Bis Phenyl Research Articles

Role of Bimolecular Homolytic Substitution (SH2) Reactions in Free Radical Photopolymerization Under Air

A set of multivalent atom-containing amines (e.g., tetrakis(dimethylamido)silane, tetrakis(dimethylamido)tin(IV), tetrakis(diethylamido)titanium(IV), tetrakis(dimethylamido)zirconium(IV), and 1,3,5-triaza-7-phosphaadamantane) are proposed as new coinitiators in Type II photoinitiating systems (based, for example, on benzophenone) and additives for Type I photoinitiators (such as phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone) for free radical photopolymerization under air. The polymerization rates (Rp’s) were determined under experimental conditions where a strong detrimental oxygen effect is expected, that is, both under low light intensity and in thin low viscosity monomer samples. The remarkable performance achieved under air (up to a 100- and a 5-fold increase in Rp and final conversion (%), respectively) lies on the presence of a bimolecular homolytic substitution (SH2) reaction that allows us to convert peroxyls into new initiating radicals efficiently. The mechanisms are investigated by laser flash photolysis (LFP) and electron spin resonance (ESR) experiments.

Conductivity of AOT/Triton X-100 Mixed Reverse Micelles

采用聚乙二醇辛基苯基醚（TritonX-100）和二（2-乙基己基）琥珀酸磺酸钠（AOT）双表面活性剂,与正己烷、正己醇和水构成混合反胶束体系;研究了表面活性剂质量比、助表面活性剂含量、水油体积比和温度等因素对反胶束体系导电性能的影响,同时采用循环伏安法研究了K3Fe（CN）6/K4Fe（CN）6在该体系中的电化学行为.结果表明：由两种表面活性剂构成的反胶束体系电导率σ明显大于单一表面活性剂反胶束体系电导率;体系电导率随AOT与TritonX-100的质量比w（w=mAOT∶mTritonX-100）的变化而变化,w为0-0.4时,电导率随w增大而线性增大,之后增加趋势变缓;w=0.96时,σ达到稳定值576μS·cm-1.混合体系电导率随溶水量的增大及温度的上升而提高;而增加助表面活性剂可显著降低体系的电导率.在所研究体系中,Fe（CN）36-/Fe（CN）46-电化学反应对的氧化还原峰电位几乎不随扫描速率变化,峰电位差约为75mV,峰电流的比值约为1,氧化峰电流与扫描速率的平方根成正比,说明K3Fe（CN）6/K4Fe（CN）6在混合反胶束体系中显示出良好的氧化还原可逆性,反应由扩散步骤控制.

Bismaleimide Modified Epoxy-Diallylbisphenol System – Effect of Bismaleimide Nature on Properties

The properties of the ternary matrix system (EPB), obtained by the reactive blending of epoxy resin - diallyl bisphenol and a bismaleimide, depend on the structure and properties of its components. The influence of the structural variations of bismaleimide on the thermal, physical and mechanical properties of the ternary blend was examined. EPB compositions were prepared using novolac epoxy, diallyl phenol A and three different bismaleimide systems viz. 2, 2-bis 4-(4 maleimidophenoxy) phenyl propane-BMIP, bis (4-maleimidophenyl) methane-BMIM and bis (4-maleimido phenyl) ether-BMIE. The EPB systems with different types of bismaleimides were processed and characterized for their thermal, physical and rheological properties. EPB-glass composites processed using these matrix systems were characterized for their thermo-physical and mechanical properties. High temperature properties of these systems were assessed by their adhesive strength retention at different temperatures. The EPB system formed by the reactive blending of epoxy- phenol system with BMIP was found to yield the blend with improved mechanical performance at ambient conditions, while that with BMIM proved to be the best for high temperature application.

Anion binding properties of indolylmethanes

The anion binding properties of the indolylmethanes (1) were investigated by 1H-NMR spectroscopy in CDCl3. Tris(3-methylindol-2-yl)methane (1a) selectively bound a chloride anion the over other tested anions (Br−, I−, HSO4−, and NO3−). In contrast, analogous compounds, phenyl bis(3-methylindol-2-yl)methane (1b), 2-hydroxyphenyl bis(3-methylindol-2-yl)methane (1c), tri(indol-3-yl)methane (1d), and phenyl di(indol-2-yl)methane (1e), showed a low anion binding ability and selectivity. These results indicate that the number and a position of the binding sites (indole NH protons) of the indolylmethanes are important factors for the formation of the complex with an anion. The high binding ability and selectivity of 1a toward a chloride anion is attributed to the proper size of the binding pocket for a chloride anion and the formation of multiple hydrogen bonds between the three indole NH protons and a chloride anion. The anion affinity of 1a was significantly affected by the cation component of quaternary ammonium salts, indicating that it is ion pair binding and not solely anion binding.

