamide (L diamide) extractant for U, Np, Pu, Th, Am, and Eu ions showed great potential for actinide separation due to steric hindrance of the amidic side phenyl ring of the given compound. The study of the complexes of An(VI) and Th(IV) with 2,2'-bipyridyldicarboxamide-type extractants demonstrated the structure of the extraction species for the first time. Investigation of the extraction properties with the radiometric and millimolar quantities of actinides showed similar extraction trends. For the first time, a metal-ion-induced phenyl-ring rotation restriction was found for the U, Th, and Eu complexes by employing temperature-dependent dynamic NMR. A study of the solution behavior of the complexes accompanied by density functional theory modeling studies elucidated the mechanism of the unusual C-N bond rotation restriction induced by metal coordination.

Assessing pyrolysis behavior of silicon-containing arylacetylene resin via experiments and ReaxFF MD simulations

Silicon-containing arylacetylene resin (PSA), a thermosetting organic-inorganic hybrid resin of high heat-resistance performs well in ablation process, whereas its pyrolysis behavior under high temperature has not been fully interpreted. Herein, the PSA pyrolysis process was in-depth investigated by experiments and ReaxFF molecular dynamics simulation (ReaxFF-MD). TG results show that the temperature of 5% weight loss (Td5) is above 600 ℃, and the residue at 900 ℃ surpass 85%, demonstrating PSA has excellent heat resistance and thermal stability. The on-line FTIR and out-line gas quantify analysis reveals that H2 and CH4 are dominant gaseous products, which are also unveiled by ReaxFF-MD simulation. Molecular reaction tracking indicates PSA pyrolysis is initiated by the cleavage of skeleton in benzene ring, the cleavage of C-C bond and C-Si bond in main chain at elevated temperature. Hydrogen abstraction reactions are primary formation pathways of CH4 and H2, together with conquering high energy barriers. The activation energy of PSA pyrolysis in experiments is 155 kJ/mol, agreeing well with that from ReaxFF MD simulations (144 kJ/mol), which further confirms the thermochemical stability of cured PSA that rich in highly crosslinked aromatic structure. Besides, the influence of silicon side-groups on PSA pyrolysis is screened by MD and results indicate that gases evolution depended largely on side-groups types and decreasing side phenyl groups in PSA is benefit for improving its thermal stability. This work deepens the understanding of PSA pyrolysis mechanism and provides theoretical guidance for improving its heat resistance.

New Prospective Phosphodiesterase Inhibitors: Phosphorylated Oxazole Derivatives in Treatment of Hypertension.

Purpose: One of the promising chemical groups for the development of new antihypertensive medicines, the action of which is associated with the inhibition of phosphodiesterase III (PDE3) activity, are phosphorylated oxazole derivatives (OVPs). This study aimed to prove experimentally the presence of the OVPs antihypertensive effect associated with decreasing of PDE activity and to justify its molecular mechanism. Methods: An experimental study of the effect of OVPs on phosphodiesterase activity was performed on Wistar rats. Determination of PDE activity was performed by fluorimetric method using umbelliferon in blood serum and organs. The docking method was used to investigate the potential molecular mechanisms of the antihypertensive action of OVPs with PDE3. Results: The introduction of OVP-1 50 mg/kg, as a leader compound, led to the restoration of PDE activity in the aorta, heart and serum of rats with hypertension to the values observed in the intact group. This may indicate the possibility of the development of vasodilating action of OVPs by the influence of the latter on the increase in cGMP synthesis due to inhibition of PDE activity. The calculated results of molecular docking of ligands OVPs to the active site of PDE3 showed that all test compounds have a common type of complexation due to phosphonate groups, piperidine rings, side and terminal phenyl and methylphenyl groups. Conclusion: The analysis of the obtained results both in vivo and in silico showed that phosphorylated oxazole derivatives represent a new platform for further studies as phosphodiesterase III inhibitors with antihypertensive activity.

