Hydroaminoalkylation/Buchwald-Hartwig amination sequences for the synthesis of benzo-annulated seven-membered nitrogen heterocycles

Reaction sequences consisting of an initial intermolecular titanium-catalyzed hydroaminoalkylation of a suitably ortho-bromophenyl-substituted alkene and a subsequent intramolecular Buchwald-Hartwig amination are used for the synthesis of benzazepine, benzoxazepine, and benzothiazepine derivatives. While in the latter two cases, the hydroaminoalkylation products obtained from an allyl (2-bromophenyl) ether or an allyl (2-bromophenyl) thioether must be purified prior to the subsequent palladium-catalyzed amination step, both reactions can be combined to an efficient one-pot procedure for the synthesis of 2,3,4,5-tetrahydrobenzo[b]azepines when 4-(2-bromophenyl)-1-butene and various N-methylanilines are used as the starting materials.     

Synthesis and heterocyclization of 2-{[2-(4-bromophenyl)-2-oxoethyl]sulfanyl}pyrimidin-4(3<Emphasis Type="Italic">h</Emphasis>)-ones

Alkylation of sodium 4(5)-alkyl-6-oxo-1,6-dihydropyrimidine-2-thiolates with 2-bromo-1-(4-bromophenyl)ethan-1-one afforded 2-{[2-(4-bromophenyl)-2-oxoethyl]sulfanyl}pyrimidin-4(3H)-ones. Analogous reaction with sodium 4-trifluoromethyl-6-oxo-1,6-dihydropyrimidine-2-thiolate gave a mixture of 2-{[2-(4-bromophenyl)-2-oxoethyl]sulfanyl}-4-(trifluoromethyl)pyrimidin-4(3H)-one and its intramolecular cyclization product, 3-(4-bromophenyl)-3-hydroxy-7-trifluoromethyl-2,3-dihydro[1,3]thiazolo[3,2-a]-pyrimidin-5-one.     

Synthetic protocols and building blocks for molecular electronics

Simple and readily accessible aryl bromides are useful building blocks for thiol end-capped molecular wires. Thus, 4-bromophenyl tert-butyl sulfide and 1-bromo-4-(methoxymethyl)benzene serve as precursors for a variety of oligo(phenylenevinylene) and oligo(phenyleneethynylene) wires via efficient synthetic transformations as presented in this paper.     

Synthesis of a Novel Low‐Bandgap Polymer Based on a Ladder‐Type Heptacyclic Arene Consisting of Outer Thieno[3,2‐b]thiophene Units for Efficient Photovoltaic Application

A novel conjugated polymer PIDTT‐quinoxaline (Qx) based on the coplanar thieno[3,2‐b]thiophene‐phenylene‐thieno[3,2‐b]thiophene structure is synthesized and evaluated as an electron‐donor material for bulk‐heterojunction polymer solar cells (BHJ PSCs). The absorption spectra, electrochemical, charge transport, and film morphology properties as well as theoretical modeling of PIDTT‐Qx are investigated to understand its intrinsic structure–property relationship. As expected, this polymer with an extended π‐conjugated backbone exhibits a narrow‐bandgap and board absorption spectrum for enhanced light harvesting. BHJ PSCs (ITO/PEDOT:PSS/polymer:PC₇₁BM/interlayer/Al) afford a maximum power conversion efficiency of 5.05% with an open‐circuit voltage of 0.84 V, a short‐circuit current density of 11.26 mA cm⁻², and a fill factor of 53.4%. These results demonstrate the potential of PIDTT‐Qx as an efficient electron‐donor material for BHJ PSCs.

     

Voltammetric and electrochemical ESR studies of oxidation reactions mediated by tris(4-bromophenyl)amine in acetonitrile

The electrochemical oxidation of tris(4-bromophenyl)amine in the presence of 2,6-lutidine is examined in acetonitrile. Voltammetric and spectroscopic investigations suggest that the electrogenerated triaryl aminium radical cation oxidizes 2,6-lutidine in an EC' mechanism, and an equilibrium constant for this homogeneous electron transfer is estimated. The mediated oxidation of a protected phenyl selenoglycoside by this reaction mixture is studied by the use of electrochemical ESR, employing a tubular flow cell, and signal intensity data is found to be consistent with the proposed mechanism, allowing the determination of kinetic parameters by computational simulation. Products of the mediated glycoside oxidation are determined by proton NMR and mass spectrometry.     