Potentiometric and Spectrophotometric Studies of Copper(II) Complexes of Some Ligands in Aqueous and Nonaqueous Solution

AbstractStoichiometry and equilibrium study of copper‐ligands including mercaptobenzoxazole (MBO), 4‐propyl 2‐thiouracyl (PTU), methyl‐2‐pyridylketone oxime (MPKO), phenyl‐2‐pyridylketone oxime (PPKO), 4,6‐dihydroxy‐2‐mercaptopyrimidine (DHMP), N,N′‐phenylene bis(salicylaldimine) (PBS) and 1,2‐bis(2‐hydroxyphenyl)naphtaldiimine (BHNPDI) were conducted in aqueous and nonaqueous solution by potentiometry and spectrophotometry. Stability constants of the complexes are determined at 25 ± 1 °C and 0.1 or 0.05 M ionic strength in water or acetonitrile solvents. Oximes ligand protonation constants and copper‐ligands complexes' stability and hydrolysis constants were calculated using the BEST program in aqueous solution. The stability constants of copper‐ligands complexes were calculated using the KINFIT program in acetonitrile solution. The results of these two methods are made self‐consistent, then rationalized assuming an equilibrium model including the species, ML, MLH, MLOH and ML2 (where the charges of the species have been ignored for the sake of simplicity) (L = MBO, PTU, MPKO, PPKO, DHMP, BHNPDI and PBS).

Characterization and solubility measurement and prediction of selected arylamines in hexane, methanol and benzene

The solubility of nine arylamine molecules in benzene, methanol and hexane was measured. These molecules were: triphenylamine, N -(4-methyl phenyl) N , N bis phenyl amine, N -(3-methyl phenyl) N , N bis phenyl amine, N , N -bis(4-methyl phenyl) N -phenyl amine, N , N -bis(3-methyl phenyl) N -phenyl amine, tritolylamine ( N , N , N -tris-(4-methylphenyl)amine), N , N -bis-(4-methylphenyl)- N -(3-methylphenyl)amine, N , N -bis-(3-methylphenyl)- N -(4-methylphenyl)amine, and N , N , N -tris-(3-methylphenyl)amine. The solubility of these molecules was estimated using ideal solution theory, the Hildebrand equation, and UNIQUAC method. The ideal solution theory and the Hildebrand equation were not able to estimate solubility with high precision. However, UNIQUAC method was able to estimate the solubility with good accuracy. It was found that substitution of methyl group regardless of its number in aryl ring increases the solubility. In addition, meta-substitution always results in higher solubility regardless of the nature of the solvent. Physical properties, as well as electrochemical properties of these materials were also provided. Based on these data, the most promising candidates for device preparation should be: mTTA, TTA, mmmTTA, and mono-TPA. However, the only way to prove the above ranking would be to test the candidates in actual devices, which is outside the scope of this paper.

Dithioesters in atom-transfer radical polymerization

Phenyl dithioacetates and bis(isobutyl) dithiocarbamates of Cu(II) and Ti(IV) were studied as chain-transfer agents in the controlled free-radical polymerization of methyl methacrylate and styrene. It was shown that the above compounds strongly decelerate the polymerization of at least one of the monomers. When Cu(II) bis(isobutyl) dithiocarbamate was used in an equivalent ratio with an initiator, the polymerization of MMA proceeded as a well-controlled process and yielded a monodisperse polymer. In other cases, when the concentration of the salt was reduced by two or more times, the most reliable feature of controlled polymerization was observed; that is, the molecular mass of the polymer increased linearly and progressively with an increase in the monomer conversion. The results obtained confirmed that dithiocarboxylate and dithiocarbamate groups can, similarly to halides, interact with transition-metal compounds through ligand-(atom)-transfer redox reactions.

