Tetra-EDOT substituted 3D electrochromic polymers with lower band gaps

A couple of novel electrochromic materials poly(2,3,4,5-tetrakis(2,3-hydrothieno[3,4-b]dixin-5-yl)-1-methyl-1H-pyrrole)(P(t-EDOT-mPy))and poly(5,5',5",5'"-(thiophene-2,3,4,5-tetrayl)tetrakis(2,3-dihydrothieno[3,4-b][1,4]dioxine))(P(t-EDOTTh))are electrodeposited via multi-position polymerization of their tetra-EDOT substituted monomers t-EDOT-mPy and t-EDOT-Th,respectively.Compared with the linear 2D structured poly(thiophene)(E_g=2.2 eV)and poly(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophene)(E_g=1.7eV),P(t-EDOT-Th)(E_g=1.62eV)has the lowest band gap.Hence,we speculate that the band gaps of the two polymers,having 3D structures,are decreased in contrast to non-substituted polymers or bi-EDOT substituted polymers,thiophene and 1-methyl-1H-pyrrole.The results indicated that P(t-EDOT-Th)thin films are more stable and show higher transmittance amid two polymers,which may find their utilization in organic optoelectronics.     

All-polymer solar cells with perylenediimide polymer acceptors

Four polymers based on perylenediimide co-polymerized with thiophene, bithiophene, selenophone and thieno[3,2-b]thiophene were investigated as the acceptor materials in all-polymer solar cells. Two different donor polymers, poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b′]dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene)-2-carboxylate-2,6-diyl](PTB7-Th) and poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3′′′-di(2-dodecyltetradecyl)-2,2′;5′,2″;5″,2′′′-quaterthiophen-5,5′′′-diyl)](Pff BT4T-2DT), with suitably complementary absorption spectra and energy levels were applied and examined. Among all different donor-acceptor pairs studied here, the combination of PTB7-Th:poly[N,N′-bis(1-hexylheptyl)-3,4,9,10-perylenediimide-1,6/1,7-diyl-alt-2,5-thiophene](PDI-Th) exhibited the best power conversion efficiency(PCE) of 5.13%, with open-circuit voltage(V_(oc)) = 0.79 V, short-circuit current density(J_(sc)) = 12.35 mA·cm~(-2) and fill-factor(FF) = 0.52. The polymer of PDI-Th acceptor used here had a regio-irregular backbone, conveniently prepared from a mixture of 1,6- and 1,7-dibromo-PDI. It is also noteworthy that neither additive nor posttreatment is required for obtaining such a cell performance.     

Bis[1,3]thiazolo[4,5-<Emphasis Type="Italic">f</Emphasis>:5',4'-<Emphasis Type="Italic">h</Emphasis>]thieno[3,4-<Emphasis Type="Italic">b</Emphasis>]quinoxaline Derivatives as New Building Blocks of Polymers for Organic Electronics

New derivatives of bis[1,3]thiazolo[4,5-f:5',4'-h]thieno[3,4-b]quinoxaline containing the fused thiadiazoloquinoxaline moiety have been prepared. Monomer M1 shows strong light absorption within 600–800 nm due to intramolecular charge transfer. The optical bandgap E _g ^opt determined from the absorption edge in a film is 1.44 eV. The HOMO and LUMO levels are–5.44 and–3.12 eV, respectively. The new structural fragment has a rather low frontier molecular orbital energies and a small bandgap; therefore, it is a promising building block for the synthesis of polymers for organic electronics.     

New monomer based on thienopyrazine with fluorocarbazole substituents as a promising building block for organic electronics

A new monomer, 2,3-bis[6-fluoro-9-(2-octyldodecyl)-9H-carbazol-3-yl]-3,3'-[5,7-di(5-bromothienyl-2)thieno[3,4-b]pyrazine, M1, based on thienopyrazine containing fluorocarbazole substituents in the pyrazine ring has been synthesized. The structure of the compound has been proved by ¹H and ¹³C NMR and elemental analysis. The HOMO and LUMO energies for monomer M1 and its precursor 3 determined by the electrochemical method are–5.03 and–3.31 eV, as well as–5.28 and–3.36 eV, respectively. Band gap widths E _g ^ec are 1.72 and 1.92 eV for compounds M1 and 3, respectively. The new structural fragment has rather deep energy levels of frontier molecular orbitals and a small band gap width; therefore, it is a promising building block for the synthesis of polymers for organic electronics.     

