Fluorinated <Emphasis Type="Italic">p</Emphasis>-<Emphasis Type="Italic">n</Emphasis> type copolyfluorene as polymer electret for stable nonvolatile organic transistor memory device

In this study, a kind of fluorinated copolyfluorene, named poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt-(2,3,5,6-tetrafluoro-1,4-phenylene)] (PODPF-TFP), is synthesized by facile palladium-based direct aromatization. Compared to the non-fluorinated counterpart, poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt-(p-phenylene)] (PODPF-P), deeper HOMO/LUMO energy level combined with steric hindrance effect endow PODPF-TFP with excellent spectra and morphology stability. Finally, organic field-effect transistor (OFET) memory devices are fabricated with PODPF-P/PODPFTFP as the dielectric layers, and they both exhibit flash type storage characteristic. Owing to the electronegativity of fluorine atom, the device based on PODPF-TFP exhibits larger memory window and more stable I _on/I _off ratio during a retention time of 10⁴ s as well as a better aging stability. The present study suggests that fluorinated p-n copolyfluorene electrets could enhance the capabilities of charge trapping and storage, which are promising for OFET memory devices.     

Thermal polymerization of styrene: New data on the conversion dependence of the initiation rate

With the aid of new acceptors of free radicals usable at high temperatures (T > 100°C), the rate of initiation w _i has been measured experimentally for the thermal polymerization of styrene at 122.5°C in a wide range of conversions C = 0–80%. It has been shown that the value of w _i tends to increase in the course of polymerization transformation in agreement with the w _i = f(C) relationship calculated from the kinetic data on the thermal polymerization of styrene in the absence of counters of free radicals. Hypothetical reasons for this non-trivial tendency have been formulated. The experimental dependence w _i = f(C) has been measured for the first time and has been invoked to refine currently available mathematical models for the thermal polymerization of styrene that assume that w _i remains invariable in the course of polymerization transformation.     

Side-chain fluorination on the pyrido[3,4-<Emphasis Type="Italic">b</Emphasis>]pyrazine unit towards efficient photovoltaic polymers

A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination on the polymer properties were explored. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. The results indicated that the introduction of the fluorine atom at meta-positions of phenyl substituted PP unit hardly affected their highest occupied molecular orbital (HOMO) level. More importantly, controlling the degree of side-chain fluorination in the polymers is crucial for optimizing the blend morphology. Three polymers showed different photovoltaic properties. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PT-4fPP:PC₇₁BM (1:1, w:w)/ZrAcac/Al demonstrates a high power conversion efficiency (PCE) of 7.61% under the illumination of AM 1.5G, 100 mW cm^?2, which is the highest value for PP-based PSCs.     

One-Dimensional azido-bridged copper(ii) coordination polymer with schiff base derived from 2-pyridinecarboxaldehyde and taurine: Synthesis and crystal structure

A new copper(II) coordination polymer, [Cu(Pmt)(N₃)] _n (PmtH = N-(2-pyridylmethylidene)taurine), has been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The crystal crystallizes in the monoclinic system, space group P2₁/c, with the cell parameters a = 7.8108(10), b = 18.1233(19), c = 8.2006(10) Å, β = 94.976(6)°, Z = 4, R ₁ = 0.0506, and w R ₂ = 0.1059. The coordination geometry around Cu(II) atom is six-coordinated to two O and four N atoms with a distorted 4+2 octahedron. Two types of rings with sharing Cu apex are alternately created and interconnected to form an interesting 1D zigzag chain propagating along the z axis. Also, the significant weak C-H…N hydrogen bond and π-π stacking interactions between the adjacent chains expanded the 1D structure to a 2D network in the yz plane and stabilize the packing.     

Supramolecular 2D structure of [Co(2-Me-Pyz)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>](NO<Subscript>3</Subscript>)<Subscript>2</Subscript>

The complex [Co(2-Me-Pyz)₂(H₂O)₄](NO₃)₂ is synthesized and its structure is determined. The crystals are monoclinic: space group P2₁/n, a = 10.685(2) Å, b = 6.837(1), c = 12.515(3) Å, β = 91.84(3)°, V = 913.8(3) ų, ρ_calcd = 1.042 g/cm ³, Z = 2. The Co²⁺ ion (in the inversion center) is coordinated at the vertices of the distorted octahedron by two nitrogen atoms of methylpyrazine and four oxygen atoms of the water molecules (Co(1)–N(1) 2.180(3), average Co(1)–O(w) 2.079(3) Å, angles at the Co atom 87.9(1)–92.1(1)°). Supramolecular pseudometallocycles are formed in the structure through the O(w)–H…N(1) hydrogen bonds between the coordinated H₂O molecules and the terminal nitrogen atoms of the 2-methylpyrazine molecules. Their interaction results in the formation of supramolecular layers joined by the NO₃ groups into a three-dimensional framework.     