Synthesis and characterization of a free phenylene bis(N-heterocyclic carbene) and its di-Rh complex: Catalytic activity of the di-Rh and CCC–NHC Rh pincer complexes in intermolecular hydrosilylation of alkynes

1,3-Bis(3-butylimidazolium-1-yl)benzene diiodide ( 1) was reacted with Li(2,2,6,6-tetramethylpiperidine) yielding the free bis-carbene, 1,3-bis(3-butylimidazol-2-ylidene-1-yl)benzene ( 3), which has been spectroscopically characterized. Combining the free bis-carbene with [Rh(COD)Cl] 2 yielded the corresponding di-Rh bis(N-heterocyclic carbene) complex ( 4) that was structurally characterized. The di-Rh bis-carbene complex was found to exhibit complex solution 13C and 1H NMR spectra that have been assigned as a mixture of diastereomers. The crystal structure of the di-Rh bis-carbene compound 4 was composed of a pair of enantiomeric atropisomers. The diastereomeric atropisomers were assigned as the source of the spectral complexities. The di-Rh di-carbene complex 4 and the CCC–NHC Rh pincer complex 2 were applied as catalysts in hydrosilylation reactions of terminal and internal alkynes. Both catalysts are highly active, regioselective, stereoselective, and chemoselective: terminal alkynes give predominantly the β-( Z) isomer and internal alkynes afford the β-( E) isomer in chloroform or benzene. One of the strongest attributes of the catalyst systems is that the results were achieved without exclusion of air and without purification of commercially available reagents.

Structure and order of a homologous series of bent-core molecules: a 13C NMR study.

A carbon-13 NMR study in a series of bent-core (banana-shaped) molecules is reported. In 1, 3- phenylene bis[4'-alkenyloxy biphenyl]-4-carboxylate derivatives the position of the chlorine substituent(s) connected to the central phenyl ring and/or the terminal chain length of the compounds were varied. By analyzing the observed chemical shift anisotropies, the order parameters S and bending angles in their nematic phase are compared. The biphenyl moiety on each arm of the molecular core is found to form a nonzero twist angle.

The Characterization and Reactivity of Photochemically Generated Phenylene Bis(diradical) Species as Revealed by Matrix Isolation Spectroscopy and Computational Chemistry

AbstractFor Abstract see ChemInform Abstract in Full Text.

STUDIES ON PHASE SEPARATION OF POLYESTERIMIDE-MODIFIED EPOXY RESINS. I. SYNTHESES AND PROPERTIES OF ORGANO-SOLUBLE POLYESTERIMIDES

ABSTRACT A series of polyesterimides based on aromatic bis(trimellitate) dian-hydride in main chain were prepared by polycondensation of t-butyl-p-phenylenebis(trimellitate) dianhydride (BPBDA) and phenylene bis(trimellitate) dianhydride (PBDA) with benzidine and its derivates. The results show that the incorporation of noncoplanar structure led by introducing alkyl substituents on dianhydride and benzidine can improve the solubility of polyesterimides in organic solvents. It also displays that the introducing substituents lead to a decrease in glass transition temperature and influence the β relaxation of PEsI. By comparing the chemical structure and the dynamical mechanic date, we suggest that the β relaxation correspond to the motion involving the imide ring and phenylene groups of the diamine.

Adhesion Property of Novel Polyimides Containing Fluorine and Phosphine Oxide Moieties

ABSTRACTNovel diamine monomers, containing fluorine and phosphine oxide - bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide (mDA6FPPO) and bis(3-aminophenyl)-4-(trifluoromethyl)phenyl phosphine oxide (mDA3PPO) - were utilized to prepare polyimides with dianhydrides such as 6FDA, BTDA or ODPA by the conventional two-step route, i.e., preparation of poly(amic-acid), followed by solution imidization. Adhesion property of the polyimides was evaluated via a peel test with bare Cu foil, as well as Cr/silane coated Cu foils, and failure surfaces were analyzed by SEM/EDX to elucidate the adhesion mechanism. The polyimides with 3FDAm exhibited the highest Tg, followed by mDAPPO-, mDA3FPPO- and mDA6FPPO-based polyimides, but the mDAPPO-based polyimides exhibited the highest adhesion properties, followed by mDA3FPPO, mDA6FPPO, mDDS and 3FDAm, attributing to phosphine oxide and fluorine moieties.