Synthesis and characterization of <Emphasis Type="Italic">D</Emphasis>-/<Emphasis Type="Italic">L</Emphasis>-methionine grafted PEDOTs for selective recognition of 3,4-dihydroxyphenylalanine enantiomers

Two pairs of amino-acid functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives, namely, poly(N-(tert-butoxycarbonyl)-L-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (L-PEDOT-Boc-Met) and poly(N-(tert-butoxycarbonyl)-D-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (D-PEDOT-Boc-Met); poly(L-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (L-PEDOT-Met) and poly(D-methionyl (3,4-ethylenedioxythiophene-2’-yl)methylamide) (D-PEDOT-Met) were synthesized via chemical oxidative polymerization of corresponding monomers. The structural characterization, spectroscopic properties and thermal stability of these monomers and polymers were systematically explored by FTIR spectra, Raman spectra, XRD spectra, UV-Vis spectra and thermogravimetric analysis. As chiral electrode materials, these polymers were employed to successfully recognize 3,4-dihydroxyphenylalanine (DOPA) enantiomers by cyclic voltammetry (CV) in sulphuric acid solution. The measurement results reveal that the tendency was hetero-chiral interaction between L-PEDOT-Met/PVA/GCE and D-DOPA, D-PEDOT-Met/PVA/GCE and L-DOPA, respectively. Also, the mechanism of chiral discrimination was discussed. All the results implied that the combination of electrochemical molecular recognition technology and chiral PEDOT materials can be a promising approach for chiral recognition and may open new opportunities for facile, biocompatible, sensitive and robust chiral assays in biochemical applications.     

Molecular mechanism of propane oxidative dehydrogenation on surface oxygen radical sites of VO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>/TiO<Subscript>2</Subscript> catalysts

Minimum energy pathways of propane oxidative dehydrogenation to propene and propanol on supported vanadium oxide catalyst VO _x /TiO₂ were studied by periodic discrete Fourier transform (DFT) using a surface oxygen radical as the active site. The propene formation pathway was shown to consist of two consecutive hydrogen abstraction steps. The first step includes C_β–H bond activation of propane followed by the formation of a surface hydroxyl group V–O _t H and a propyl radical n-C₃H₇. This step with the activation energy E* = 0.56 eV (54.1 kJ/mol) appears to be rate-determining. The second step involves the reaction of the bridging O _b oxygen atom with the methylene C–H bond of propyl radical n-C₃H₇ followed by the formation of a hydroxylated surface site HO _t –V⁴⁺–O _b H and propene. The initial steps of the C–H bond activation during propane conversion to propanol and propene by ODH on V⁵⁺–(O _t O _b )^? active sites are identical. The obtained results demonstrate that participation of surface oxygen radicals as the active sites of propane ODH makes it possible to explain relatively low activation energies observed for this reaction on the most active catalysts. The presence of very active radical species in low concentration seems to be the key factor for obtaining high selectivity.     

Rh<Subscript>2</Subscript>(OAc)<Subscript>4</Subscript>-catalyzed reaction of 2-(2-carbonylvinyl)-3-phenyl-2<Emphasis Type="Italic">H</Emphasis>-azirines with diazo esters

Rh₂(OAc)₄-catalyzed reaction of 2-(2-carbonylvinyl)-3-phenyl-2H-azirines with diazo esters proceeds through an intermediate generation of azirinium ylide suffering a nonstereoselective ring opening to form (3Z)- and (3E)-2-azahexa-1,3,5-trienes. The former depending on configuration of the C ⁵ =C ⁶ bond may undergo cyclization either in derivative of 2,3-dihydropyridine, or in pyrrolium ylide that isomerizes into a derivative of 1H-pyrrole. According to DFT calculation, the preferred formation of pyrroles at increasing volume of Z-substituent at the atom C ⁶ and of substituents at the atom C ¹ of 2-azahexatriene occurs due to the destabilization of more sterically loaded transition states of 1,6-cyclization.     

New donor–acceptor copolymers with ultra-narrow band gap for photovoltaic application

Two novel donor–acceptor (D–A) copolymers P1 and P2 with the thiazoloquinoxaline repeating acceptor moiety and different donor moieties of benzo[1,2-b:4,5-b']dithiophene and isomeric benzo[2,1-b:3,4-b']dithiophene have been prepared. The polymers show light absorption at 300–1200 nm and a band gap width of 0.98 and 1.14 eV, respectively. The energies of the HOMO (–5.42 and–5.29 eV) and LUMO (–3.90 and–3.83 eV) levels of polymers P1 and P2 have been determined. The absorption maximum for polymer P1 in the long-wavelength region is red-shifted by 161 nm, which is caused by stronger charge transfer in P1 as compared with P2. This fact indicates that the benzo[1,2-b:4,5-b']dithiophene structural moiety has a higher electron-donating ability than the benzo[2,1-b:3,4-b']dithiophene moiety. The red shift of the absorption spectrum of polymer P1 in comparison with that of P2 indicates that interchain π–π stacking interactions are more efficient in P1 than in P2.     