Structure elucidation and X-ray crystallographic study of 3-(naphth-1-ylmethyl)indole

Synthesis and structure determination of 3-(naphth-1-ylmethyl)indole are reported. The molecular and crystal structures together with the molecular formula were determined by spectral and single crystal X-ray studies. X-ray crystallography revealed the presence of two conformers arising from the flipping of the naphthalene unit. The crystal of the compound belongs to the triclinic crystal system and space group \(P\bar 1\). Crystal data are as follows: a = 10.302(5) Å, b = 12.522(4) Å, c = 13.383(4) Å, α = 111.9(1)°, β = 116.86(6)°, γ = 71.65(5)°; V = 1726.429 ų; Z = 4. The final R and Rw are R = 0.0744 (on observed F′s); R = 0.0924 (all F data), R _w = 0.1757 (observed F ²) and R _w = 0.1834 (all F ² data).     

The Influence of Nonionic Surfactant Adsorption on Enzymatic Hydrolysis of Oil Palm Fruit Bunch

Nonionic surfactants have been utilized to improve the enzymatic hydrolysis of lignocellulosic materials. However, the role of surfactant adsorption affecting enzymatic hydrolysis has not been elaborated well. In this work, nonionic surfactants differing in their molecular structures, namely the polyoxyethylene sorbitan monooleate (Tween 80), the secondary alcohol ethoxylate (Tergitol 15-S-9), and the branched alcohol ethoxylate (Tergitol TMN-6), were studied for their effects on the enzymatic hydrolysis of palm fruit bunch (PFB). The PFB was pretreated with a 10% w/v sodium hydroxide solution and then hydrolyzed using the cellulase enzyme from Trichoderma reesei (ATCC 26921) at 50 °C and pH 5. The optimal conditions providing similar yields of reducing sugar required Tween 80 and Tergitol TMN-6 at 0.25% w/v, while Tergitol 15-S-9 was required at 0.1% w/v. All the surfactants improved the enzymatic conversion efficiency and reduced unproductive binding of the enzyme to lignin. In addition, the adsorption isotherm of cellulase was fit well by the Freundlich isotherm, while adsorption of the three nonionic surfactants agreed well with the Langmuir isotherm. Adsorption capacities of the three nonionic surfactants were consistent with their enhancement efficiencies in hydrolysis. The critical micelle concentration was observed as a key property of nonionic surfactant for adsorption capacity.     

Semicontinuous microemulsion copolymerization of vinyl acetate and butyl acrylate: high solid content and effect of monomer addition rate

Vinyl acetate and butyl acrylate were copolymerized in microemulsion under monomer-starved conditions by a semicontinuous process using different monomer addition rates (R _a). A mixture of sodium dodecyl sulfate and polyethylene glycol dodecyl ether (Brij®35) were used as surfactants. Potassium persulfate was the initiator. High copolymer content latexes (around 40 wt.%), average particle diameters (D _p)?M _w) between 180,000 and 760,000. D _p and M _w of the copolymers decrease as R _a is decreased. As R _a increases, a shoulder in the molar mass distribution was observed at high values of M _w, which was ascribed to chain transfer to polymer. Homogeneous copolymer compositions were observed throughout the reaction, which cannot be obtained by the usual batch process.     

Hydrothermal synthesis and crystal structure of a new 3D Co(II) supramolecule bearing 2-propylimidazole-4,5-dicarboxylate

A new supramolecule [Co(H₂PIDC)₂(H₂O)₂] · 3H₂O (I) (H₂PIDC^? is singly deprotonated 2-propylimidazole-4,5-dicarboxylate) has been synthesized and characterized by the X-ray diffraction method. Compound I crystallizes in the tetragonal space group I4₁/acd with the cell parameters a = 22.1665(14), c = 18.538(2) Å, M _r = 543.35, V = 9108.7(14) ų, ρ _c = 1.585 g/cm³, Z = 16, F(000) = 4528. The Co²⁺ ion is coordinated by two N-O chelated H₂PIDC^? ligands and two water oxygen atoms to form a distorted octahedral geometry. The mononuclear complexes are linked by a hydrogen bond into 1D w-shaped double-chain fragments, which are then linked by oxygen-bifurcated acceptor hydrogen bonds into a 3D framework.     