Adhesion property of novel polyimides containing fluorine and phosphine oxide moieties

Novel diamine monomers containing fluorine and phosphine oxide - bis(3-aminophenyl)-3,5-bis(trifluoromethyl)phenyl phosphine oxide (mDA6FPPO) and bis(3-aminophenyl)-4-(trifluoromethyl)phenyl phosphine oxide (mDAFPPO) - were utilized to prepare polyimides with dianhydrides such as 6FDA, BTDA or ODPA by the conventional two-step route, i.e. preparation of poly(amic acid) followed by solution imidization. The polyimides were characterized by FT-IR, NMR, DSC, and intrinsic viscosity measurements. The adhesion property of the polyimides was evaluated via a peel test with bare Cu foil, as well as silane/Cr-coated Cu foil, and failure surfaces were analyzed by SEM/EDX to elucidate the failure mechanism. The results were compared with those from the polyimides prepared from bis(3-aminophenyl)phenyl phosphine oxide (mDAPPO) containing only the phosphine oxide moiety, 1,1-bis(4-aminophenyl)-1-phenyl-2,2-trifluoroethane (3FDAm) containing only the fluorine moiety, and a commercial 3,3′-diaminodiphenylsulfone (mDDS). The polyimides with 3FDAm exhibited the highest T g, followed by the mDAPPO-, mDA3FPPO-, and mDA6FPPO-based polyimides, but the mDAPPO-based polyimides exhibited the highest adhesion properties, followed by mDA3FPPO, mDA6FPPO, mDDS, and 3FDAm, which is attributed to the phosphine oxide and fluorine moieties.

Synthetic models for the zinc sites in the methionine synthases.

The syntheses and molecular structures of a series of tetrahedral zinc complexes designed to model the active sites in Escherichia coli methionine synthases are reported. [PhTttBu]ZnBr (PhTttBu = phenyltris((tert-butylthio)-methyl)borate) was prepared and characterized crystallographically to provide entry into [S3]ZnX complexes. Metathesis with KSPh yielded the phenylthiolato complex, [PhTttBu]Zn(SPh), which represents a structural mimic of the homocysteine ligated form of the enzyme. Alternatively, [S2N]ZnX (X = Br, CH3, SPh) species were prepared using the new mixed-donor ligands, [Ph(pz)BttBu] (phenyl(pyrazolyl)bis((tert-butylthio)methyl)borate) and [Ph(pztBu)BttBu] (phenyl(3-tert-butylpyrazolyl)bis((tert- butylthio)methyl)borate). Protonolysis of [Ph(pztBu)-BttBu]Zn(CH3) by PhSH in toluene yielded [Ph(pztBu)BttBu]Zn(SPh), a synthetic analogue of the homocysteine ligated form of cobalamin-independent methionine synthase (Met E). The average Zn-S bond distance in [Ph-(pztBu)BttBu]Zn(SPh) of 2.37 A compares well with the EXAFS-derived distance of 2.31 A found in the homocysteine-bound form of Met E.

Phase transition in the bidimensional compound [C6H5(CH2)2NH3]2CdCl4

Bis phenyl 2 ethylammonium lead tetrachloride ([C6H5(CH2)2NH3]2CdCl4) is a new member of the family of perovskite-type layer compounds. It exhibits a structural phase transition This transition is characterised by DSC measurements, X-ray diffraction, dielectric measurements and Raman scattering on polycrystalline samples. The space groups and the cell parameters of phases I and II were determined by X-ray diffraction on single crystals and powder samples. The phases I and II have the same space group Pcab with Z = 4. The transition is also of first order and involves both organic action motions and CdCl6 octahedral deformations. This transitional behaviour and the crystal dynamics will be discussed and compared with those found in the literature for homologous compounds.

Synthesis and characterization of phosphorus-containing methacrylate-based difunctional crosslinkers and their use in UV-curable resin systems

Two new phosphorus-containing methacrylate-based difunctional crosslinking agents (bis(4-(2-methacryloyloxy)ethyl carboxyl)phenyl phosphine oxide (BEPPPO) and bis(4-(2-methacryloyloxy)ethylcarbonylaminophenyl)phenyl phosphine oxide (BUPPPO)), which can be good candidates for UV-curable coating applications, were synthesized by reacting either a phosphorus-containing diisocyanate (bis(4-iso- cyanatophenyl)phenyl phosphine oxide) or a phosphorus-containing diacid chloride (bis(4-chloroformylphenyl)phenyl phosphine oxide) with hydroxyethyl methacrylate. The structures of the monomers thus obtained were characterized by FTIR, mass, and 1 H-NMR spectroscopies. The contents of the new crosslinking agents in the UV-cured polymeric films were varied between 10 and 30% by weight. Mechanical, physical, and thermal characterizations of the UV-cured films were investigated. An increase in crosslinking agent content caused an increse in mechanical properties. Films contain- ing BUPPPO had higher tensile strength values compared to the films containing BEPPPO. Thermogravimetric analysis of phosphorus-containing crosslinking agents revealed that incorporating phosphorus into the structure resulted in a high char yield up to 24.5% at 600°C. Water absorption values of UV-cured films were also affected by the amount and type of crosslinking agent. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2575-2585, 1999