Secondary self-assembly behaviors of PEO-<Emphasis Type="Italic">b</Emphasis>-P<Emphasis Type="Italic">t</Emphasis>BA-<Emphasis Type="Italic">b</Emphasis>-PS triblock terpolymers in solution

A series of PEO₄₅-b-PtBA₅₃-b-PS _x (x = 42, 84, 165) triblock terpolymers were synthesized by the atom transfer radical polymerization and characterized by size exclusion chromatography and ¹H NMR. Their self-assemblies were conducted by a two-step hierarchical self-assembly method and a one-step dialysis method and the self-assembly behaviors were investigated. The morphologies, sizes, and size distributions of micelles produced by the self-assembly were determined by transmission electron microscopy and dynamic light scattering. The secondary self-assembled structure of PEO₄₅-b-PtBA₅₃-b-PS _x obtained by the two-step hierarchical self-assembly could be controlled by tuning the length of PS block, the core forming block. The micelles were uniform with diameters of 20–25 nm and their size distributions, except for that of PEO₄₅-b-PtBA₅₃-b-PS₁₆₅, were narrow with particle size distribution indexes ranging from 0.014 to 0.246. The one-step dialysis of the triblock terpolymers produced vesicular micelles with distinct vesicle walls that exhibited similar thicknesses. The vesicles did not show significant aggregation. The size distribution of PEO₄₅-b-PtBA₅₃-b-PS₄₂ vesicle was the narrowest with a particle size distribution index value of 0.135. The PEO₄₅-b-PtBA₅₃-b-PS₁₆₅ vesicles tended to overlap with each other.     

New Polymer Syntheses Part 60: A Facile Synthetic Route to Polyamides Based on Thieno[2,3-<Emphasis Type="Italic">b</Emphasis>]thiophene and Their Corrosion Inhibition Behavior

Polyamides containing thieno[2,3-b]thiophene moiety were prepared via a simple polycondensation reaction of the diaminothieno[2,3-b]thiophene monomer 1a with different kinds of diacid chlorides (including oxalyl, adipoyl, sebacoyl, isophthaloyl, terephthaloyl, 4,4′-azodibenzoyl, 3,3′-azodibenzoyl, p-phenylene diacryloyl) in the presence of LiCl and NMP as a solvent through lowtemperature solution polycondensation. The chemical structures of model compound and synthesized polyamides were confirmed by FTIR, nuclear magnetic resonance spectroscopy (including ¹H-NMR and ¹³C-NMR) and elemental analysis. In addition, the thermal stability, crystallinity structure and surface morphology of synthesized polyamides were characterized via thermogravametric analysis (TGA), wide-angle X-ray diffraction analysis (WAXD) and scanning electron microscopy (SEM). Also, the corrosion inhibition behavior of selected examples of polyamides was investigated; the inhibitive effect of the investigated polymers for carbon steel in 1.0 mol·L^?1 HCl was studied using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods. PDP results displayed that the polyamides containing thieno[2,3-b]thiophene moiety can be as mixed-type inhibitors. The inhibition efficiency (P, %) was found to be in the range from 67.13% to 96.01%. There is an increase in P by the synthesized polymers in comparison to the starting monomer. The adsorption of these polymers was found to obey Langmuir adsorption isotherm.     

Synthesis of 1-(1,3-dialkyl-2-oxo-2,3-dihydro-1<Emphasis Type="Italic">H</Emphasis>-imidazo-[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-5-yl)-5-oxopyrrolidine-3-carboxylic acids

Nitration of 2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-one gave its 5-nitro derivative which was subjected to alkylation with dimethyl sulfate, diethyl sulfate, and benzyl(dimethyl)phenylammonium chloride. The resulting 1,3-dimethyl-, 1,3-diethyl-, and 1,3-dibenzyl-5-nitro-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones were reduced to the corresponding 1,3-dialkyl-5-amino-2,3-dihydro-1H-imidazo[4,5-b]pyridin-2-ones, and the latter reacted with itaconic acid to produce 1-(1,3-dialkyl-2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-5-yl)-5-oxopyrrolidine-3-carboxylic acids. 1-(2-Oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-5-yl)-5-oxopyrrolidine-3-carboxylic acid was obtained by analogous reaction with 5-amino-2,3-dihydro-1H-imidazo[4,5-b]-pyridin-2-one.     