Microwave-assisted synthesis of new substituted anilides of quinaldic acid

In this study a one step method for the preparation of substituted anilides of quinoline-2-carboxylic acid was developed. This efficient innovative approach is based on the direct reaction of an acid or ester with substituted anilines using microwave irradiation. The optimized method was used for the synthesis of a series of eighteen substituted quinoline-2-carboxanilides. The molecular structure of N-(4-bromophenyl)quinoline-2-carboxamide as a model compound was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group with four molecules within the unit cell and the total structure of the compound can be described as "a slightly screwed boat".     

Binary Blends of Polymer Semiconductors: Nanocrystalline Morphology Retards Energy Transfer and Facilitates Efficient White Electroluminescence

Summary: Blends of poly(9,9‐dioctylfluorene) (PFO) and poly(2‐methoxy‐5(2′‐ethyl‐hexyloxy)‐1,4‐phenylenevinylene) (MEH‐PPV) were found to phase separate into 40–50 nm crystalline PFO domains and to exhibit efficient white electroluminescence when the composition is below 30 wt.‐% MEH‐PPV. The 5 wt.‐% nanocrystalline blends had a luminance of 4 000 cd · m⁻², an external quantum efficiency of 3.1%, and a current efficiency of 3.7 cd · A⁻¹. Transmission electron microscopy, electron diffraction, and atomic force microscopy of blends with higher MEH‐PPV content and the two homopolymers showed them to be amorphous. Only orange‐red electroluminescence, characteristic of MEH‐PPV, was observed from the amorphous blends due to efficient energy transfer from PFO. These results demonstrate that energy transfer processes in binary PFO:MEH‐PPV blends and light‐emitting devices based on them can be controlled through the morphology and composition.

TEM image of a PFO:MEH‐PPV blend.     

Conjugated Random Terpolymer Donors towards High‐Efficiency Polymer Solar Cells

Over the past decades, polymer solar cells (PSCs) which contain conjugated polymers as electron donor and/or acceptor materials in active layers have achieved the power conversion efficiency (PCE) over 17%. Among them, tremendous alternative donor‐acceptor (D‐A) type conjugated copolymers have been reported as donor materials. Nevertheless, plenty of rooms still exist to further improve the photovoltaic performance for practical applications. Besides the exploration of the increasingly challenging novel D and/or A monomers to construct new D‐A copolymer donors, conjugated random terpolymer donors which involve a third existing monomer (D or A) provide an extra simple promising strategy to promote the photovoltaic performance to a higher level. Herein, recent progress on random terpolymer donors for efficient PSCs was reviewed. Firstly, random terpolymer donors were classified by several typical molecular building blocks. Then, the influences of the third monomer on various random terpolymers were highlighted according to the enhancement of light‐harvesting ability, modification of energy levels and optimization of the bulk‐heterojunction (BHJ) morphology. Finally, several issues which might be concerned in future research on random terpolymer donors were proposed. This review may be helpful for providing guidelines to design efficient random terpolymer donors as well as better‐understanding of the structure‐property‐performance correlations towards high performance PSCs via random terpolymer approach.     

Synthesis of tripod-shaped oligo(phenylene)s with multiple ethenyl groups at the bases for chemisorption on hydrogen-terminated silicon surfaces

This communication describes an efficient and convergent synthesis of monodisperse, nanometer-sized, and tripod-shaped oligo(phenylene)s with a triallylsilyl group at the base of each leg and a chlorophenyl group at the focal point of the tripod. These molecules were designed as model compounds for the study of chemisorption of rigid molecules containing multiple ethenyl groups on hydrogen-terminated silicon surfaces. The compounds were synthesized from p-chlorophenyl-tris(p-bromophenyl)silane via selective Pd-catalyzed Ishiyama-Miyaura reaction with bis(pinacolato)diboron, followed by Suzuki coupling with aryl dihalides to elongate the legs. The legs were then end-capped with triallylsilyl groups through Suzuki coupling with 4-triallyphenylboronic acid.     