Crystal and Molecular Structure of a Mesogenic Compound with a Large Lateral Benzene Ring-containing Substituent

Abstract The crystal and molecular structure of the nematic compound 4-nitrobenzyl 2,5-bis (4-ethyloxybenzoyloxy)-benzoate (NEBB) has been determined at −100°C and at room temperature by X-ray analysis. NEBB crystallizes in space group P 1 with two molecules in a unit cell of dimensions (values of the room temperature investigation are given in brackets) a = 9.547 (3) [9.643 (2)], b = 12.294 (4) [12.452 (3)], c = 13.536 (5) [13.660 (3)] A, α = 68.67 (3) [68.34(1)], β= 75.15 (3) [74.40 (1)], γ = 70.98 (3) [69.65 (1)]°. The structure was solved by direct methods and refined on F 2 to R values of wR2 = 0.107 [0.109] and R1 = 0.043 [0.049], respectively, for 3347 [2422] observed unique reflections. The phenylene bis(benzoate) basic core of the NEBB molecule has a non-planar but optimally stretched shape and the lateral ring-containing substituent is oriented parallel to it. The molecules in the crystalline state are arranged perfectly parallel to each other with an anti-parallel orientation of the neighbours....

Unsymmetrically disubstituted mesogens with a phenyl ring containing lateral branch. Crystal and molecular structure of smectogenic 4-nitrobenzyl 2-(3-chloro-4-n-octyloxybenzoyloxy)-5-(4-n-octyloxybenzoyloxy)benzoate

Abstract The synthesis of unsymmetrically disubstituted mesogens bearing a cyclic unit within the bulky lateral branch is described. The three-ring basic mesogenic unit of the laterally 4-nitrobenzyloxy-carbonyl substituted molecules has been additionally provided with chlorine atoms in one or two positions, thus influencing the stability of the smectic A phases. The crystal and molecular structure of the smectogenic 4-nitrobenzyl 2-(3-chloro-4-n-octyloxybenzoyloxy)-5-(4-n-octyloxybenzoyloxy)benzoate (NCOOB) has been determined by X-ray analysis. NCOOB crystallizes in the triclinic space group P1 with 4 molecules per unit cell and the following lattice parameters: a = 13.201(2) A, b = 16.473(3) A, c = 19.746(3) A, α = 96.11(2)°, β = 95.34(2)°, γ = 99.92(1)°, V = 4178.4(1) A3. The phenylene bis(n-octyloxybenzoate) mesogenic basic fragment of the NCOOB molecule has a non-planar, but optimally stretched shape, with a perfect all-trans-conformation of the alkyloxy chains and the lateral benzene ring-containin...

EXAFS study of some coordination polymers of copper

The EXAFS spectra for (1) azelaic acid bis phenyl hydrazide, (2) azelaic acid bis 2,4 dinitro phenyl hydrazide and (3) sebacic acid bis phenyl hydrazide coordination polymers of copper were obtained using the EXAFS facility of the Daresbury Laboratory. The EXAFS analysis revealed that copper is surrounded by four nitrogen and two oxygen atoms in the first coordination shell, while the second coordination shell consists of two carbon atoms. This information suggests the octahedral geometry for the repeating units of polymeric complexes, in contrast to the square planar geometry previously proposed.

CASSCF and CASPT2 calculations of hole-doped polycarbenes. Possibilities of organic ferromagnetic conductors and metals

Ab initio CASSCF and CASPT2 calculations were carried out for hole-doped polycarbenes such as monocations of bis(methylene)ethylene and phenylene bis(methylene) in order to confirm previous spin polarization and delocalization rules for ion-radicals. The ground state was calculated to be quartet for the hole-doped meta-phenylene bis(methylene). The high- and low-spin crossover by hole doping did not occur, being consistent with the ESR and ENDOR experiments for the monocation of meta-phenylene bis(phenylmethylene) by the Shida and Itoh-Takui groups. On the other hand, spin crossover by hole doping is concluded for bis(methylene)ethylene and para-phenylene bis(methylene) in accord with the previous spin delocalization effect. The implications of these results are discussed in relation to the possibilities of organic ferromagnetic conductors and metals.