Synthesis and X-ray study of 6<Emphasis Type="Italic">H</Emphasis>-chromeno[3,4-<Emphasis Type="Italic">e</Emphasis>][1,3,4]triazolo[2,3-<Emphasis Type="Italic">a</Emphasis>]pyrimidine

2-Dimethylamino methylenechromanone 1 reacted with 4H-1,2,4-triazol-3-amine in acetic acid to give only one isolated product which was identified by X-ray study as 6H-chromeno[3,4-e][1,3,4]triazolo[2,3-a]-pyrimidine. The molecular structure of 3, C₁₂H₈N₄O, was determined to be monoclinic, P2₁/c, a = 16.3875(5), b = 8.8378(3), c = 13.8392(5) Å, β = 101.190(1)°, V = 1966.22(11) ų, Z = 8.     

Transition metal-free synthesis of quinolino[2′,3′:3,4]pyrazolo[5,1-<Emphasis Type="Italic">b</Emphasis>]quinazolin-8(6<Emphasis Type="Italic">H</Emphasis>)-ones via cascade dehydrogenation and intramolecular <Emphasis Type="Italic">N</Emphasis>-arylation

2-(2-Chloroquinolin-3-yl)-3-(arylamino)-2,3-dihydroquinazolin-4(1H)-one was converted to quinolino[2′,3′:3,4]pyrazolo[5,1-b]quinazolin-8(6H)-ones in the presence of KOtBu in DMSO at room temperature. The present method has the advantages of easy conditions, construction of highly novel five heterocycles, transition metal-free conditions, cascade dehydrogenation and intramolecular N-arylation and good to high yield of products.     

Oxidation of the polycrystalline gold foil surface and XPS study of oxygen states in oxide layers

Gold oxide films obtained on the surface of polycrystalline gold foil upon oxidation by oxygen activated by a high-frequency discharge have been studied by X-ray photoelectron spectroscopy. High-frequency O₂ activation affords oxide films more than 3–5 nm thick. As follows from Au4f spectra, the surface gold atoms are oxidized to the oxidation state +3. The O1s spectra have a composite shape and are decomposed into four components that characterize nonequivalent states of oxygen in the resulting oxide films. It is assumed that the two major oxygen states (E _b(O1s) = 529.0 and 530.0 eV) correspond to the oxygen atoms in two-and three-dimensional gold oxide Au₂O₃, respectively. The oxygen states characterized by the higher binding energies (E _b(O1s) = 531.8 and 535.2 eV) likely correspond to molecular oxygen in peroxide and superoxide groups, respectively.     

Regioselectivity in the reactions of <Emphasis Type="Italic">N</Emphasis>-(polychloroethylidene)-sulfonamides with 1<Emphasis Type="Italic">H</Emphasis>-pyrrole and 1-methyl-1<Emphasis Type="Italic">H</Emphasis>-pyrrole

N-(2,2,2-Trichloroethylidene)arenesulfonamides react with 1H-pyrrole and 1-methyl-1H-pyrrole to give the corresponding N-[2,2,2-trichloro-1-(1H-pyrrol-2-yl)ethyl]arenesulfonamides. The reaction of N-(2,2,2-trichloroethylidene)trifluoromethanesulfonamide with pyrrole leads to a mixture of 2-mono-and 2,5-disubstituted pyrroles, whereas in the reaction with 1-methyl-1H-pyrrole only the 2-substituted compound is formed. N-(2,2-Dichloro-2-phenylethylidene)-4-methylbenzenesulfonamide reacts with 1H-pyrrole to form N-[2,2-dichloro-2-phenyl-1-(1H-pyrrol-2-yl)ethyl]-4-methylbenzenesulfonamide, and its reaction with 1-methyl-1H-pyrrole gives a mixture of 2-and 3-monosubstituted derivatives. The results of quantum-chemical calculations of the initial reactants and products indicate that the process is orbital-controlled. A good agreement is observed between the experimental data and theoretical conclusions concerning the dependence of the reaction regioselectivity on the nature of substituents in the electrophile molecule.     

Alkenyl derivatives of 5-nitro-2-pyridone: Synthesis and halocyclization

Alkylation of 5-nitro-2-pyridone by alkenyl halides in acetone in the presence of K₂СО₃ proceeds with generation of a mixture of N- and О-derivatives with N-isomer prevailing. 1-Allyl- and 1-methylallyl-5-nitro-2-pyridone react with halogens with the formation of 2-halomethyl-6-nitro-2,3-dihydrooxazolo[3,2-a]-pyridinium halides. 1-Prenyl-5-nitro-2-pyridone reacts with bromine with the formation of 3-bromine-2,2-dimethyl-7-nitro-3,4-dihydro-2Н-pyrido[2,1-b][1,3]oxazinium bromide, and with iodine giving 2,2-dimethyl-7-nitro-3,4-dihydro-2Н-pyrido[2,1-b][1,3]oxazinium triiodide.     