Effect of side groups on the properties of silicon‐containing arylacetylene resins

AbstractFour silicon‐containing arylacetylene resins were synthesized by polycondensation of Grignard reagent of m‐diethynylbenzene with methylethyldichlorosilane, dimethyldichlorosilane, methylphenyldichlorosilane, and diphenyldichlorosilane, respectively. The structures of the resins were verified by nuclear magnetic resonance spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The solubility, crystallinity, and rheological character of the resins were characterized. The curing behavior was traced by differential scanning calorimetry (DSC) and FTIR analyses. The effect of the side groups on the silicon atom on the properties was investigated. The results show that the resins with asymmetrical side groups display better processability (wide processing window) as compared with those with symmetrical side groups. The resin with side phenyl groups shows higher flexural strength but lower thermal stability as compared with those without side phenyl groups. Meanwhile, the side phenyl groups also enhance the temperature at which secondary relaxation occurs.

Synthesis, Anti-Proliferative Evaluation and Mechanism of 4-Trifluoro Methoxy Proguanil Derivatives with Various Carbon Chain Length.

Among the known biguanide drugs, proguanil has the best antiproliferative activity. In contrast, newly synthesized biguanide derivatives containing fluorine atoms have excellent biological activity, among which trifluoromethoxy compounds show the strongest ability. Preliminary work in our laboratory exhibited that n-heptyl containing proguanil derivatives on one alkyl chain side have better biological activity than those with a shorter carbon chain. However, the relationship between the length of the carbon chain and the activity of the compounds is unknown. In this study, we synthesized 10 new trifluoromethoxy-containing proguanil derivatives with various carbon chain lengths. The phenyl side is fixed as the trifluoromethoxy group with change of carbon chain length in alkyl chain side. It was found that the anti-cancer abilities of 5C–8C with n-pentyl to n-octyl groups was significantly better than that of proguanil in the five human cancer cell lines. The colony formation assay demonstrated that 6C–8C at 0.5 to 1.0 μM significantly inhibited the colony formation of human cancer cell lines, much stronger than that of proguanil. Pharmacologically, 8C activates AMPK, leading to inactivation of the mTOR/p70S6K/4EBP1 pathway. Thus, these novel compounds have a great potential for developing new anti-cancer candidates.

Poly(aryl ether ketone ketone)s containing diphenyl-biphthalazin-dione moieties with excellent thermo-mechanical performance and solubility

High molecular weight poly(aryl ether ketone ketone)s comprising diphenyl-biphthalazin-dione moieties (P-MDs) were prepared through the solution condensation. The structure of polymers was characterized via nuclear magnetic resonance spectra and infrared absorption spectrum. The effects of mixed diphenyl-biphthalazin-dione (mDBD) monomer on performance of polymers were investigated. The mDBD units containing side phenyl groups endow polymer with solubility and controllable contact angle. The resultant polymers perform a fine thermo-stability in both nitrogen and air, presenting an excellent thermal resistance with glass transition temperature in the range of 253–333 °C. Simultaneously, the polymers exhibit a favorable solubility in 1,1,2,2-tetrachloroethane and N-methylpyrrolidone, showing fine film-formation performance. Polymers possess excellent mechanic performance with the tensile strength up to 84 MPa, the Young’s modulus above 1.5 GPa and the retention of storage modulus at 250 °C as high as 70%. Additionally, the contact angle of water-drops with polymer films is within the range of 73.5°–89.1°.

Control of Intramolecular Hydrogen Bonding in a Conformation-Switchable Helical-Spring Polymer by Solvent and Temperature.