New complex of manganese(II) with schiff base derived from furaldehyde and diethylenetriamine

A new manganeses(II) complex MnLCl₂ · CH₃OH (L = N,N′-bis(furaldehyde)diethylenetriamine) was synthesized and characterized by X-ray crystallographic analysis. The crystals are orthorhombic, space group Pnma with cell parameters a = 20.998(6), b = 13.314(5), c = 6.785(8) Å, Z = 4, R ₁ = 0.0609, and wR₂ = 0.2116. The coordination geometry around Mn(II) atom is a trigonal-bipyramidic containing one tridenate ligand L and two Cl^? ions.     

Synthesis of water soluble metalloporphyrin-cored amphiphilic star block copolymer photocatalysts for an environmental application

Two series of water-soluble metalloporphyrin-cored amphiphilic star block copolymers were synthesized by controlled radical polymerizations such as atom transfer radical polymerization (ATRP) and reversible addition fragmentation chain transfer (RAFT), which gave eight amphiphilic block copolymer arm chains consisting of poly(n-butyl acrylate-b-poly(ethylene glycol) methyl ether methacylate) (PnBA-b-PEGMEMA, M_n,GPC = 78,000, M_w/M_n = 1.2, 70 wt% of PPEGMEMA) and poly(styrene-b-2-dimethylamino ethyl acrylate) (PS-b-PDMAEA, M_n,GPC = 83,000, M_w/M_n = 1.2, 67 wt% of PDMAEA), yielding porphyrin(Pd)-(PnBA-b-PPEGMEMA)₈ and porphyrin(Pd)-(PS-b-PDMAEA)₈, respectively. Obtained metalloporphyrin polymer photocatalysts were homogeneously solubilized in water to apply to the removal of chlorophenols in water, and was distinguished from conventional water-insoluble small molecular metalloporphyrin photocatalysts. Notably, we found that the water-soluble star block copolymers with hydrophobic–hydrophilic core–shell structures more effectively decomposed the chlorophenol, 2,4,6-trichlorophenol (2,4,6-TCP), in water under visible light irradiation (k = 1.39 h^?1, t_1/2 = 0.5 h) in comparison to the corresponding water-soluble star homopolymer, because the hydrophobic core near the metalloporphyrin effectively captured and decomposed the hydrophobic chlorophenols in water.     

Preparation of Biodiesel with Liquid Synergetic Lipases from Rapeseed Oil Deodorizer Distillate

To reduce industrial production cost, cheap and easily available rapeseed oil deodorizer distillates were used as feedstock to prepare biodiesel in this study. As a result, liquid forms of Candida rugosa lipase and Rhizopus oryzae lipase (ROL) were functioned as new and effective catalysts with biodiesel yield of 92.63% for 30 h and 94.36% for 9 h, respectively. Furthermore, the synergetic effect between the two lipases was employed to enhance biodiesel yield with a result of 98.16% in 6 h under optimized conditions via response surface methodology. The obtained conversion rate surpassed both yields of the individual two lipases and markedly shortened the reaction time. The resultant optimal conditions were ROL ratio 0.84, water content 46 wt% (w/w), reaction temperature 34 °C, and reaction time 6 h.     

Alkoxy substituted benzodithiophene-alt-fluorobenzotriazole copolymer as donor in non-fullerene polymer solar cells

A new benzodithiophene(BDT)-alt-fluorobenzotriazole(FBTA) D-A copolymer J40 was designed and synthesized by introducing 2-octyldodecyloxy side chains on its BDT units, for expanding the family of the BDT- alt-FBTA-based copolymers and investigating the side chain effect on the photovoltaic performance of the polymer in non-fullerene polymer solar cells(PSCs).J40 exhibits complementary absorption spectra and matched electronic energy levels with the n-type organic semiconductor(n-OS)(3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-sindaceno[1,2-b:5,6-b′]dithiophene)(ITIC) acceptor, and was used as polymer donor in the non-fullerene PSCs with ITIC as acceptor. The power conversion efficiency(PCE) of the PSCs based on J40:ITIC(1:1, w/w) with thermal annealing at 120 °C for 10 min reached 6.48% with a higher open-circuit voltage(Voc) of 0.89 V. The high Voc of the PSCs is benefitted from the lower-lying highest occupied molecular orbital(HOMO) energy level of J40. Although the photovoltaic performance of the polymer J40 with alkoxy side chain is lower than that of J60 and J61 with alkylthio-thienyl conjugated side chains, the PCE of6.48% for the J40-based device is still a relatively higher photovoltaic efficiency in the non-fullerene PSCs reported so far. The results indicate that the family of the BDT-alt-FBTA-based D-A copolymers are high performance polymer donor materials for non-fullerene PSCs and the side chain engineering plays an important role in the design of high performance polymer donors in the non-fullerene PSCs.     