Synthesis and crystal structure of two complexes [Cu<Subscript>2</Subscript>(NiL)<Subscript>2</Subscript>Cl<Subscript>4</Subscript>] and [Cd<Subscript>2</Subscript>(CuL)<Subscript>2</Subscript>Cl<Subscript>4</Subscript>]

Macrocyclic and supermolecular complexes [Cu₂(NiL)₂Cl₄] (I) and [Cd₂(CuL)₂Cl₄] (II) (H₂L = 2,3-dioxo-5,6,14,15-dibenzo-1,4,8,12-tetraazacyclo-pentadeca-7,13-diene) have been synthesized and structurally determined by X-ray diffraction and IR spectrum. Complex I crystallizes in the monoclinic system with P2₁/n group, a = 10.9019(15), b = 14.3589(19), c = 12.4748(17) 0A, β = 108.645(2)°, Z = 4. Complex II crystallizes in the monoclinic system with P2₁/n group, a = 10.9784(16), b = 14.580(2), c = 12.8904(18) Å, β = 109.339(2)°, Z = 4.     

WO<Subscript>3</Subscript> films prepared by thermal oxidation of magnetron-sputtered tungsten: Synthesis and properties

X-ray powder diffraction shows that a monoclinic WO_2.90 film is formed during the thermal oxidation of 200-nm-thick magnetron-sputtered metallic tungsten on quartz substrates at T = 793 K. Temperature elevation to T = 840 K yields orthorhombic WO₃ with preferred (001) orientation. Adsorption spectroscopy shows that these films have high transparency (～90%) in the wavelength range 450–900 nm, and interference is observed in the transparency range. Two types of transitions are discovered: indirect transitions with the energies E _gi = 2.77 and 2.41 eV and direct transitions with the energies E _gd = 5.49 and 4.82 eV for the oxide films formed at 793 and 840 K, respectively. The tendency toward the increase in the transition energy with increasing annealing temperature proves that the crystallinity and order of the film improve.     

Convenient regioselective reaction in presence of H<Subscript>3</Subscript>PW<Subscript>12</Subscript>O<Subscript>40</Subscript>: synthesis and characterization of pyrazolo[3,4-<Emphasis Type="Italic">b</Emphasis>]quinoline-3,5-diones

We describe regioselective synthesis of pyrazolo[3,4-b]quinoline derivatives by multicomponent reaction of dimedone, 5-aminopyrazolone, and aromatic aldehydes in presence of H₃PW₁₂O₄₀ as catalyst. When this multicomponent reaction was investigated without catalyst under reflux conditions, a mixture of products was obtained, while the reaction successfully proceeded to formation of pyrazolo[3,4-b]quinoline in presence of H₃PW₁₂O₄₀. Good product yield, short experimental time, and low-cost catalyst provide convenient synthesis for formation of pyrazolo[3,4-b]quinoline pharmacological compounds.     

Reactions of 2,3-dioxopyrrolo[2,1-<Emphasis Type="Italic">a</Emphasis>]isoquinolinecarboxylic acid esters and amides with nitrogen-centered nucleophiles

Reactions of ethyl 2,3-dioxopyrrolo[2,1-a]isoquinoline-1-carboxylates with active nitrogen-centered nucleophiles (phenylhydrazine, hydroxylamine, and benzylamine) involve opening of the pyrrole ring with formation of 2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-N′¹,N′⁴-diphenyl-3-(2-phenylhydrazono) succinohydrazide, 5-(6,7-dimethoxy-3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-2,3,4,5-tetrahydro-1H-1,2-oxazine-3,4,6-trione, and ethyl 4-benzylamino-2-(3,3-dimethyl-1,2,3,4-tetrahydroisoquinolin-1-ylidene)-3,4-dioxobutanoate, respectively. Cyclic amides derived from 5,5-dimethyl-2,3-dioxo-2,3,5,6-tetrahydropyrrolo[2,1-a]isoquinoline-1-carboxylic acid react with benzylamine in a similar way. Reactions of the title compounds with weaker nucleophiles, such as semicarbazide and thiosemicarbazide, are not accompanied by opening of the pyrrole ring, and the products are the corresponding semicarbazones and thiosemicarbazones at the C²=O carbonyl group.