A substituted poly(phenylacetylene) derivative (PPAHB ) with two hydroxymethyl groups at the meta position of the side phenyl ring was examined as a conformation-switchable helical spring polymer that responds to solvent and heat stimuli in a precisely controlled manner. Intramolecular hydrogen bonds, which cause the helical structure of the polymer, were broken and re-formed by adjusting the hydrogen-bonding strength values (pKHB ) of various combinations of solvents or by varying the temperature. In this process, a reversible conformational change from cis-cisoid to cis-transoid, accompanied by a phase transition in the form of a helix-coil transformation occurred, with the polymer exhibiting critical changes of color fading and recovery in specific environments. These results demonstrate that PPAHB can be used as either a pKHB indicator or a thermometer. The color changes of the polymer solution are described in detail based on spectroscopic analyses and thermodynamic considerations.

Control of Intramolecular Hydrogen Bonding in a Conformation‐Switchable Helical‐Spring Polymer by Solvent and Temperature

AbstractA substituted poly(phenylacetylene) derivative (PPAHB) with two hydroxymethyl groups at the meta position of the side phenyl ring was examined as a conformation‐switchable helical spring polymer that responds to solvent and heat stimuli in a precisely controlled manner. Intramolecular hydrogen bonds, which cause the helical structure of the polymer, were broken and re‐formed by adjusting the hydrogen‐bonding strength values (pKHB) of various combinations of solvents or by varying the temperature. In this process, a reversible conformational change from cis–cisoid to cis–transoid, accompanied by a phase transition in the form of a helix‐coil transformation occurred, with the polymer exhibiting critical changes of color fading and recovery in specific environments. These results demonstrate that PPAHB can be used as either a pKHB indicator or a thermometer. The color changes of the polymer solution are described in detail based on spectroscopic analyses and thermodynamic considerations.

Optimization of oxadiazole derivatives with a spirocyclic cyclohexane structure as novel GPR119 agonists

We describe here a novel GPR119 agonist 24, which showed a potent and long-acting hypoglycemic effect in rats via oral dosing. For the discovery of 24, we chose compound 5, which possessed an oxadiazole linker, as a lead compound among our spirocyclic cyclohexane GPR119 agonist series, taking into account its lower plasma protein binding nature. 3,5-Difluoro and 4-methylsulfonylmethy groups on the left side phenyl group, and a gem-difluoro group on the right side of 24 are important for its agonist potency and metabolic stability, respectively.

Synthesis and mesomorphic properties of four ring, rod-like fluorene derivatives – the influence of the lateral substitution on mesomorphic properties of 2,7-bis(4-alkylphenyl)-fluorenes

ABSTRACTThis work presents new rod-like compounds being fluorene derivatives linked with other parts of the core at 2 and 7 positions – its synthesis and properties. The fluorene moiety is located in the central position of the four rings molecular core. The chain system in most cases was symmetrical and limited to pentyl or hexyl chains. To study the influence of the lateral substituents on mesomorphic properties two types of substituents have been incorporated, centrally located various short alkyl groups at fluorene’s 9,9 positions and outer core fluorosubstitutions located at side phenyl rings. All synthesised compounds exhibit liquid crystalline properties, where for laterally non-substituted and fluorosubstituted derivatives the dominant phases are smectics, while the nematics phases (nematic and chiral nematic – observed mostly on cooling cycle) occurs for compounds having alkyl substituents at 9,9 positions of fluorene. The synthetic methodology and mesomorphic properties of title compounds will be presented in detail as well as photophysical properties such as UV-visible absorption spectra and fluorescence spectra.

N-[2-(Tri-fluoro-meth-yl)phen-yl]maleamic acid: crystal structure and Hirshfeld surface analysis.

The title mol-ecule, C11H8F3NO3, adopts a cis configuration across the -C=C- double bond in the side chain and the dihedral angle between the phenyl ring and side chain is 47.35 (1)°. The -COOH group adopts a syn conformation (O=C-O-H = 0°), unlike the anti conformation observed in related maleamic acids. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds are connected via N-H⋯O hydrogen bonds and C-H⋯O inter-actions into (100) sheets, which are cross-linked by another C-H⋯O inter-action to result in a three-dimensional network. The Hirshfeld surface fingerprint plots show that the highest contribution to surface contacts arises from O⋯H/H⋯O contacts (26.5%) followed by H⋯F/F⋯H (23.4%) and H⋯H (17.3%).