Cytotoxicity evaluation of coumarin derivatives containing 4-bromophenyl or anthracene moieties

The cytotoxic properties of four synthesized coumarin derivatives containing 4-bromophenyl or anthracene moieties against the human hepatocellular carcinoma cell lines (HepG-2) were investigated in vitro by use of the sulforhodamine B (SRB) assay. The four coumarin derivatives are 3-(4-bromophenyl)-benzo[5,6]coumarin (1a), 3-(4-bromophenyl)-7-(N,N-diethylamino)coumarin (1b), 3-(4-(anthracen-10-yl)phenyl)-benzo[5,6]coumarin (2a), and 3-(4-(anthracen-10-yl)phenyl)-7-(N,N-diethylamino)coumarin (2b). The preliminary results indicate that 1a, 2a, and 2b have significant cytotoxicity against HepG-2 whereas 1b has a growth-promotion effect.     

Synthesis and characterization of green-emitting phosphorescent Ir(III) complexes based on phenyl benzimidazole ligand

Several new Ir(III) complexes with 2-(4-bromophenyl)-1H-benzo[d]imidazole or 2-(4-bromophenyl)- 1-methyl-benzo[d]imidazole ligands as cylcometalated ligand and acetylacetonate or picolinate as the ancillary ligand were synthesized and their structures and photophysical properties were characterized. HOMO and LUMO energy levels and the molecular structures of Ir(III) complexes were scrutinized by DFT calculations. The complexes exhibited green luminescence at the maximum emission peaks at ca 495–522 nm. The methyl group substituent and replacing of acetylacetonate with picolinate complex can enhance the complex thermal stability. HOMO energy levels of the complexes vary from –4.99 to –5.44 eV, the LUMO energy levels are between –1.52 and –1.97 eV.     

芳基噻唑联哌啶酰胺类化合物的合成及生物活性

为了寻找具有生物活性的新型芳香基噻唑联哌啶酰胺类先导化合物,设计并合成了15个未见文献报道的芳基噻唑联哌啶酰胺类化合物,其结构经1HNMR、13CNMR和HRMS确证,生物活性测定结果显示,部分目标化合物表现出高效的抑菌和杀虫活性,如在200μg/mL浓度下,5-(3-溴苯基)-4-甲基-2-(1-((4-硝基苯基)磺酰基)哌啶-4-基)噻唑(6b)对黄瓜霜霉病的抑菌活性为100%,优于嘧菌酯,5-(4-溴苯基)-2-(1-((4-氯苯基)磺酰基)哌啶-4-基)-4-甲基噻唑(6c)对水稻纹枯病的抑菌活性为58.86%,与嘧菌酯相当;在500μg/m L浓度下,(4-(5-(3-溴苯基)-4-甲基噻唑-2-基)哌啶-1-基)(间甲基苯基)酮(6h)对粘虫的杀虫活性为100%.     

Free-energy correlation for catalysis of outer sphere electron-transfer reactions by noncoordinated pyridine derivatives

Recent experimental data concerning the rate constants and their free energy of the outer sphere electron-transfer reactions, as catalyzed by noncoordinated pyridine derivatives in aqueous solution, are examined for possible correlation. For the electron transfer reactions between V or Eu and the bipyridyl derivatives, such as N,N'-dimethyl-4,4′-bipyridyl (paraquat) or diquat, the data are correlated quite well by the Marcus equation. The electron exchange rate constant, 5 × 10⁷M^?1·s^?1, for an organic radical ion and its parent molecule obtained from semiquinones or their related compounds can be applied to these pyridine derivatives. However, in some cases such as electron transfer from paraquat or diquat cation radical to Co(en), positive departures from the Marcus model are observed. These positive departures are interpreted in terms of interaction between the molecular orbitals of electron donors and electron acceptors in the transition state.     