Syntheses and characterization of two 1D Cu(II) coordination polymers with 2,2′:6′,2″-terpyridine ligand

The solution reactions of CuCl₂ with 2,2′:6′,2″-terpyridine (Terpy) and dicarboxylic acid (glutaric acid or suberic acid) afforded two 1D coordination polymers [Cu(Terpy)(C₅H₆O₄)] _n (I) and [Cu(Terpy)(C₈H₁₂O₄)] · 3H₂O (II) and their structures were characterized by IR, TG-DTA, and single-crystal X-ray diffraction. Crystallographic data for I: C₂₀H₁₆CuN₃O₄, M _r = 425.90, monoclinic, space group C2/c, a = 10.335(2), b = 21.193(4), c = 8.580(2) Å, β = 111.99(3)°, V = 1742.5(6) ų, Z = 4, ρ _c = 1.623 g/cm³, F(000) = 872, R = 0.0304 and wR = 0.0915; and those for II: C₂₃H₂₉CuN₃O₇, M _r = 523.03, triclinic, space group P \(\bar 1\), a = 8.362(2), b = 10.605(2), c = 14.617(3) Å, α = 73.26(3)°, β = 86.23(3)°, γ = 69.45(3)°, V = 1161.3(4) ų, Z = 2, ρ _c = 1.496 g/cm³, F(000) = 546, R = 0.0636 and wR = 0.1106. X-ray diffracion studies reveal that both complexes I and II feature 1D chain. The 1D polymer chains are connected by π-π-stacking interactions to generate 2D supramolecular layers.     

Water state diagram and thermal properties of fructans powders

The thermal analyses and the water state diagrams of agavin and inulin were investigated. The thermogravimetric analysis and differential scanning calorimetry (DSC) were used to know the difference between fructans. Linear inulin (220.0 °C) showed a higher thermal stability than the branched agavins (206.7 °C). The samples displayed different physical states and lightness depending on the water activity of storage (a _w). The agavin showed different physical states: powder (a _w < 0.33), soft lump (a _w ≈ 0.43), sticky (0.55 < a _w < 0.77), and liquid (a _w > 0.85), while inulin showed two physical states: an amorphous powder at a _w < 0.55 and a semicrystalline solid at a _w > 0.69. These physical states decreased the lightness of fructans. The GAB equation and the Gordon–Taylor equation showed a good fit to the experimental data (R ² > 0.95). The K constant of GAB equation predicted a lower water affinity of inulin powder, while the agavin powder presented a higher water affinity. The DSC showed a glass transition temperature of 118.1 and 135.3 °C for agavin and inulin anhydrous powders, respectively. An increase in water content in agavin showed a higher depression in the glass transition temperature than in inulin. Also, the inulin exhibited a melting point while agavin not. The water state diagrams showed the critical water activity at which the agavin (0.50) and inulin (0.59) powders were stable to physical changes. This knowledge is used to understand the physical and structural behaviors of agavin and inulin at the different water activities.     

A new complex of Mn(II) with highly flexible bistriazole ligand 1,2-bis(1,2,4-triazole-l-yl)ethane: Synthesis and crystal structure

Using a highly flexible ligand 1,2-bis(1,2,4-triazole-1-yl)ethane (L), the one-dimensional (1D) chain polymer [[Mn(L)(Cl)₂(H₂O)₂] _n (I) has been synthesized and structurally characterized. The crystal crystallizes in the monoclinic system, space group C2/c, a = 12.507(4), b = 8.812(3), c = 12.662(4) Å, β = 115.474(6)°, Z = 4. The X-ray analysis shows that I has the three-dimensional (3D) supramolecular network featuring 1D channel along the crystallographic y axis via intermolecular O-H...N interactions.     