Catalytic performance of bis(imino)pyridine Fe/Co complexes toward ethylene polymerization by 2D‐/3D‐QSPR modeling

The two-dimensional and three-dimensional quantitative structure-property relationship (2D- and 3D-QSPR) approaches are applied to investigate the catalytic performance for a total data set of 55 bis(imino)pryridine iron and cobalt complexes, including the catalytic activity, molecular weight, and melting temperature of the product. The obtained models for the catalytic performance of interest exhibit good results by both 2D- and 3D-QSPR modeling, meanwhile higher predictive and validation powers observed in the 3D type. The modeling results indicate that the bulky substituents on ortho-position of the singular side phenyl ring and positive charge on para-position of the phenyl ring within the ligand are favorable to catalytic activity, while unfavorable to the molecular weight of product. Based on the obtained QSPR models, four new complexes are designed and predicted with good catalytic activity and very high molecular weight, which are in good agreement with our recent experimental report. © 2019 Wiley Periodicals, Inc.

Viscosity measurement of silicone oils based on diffusion rates in polydiphenylacetylene films

Polydiphenylacetylene derivatives with different alkyl side chains (methyl, ethyl, and n-propyl groups) via a silylene linkage (PDPA-C1, PDPA-C2, PDPA-C3) were prepared. The polymer films were examined as a solid-state sensor for measuring the viscosity of silicone oils based on the diffusion rate in the films. When the films were brought into contact with silicone oils, the fluorescence (FL) emission increased with time to reach an FL enhancing equilibrium. PDPA-C1 showed faster and more significant FL enhancement because of the larger free volume and higher degree of side phenyl stacking. The relationship between the time to reach FL enhancing equilibrium (teq) and silicone oil viscosity (η) was well expressed by a modified Forster-Hoffmann equation: log teq = C + x log η, where x is the probe-dependent constant. The slope x values, which indicate viscosity sensitivity, were 0.37 for PDPA-C1, 0.35 for PDPA-C2, and 0.36 for PDPA-C3 in thin films and 1.15 for PDPA-C1 in a thick film, indicating high viscosity sensitivity depending on film thickness. The relationship between probe FL intensity and fluid viscosity, typically expressed by the Forster-Hoffmann equation, was never established in this system. The viscosity determination method using the modified Forster-Hoffmann equation proved very useful for identifying unknown viscosities of commercial silicone oils.

Sequential Induction of Chirality in Helical Polymers: From the Stereocenter to the Achiral Solvent.

Several steps of chiral induction have been detected in poly(phenylacetylene)s among their different hierarchical levels of chirality by vibrational circular dichroism, namely, (i) from the stereogenic centers to the innermost polyacetylene helical covalent backbone (helixint), (ii) from this to the external helix (helixext) formed by the side phenyl pendants that form a complementary helix or counter-helix, and (iii) from this pendant helix to the helical solvation sphere (helixsolv.), the last one being observed along this work. The pendant to polyene backbone chiral induction determines the helical structure adopted by the polymer and therefore the solvation helix. This helical structure is promoted by two mechanisms: steric effects and hydrogen bonding. An important finding concerns the demonstration by VCD of how an achiral solvent becomes chirally organized owing to the template effect of the covalent polymer helices, an effect that is silent to other structural techniques such as ECD or AFM and that hence significantly broadens the scope of these previous analyses.