Design,synthesis and antimicrobial activities of 1,2,3-triazole derivatives

Fifteen 1-(4-substituted phenyl)-4-(4-bromophenyl)-5-(halo-o-hydroxyphenyl)imino-1,2,3-triazoles were designed and synthesized based on rational combination of 1,2,3-triazoles and(halo)o-hydroxyphenyl group according to the superposition principle of reinforcement of biological activities.All the compounds were tested to an in vitro antimicrobial screening against M.a.and E.c..Compounds IIe-IIo exhibited more potent antimicrobial activities against M.a.and E.c.than triclosan and fluconazole,which provided valuable information to further study of novel antimicrobial research.     

Di(micro-oxo) binuclear manganese(III,IV) poly(bipyridyl) complexes bearing four ruthenium(II) photoactive units: synthesis, characterization, and photoinduced electron-transfer properties

In order to model the photoinduced electron-transfer reactions from the manganese cluster to the photoactive P680 chlorophylls in photosystem II, three heterohexanuclear complexes, [Mn2III,IVO2[RuII(bpy)2(Ln)]4]11+ [bpy = 2,2'-bipyridine, n = 2 (1a), 4 (1b), 6 (1c)], in which one MnIII,IV(micro-O)2 center is covalently linked to four RuII(bpy)3-like moieties by bridged bis(bipyridine) Ln ligands, have been synthesized and characterized. The electrochemical, photophysical, and photochemical properties of these complexes have been investigated in CH3CN. The cyclic voltammograms and rotating-disk electrode curves of the three complexes show the presence of two very close successive reversible oxidation processes corresponding to the Mn2III,IV/Mn2IV,IV and RuII/RuIII redox couples (estimated E1/2 approximately 0.82 and 0.90 V, respectively). The lower potential of the Mn2III,IV subunit compared to those of the RuII moieties indicates that the RuIII species can act as an efficient oxidant toward the Mn2III,IV core. The two oxidized forms of the complexes [Mn2IV,IVO2[RuII(bpy)2(Ln)]4]12+ (2a-c) and [Mn2IV,IVO2[RuIII(bpy)2(Ln)]4]16+ (3a-c) obtained in good yields (>90% for 2a-c and >85% for 3a-c) by sequential electrolyses are very stable. Photophysical studies show that the 3MLCT excited state of the Ru(bpy)3 centers is moderately quenched by the Mn2III,IV(micro-O)2 core (15-25% depending on the length of the bridging alkyl chain). Nevertheless, this energy transfer can be easily short-circuited in the presence of an external irreversible electron acceptor like the (4-bromophenyl)diazonium cation, by an electron transfer leading, in a stepwise fashion, to the stable one- and five-electron-oxidized species 2a-c and 3a-c, respectively, also in good yields, under continuous irradiation of the solutions. Electro- and photoinduced oxidation experiments have been followed by UV-visible and electron paramagnetic resonance spectroscopy.     

O-Alkylation of oxime with N-vinyl lactams induced by radical cation

Radical cation promoted O-alkylation of oxime with N-vinyllactam was achieved under base free condition by using catalytic tris(4-bromophenyl)aminium cation radical () as an initiator to produce the corresponding oxime ether in high yields.     

Photocatalytic hydrogen evolution based on efficient energy and electron transfers in donor-bridge-acceptor multibranched-porphyrin-functionalized platinum nanocomposites