Diffusion and phase behavior of a hydroxypropylcellulose-poly(ethylene glycol) system

The solubility and interdiffusion between hydroxypropylcellulose samples of various molecular masses (M _w = 8 × 10⁴, 14 × 10⁴, 37 × 10⁴, 85 × 10⁴, and 115 × 10⁴) and poly(ethylene glycol) (M _w = 400 and 1500) in the range 18–210°C have been studied by optical interferometry and polarization microscopy methods. Oligomeric poly(ethylene glycols) have been considered as solvents for hydroxypropylcellulose. Phase diagrams have been constructed, and Flory-Huggins thermodynamic interaction parameters have been calculated. For the hydroxypropylcellulose-poly(ethylene glycol) 400 system, an LC and crystalline equilibria have been realized. An increase in the M _w of hydroxypropylcellulose to 1500 leads to the appearance of a wide region of amorphous phase segregation with a UCST, whereas the liquidus line is conserved at high concentrations of hydroxypropylcellulose. Such a superposition of two kinds of phase equilibrium that is achieved only with a change in M _w of the oligomeric solvent has been observed for the first time. For all the systems under examination, the kinetics of diffusion mixing has been estimated and the activation energies of the process have been calculated. The concentration dependences of diffusion coefficients demonstrate jumps in the mesomorphic-transition region.     

Polyaniline/montmorillonite nanocomposite thin layers deposited on different substrates

Preparation method of polyaniline/montmorillonite (PANI/MMT) nanocomposite in the form of thin layer deposited on various substrates is optimized in this work to obtain high electrical conductivity. Simple method (i.e. polymerization of anilinium sulfate in the presence of MMT) has been used for the preparation and following four conditions were varied: preparation temperature (T = 10 or 20 °C), preparation time (t = 4 or 6 h), size fraction of MMT (p < 1 or 5 µm), and type of substrate (microscope glass slides, silica glass slides, polyester foils). Therefore, 24 samples were prepared, characterized and their electrical conductivity was compared. Raman spectroscopy and scanning electron microscopy were used for the characterization of the structure of samples. Thickness of layers was measured using atomic force microscopy. Based on the comparison of samples and with respect to the aim of obtaining high electrical conductivity, it was found that the most suitable substrate is polyester foil and preparation conditions are T = 20 °C, t = 6 h, p < 5 µm. To obtain highly conductive layers on glass substrates (although less conductive than layers on foil), preparation time have to be shortened to 4 h.     

Interaction of positional isomers of dimethylbenzene with graphite

The optimized geometries and interaction energies of the intermolecular heterodimers of coronene with o-, m-, and p-dimethylbenzenes (xylenes) calculated by DFT in the PBE0 and B97D functionals were compared. The applicability of coronene as a model for qualitative assessment of the interaction of mononuclear aromatic compounds with the graphite surface was demonstrated. The necessity of including long-range dispersion interactions in DFT calculations of the dimerization energies of aromatic systems was shown. The sorption enthalpies of p- and m-xylenes were shown to be almost equal irrespective of the conditions of the chromatographic experiment. The preferred sorption of p- over m-xylene on graphite is solely due to the entropy factor.     

Theoretical and experimental study of molecular structure and vibrational spectra of <Emphasis Type="Italic">N</Emphasis>-(2-pyridylmethyl)-2-pyrazinecarboxamide

N-(2-Pyridylmethyl)-2-pyrazinecarboxamide was prepared and its crystal structure was investigated by X-ray analysis. The compound crystallizes in the triclinic space group \(P{\bar 1}\) with a = 4.262(3), b = 12.117(9), c = 20.840(18) Å, α = 91.802(6), β = 89.834(7), γ = 91.845(6)°, V = 1075.2(16) ų, Z = 4, and D = 1.323?Mg/m³. The structure was solved by direct method and refined to R = 0.0699 and wR ₂ = 0.1268 by full matrix anisotropic least-squares method. Using the Hartree-Fock and density functional method (B3LYP) with 6-31G(d) basis set, the molecular geometry and vibrational frequencies of the title compound has been investigated and compared with experimental ones from experimental studies. The optimized bond lengths obtained by RHF method and bond angles obtained by B3LYP method show better agreement with the experimental values. The vibrations computed of the title compound by the RHF and DFT methods are in good agreement with the observed IR spectra data.