Twist of C═C Bond Plays a Crucial Role in the Quenching of AIE-Active Tetraphenylethene Derivatives in Solution

Aggregation-induced emission (AIE) has emerged as a new class of attractive photoluminescence behavior. Understanding the precise mechanism of the AIE phenomenon will lead to the rational molecular design of novel molecules with AIE properties (AIEgens). In this work, we selected disubstituted derivatives of tetraphenylethene (TPE), a well-known archetypal AIEgen, as the model compounds to elucidate the AIE mechanism. As the result of photochemical experiments and quantum chemical computations, π-bond twist (π twist), including E–Z isomerization (EZI), was found to be the major factor for quenching the photoexcited state of TPE derivatives in the solution state, differently from the well-accepted propeller-like rotation of the side phenyl groups in earlier research. In photochemical experiments, the prepared TPE derivatives exhibited EZI in the solution state upon photoirradiation, and a negative correlation was observed between this isomerization and the AIE phenomenon. The theoretical computations verif...

Kinetic Study on Achiral-to-Chiral Transformation of Achiral Poly(diphenylacetylene)s via Thermal Annealing in Chiral Solvent: Molecular Design Guideline for Conformational Change toward Optically Dissymmetric Structures

Achiral poly(diphenylacetylene)s (PDPAs: pMe3, pEt3, piPr3, pMe2O1, pMe2OD1, and mMe3) with different alkyl side chains at the para or meta position of the side phenyl ring were prepared to examine achiral-to-chiral transformations upon thermal annealing in a chiral solvent. All the para-substituted PDPAs showed significant circular dichroism (CD) enhancement upon annealing, whereas the meta-substituted polymer, mMe3, was inert to the same treatment. To investigate the kinetics, the asymmetric conformational change was monitored by observing the changes in the magnitude of circular polarization (gCD) or optical rotation. PDPAs with bulkier, round-shaped side groups (pEt3 and piPr3) had greater gCD values at equilibrium than pMe3 with a smaller side group. Moreover, the activation energy for the forward reaction (Eaf) was lower in the bulkier polymers than in pMe3 owing to enhanced miscibility with the chiral solvent. Similarly, the long alkyl chains of pMe2O1 and pMe2OD1 acted as internal plasticizers to ...

Annealing-Induced Circular Dichroism Enhancement in Luminescent Conjugated Polymers with an Intramolecular Stack Structure

Two poly(diphenylacetylene) derivatives containing identical chiral pinanyl groups on the para- and meta-positions of the side phenyl ring were prepared, and their circular dichroism (CD) and photoluminescence (PL) spectra were compared. The magnitudes of circular polarization (gCD) of the para- and meta-polymers were determined to be 3.1 × 10–3 and 1.4 × 10–3, respectively. The PL quantum yield (PLQY) of the para-polymer was much greater (27.8%) than that of the meta-polymer (2.61%). When the two polymers were annealed at 80 °C in toluene, their CD spectra were remarkably enhanced and reached equilibrium at gCD values of 9.6 × 10–3 and 6.0 × 10–3, respectively. The para-polymer was kinetically more favored for the CD enhancement as known from the fact that the activation energies for the reactions of para- and meta-polymers were determined to be 88 and 187 kJ mol–1, respectively. The PLQYs of both polymers were unaffected by annealing.

Quantum chemical study on phenethylamines reveals new cation structures

Phenethylamines are compounds known by their psychoactive and stimulant effects. Their physiological activity is strongly conformer dependent. In this work, the quantum chemical investigation of neutral and cationic phenylethylamine, amphetamine and methamphetamine was performed in order to determine the most stable physiologically relevant conformers. Calculations were performed employing density functional theory and ωB97XD functional. A previously unknown double-ring cation structure formed by cyclization of aliphatic tail was found for all three molecular species. Calculations performed on several levels of theory reveal significant stability of these double-ring cations relative to other conformers. The transition state structures and energies for the cyclization reactions have been determined. Their stability and structural properties are discussed, as well as the possibility for their experimental observation. The significance of dispersion and NH⋯π interactions between side chain and phenyl ring on stability of phenethylamines and their charged forms were pointed out.