Two donor-bridge-acceptor conjugates (5,10,15,20-tetrakis[4-(N,N-diphenylaminobenzoate)phenyl] porphyrin (TPPZ) and 5,10,15,20-tetrakis[4-(N,N-diphenylaminostyryl)phenyl] porphyrin (TPPX)) were covalently linked to triphenylamine (TPA) at the meso-position of porphyrin ring. The triphenylamine entities were expected to act as energy donors and the porphyrins to act as an energy acceptor. In this paper, we report on the synthesis of these multibranched-porphyrin-functionalized Pt nanocomposites. The conjugates used here not only served as a stabilizer to prevent agglomeration of Pt nanoparticles, but also as a light-harvesting photosensitizer. The occurrence of photoinduced electron-transfer processes was confirmed by time-resolved fluorescence and photoelectrochemical spectral measurements. The different efficiencies for energy and electron transfer in the two multibranched porphyrins and the functionalized Pt nanocomposites were attributed to diverse covalent linkages. Moreover, in the reduction of water to produce H(2), the photocatalytic activity of the Pt nanocomposite functionalized by TPPX, in which the triphenylamine and porphyrin moieties are bonded through an ethylene bridge, was much higher than that of the platinum nanocomposite functionalized by TPPZ, in which the two moieties are bonded through an ester. This investigation demonstrates the fundamental advantages of constructing donor-bridge-acceptor conjugates as highly efficient photosensitizers based on efficient energy and electron transfer.     

Unsensitized photochemical hydrogen production catalyzed by diiron hydrides

The diiron hydride [(μ-H)Fe(2)(pdt)(CO)(4)(dppv)](+) ([H2](+), dppv = cis-1,2-C(2)H(2)(PPh(2))(2)) is shown to be an effective photocatalyst for the H(2) evolution reaction (HER). These experiments establish the role of hydrides in photocatalysis by biomimetic diiron complexes. Trends in redox potentials suggests that other unsymmetrically substituted diiron hydrides are promising catalysts. Unlike previous catalysts for photo-HER, [H2](+) functions without sensitizers: irradiation of [H2](+) in the presence of triflic acid (HOTf) efficiently affords H(2). Instead of sacrificial electron donors, ferrocenes can be used as recyclable electron donors for the photocatalyzed HER, resulting in 4 turnovers.     

1-二茂铁基-3-(4-烷氧基-3-溴苯基)-1,3-丙二酮的合成及其结构表征

由乙酰基二茂铁(1)与4-长链烷氧基-3-溴苯甲酸甲酯(2)通过酮酯缩合反应, 合成了1-二茂铁基-3-(4-烷氧基-3-溴苯基)-1,3-丙二酮(3). 标题化合物3为首次合成, 具有复杂的共振结构．通过元素分析、红外光谱、核磁共振氢谱对其结构进行了表征. 用X射线单晶衍射法测定了1-二茂铁基-3-(4-十二烷氧基-3-溴苯基)-1,3-丙二酮(3c)的结构, 结果表明: 晶体属于三斜晶系, P-1空间群, a＝0.8677(5) nm, b＝0.8791(5) nm, c＝2.1444(11) nm, α＝101.489(9)°, β＝94.784(10)°, γ＝102.522(9)°, V＝1.5511(14) nm3, Dc＝1.273 g&#8226;cm－3, μ＝1.801 mm－1, F(000)＝618, Z＝2, R1＝0.0597, wR2＝0.1386.     

Synthesis and Crystal Structure of 4-（2-Bromophenyl）-3,4,7,8-tetrahydro- 7,7-dimethyl-1-p-tolylquinoline-2,5（1H,6H）-dione

The title compound 4-（2-bromophenyl）-3,4,7,8-tetrahydro-7,7-dimethyl-1-p-tolylquinoline-2,5（1H,6H）-dione 1 （C24H24BrNO2, Mr = 438.35） was synthesized and characterized by IR, 1H NMR and elemental analysis. The crystal belongs to monoclinic, space group C2/c with a = 27.565（14）, b = 10.079（5）, c = 15.917（8） A,β = 111.059（9）°, Z = 8, V = 4127（4）A3, Dc = 1.411 g·cm^-3,μ（MoKa） = 2.011 mm^-1, F（000） = 1808, the final R = 0.0417 and wR = 0.1032 for 2393 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the pyridine ring adopts a distorted boat conformation, while another six-membered ring takes a half-chair conformation. In addition, there are non-classical hydrogen bonds of C-H…O and C-H…Br in the structure. The short distance （3.481A） between the adjacent 2-bromophenyl rings indicates the existence of π-π interaction.