Soluble and Planar 2,9-Diazaperopyrenes through Reductive Aromatization of Perylene Diimides: Tunable Emission and Aggregation Behaviors

Reductive aromatization of perylene diimides with acid anhydrides in the presence of Mn or Zn metals provides soluble and planar 2,9-diazaperopyrenes with ester groups at 1,3,8,10-positions. The pivaloxy groups at the peripheral positions can be transformed into a variety of aryl groups through nickel-catalyzed cross-coupling of ester groups. Emission colors of diazaperopyrenes are tunable by the peripheral substituents. The peripheral substituents also affect the aggregation behaviors of 2,9-diazaperopyrenes in the solution and solid states.     

2,9-Diazadibenzoperylene and 2,9-Dimethyldibenzoperylene-1,3,8,10-tetratriflates: Key to Functionalized 2,9-Diazaperopyrenes

The synthesis of 2,9-diaza-1,3,8,10-tetratriflato-dibenzoperylene (DDP 3 a ) and corresponding 2,9-dimethyl-1,3,8,10-tetratriflato-dibenzoperylene (DBP 3 b ) has been developed at multigram scale via reduction of one of the industrially most important high-performance dyes, perylene-3,4,9,10-tetracarboxylic diimide (PTCDI), and of the corresponding dihydroxy peropyrenequinone precursor. The focus of this paper is on the reactivity pattern of 3 a as key intermediate towards highly functionalized 2,9-diazadibenzopyrelenes (DDPs) obtained via catalytic substitution of four triflate by aryl, heteroaryl, alkynyl, aminyl, and O-phosphanyl substituents. The influence of electron-donating substituents (OSiMe₃, OPt-Bu₂, N-piperidinyl), electron-withdrawing (OTf, 3,5-bis-trifluoromethyl-phenyl), and of electron-rich π-conjugated (2-thienyl, 4-tert-butylphenyl, trimethylsilyl-ethynyl) substituents on optoelectronic and structural properties of these functionalized DDPs has been investigated via XRD analyses, UV/Vis, PL spectroscopy, and by electroanalytical CV. These results were correlated to results of DFT and TD-DFT calculations. Thus, functionalized DPPs with easily tunable HOMO and LUMO energies and gap became available via a new and reliable synthetic strategy starting from readily available PTCDI.     

Synthesis,Spectral, and Structural Characterization of Bisthiocarbohydrazone Derivatives

Abstract

Bisthiocarbohydrazone derivatives of three heterocyclic ketone ligands, having a flexible coordination ability; 1, 5-bis (2-acetylthiophene) thiocarbohydrazone; 1, 5-bis (2-acetylfuran) thiocarbohydrazone; and 1, 5-bis (2-acetylpyrrole) thiocarbohydrazone were synthesized and characterized by elemental analysis, UV-visible, FT-IR, cyclic voltammetry, and ¹H and ¹³C-NMR spectral studies. All bisthiocarbohydrazone exhibited the thioketone—thioenol tautomeric forms, as evidenced by IR spectral data and single crystal X-ray diffraction studies of 1, 5-bis (2-acetylfuran) thiocarbohydrazone and 1, 5–bis (2-acetylpyrrole) thiocarbohydrazone.

Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional figures and tables.     

Reductive Amination Reaction for the Functionalization of Cellulose Nanocrystals

Cellulose nanocrystals (CNCs) represent intriguing biopolymeric nanocrystalline materials, that are biocompatible, sustainable and renewable, can be chemically functionalized and are endowed with exceptional mechanical properties. Recently, studies have been performed to prepare CNCs with extraordinary photophysical properties, also by means of their functionalization with organic light-emitting fluorophores. In this paper, we used the reductive amination reaction to chemically bind 4-(1-pyrenyl)butanamine selectively to the reducing termini of sulfated or neutral CNCs (S_CNC and N_CNC) obtained from sulfuric acid or hydrochloric acid hydrolysis. The functionalization reaction is simple and straightforward, and it induces the appearance of the typical pyrene emission profile in the functionalized materials. After a characterization of the new materials performed by ATR-FTIR and fluorescence spectroscopies, we demonstrate luminescence quenching of the decorated N_CNC by copper (II) sulfate, hypothesizing for these new functionalized materials an application in water purification technologies.     

Flavin Derivatives with Tailored Redox Properties: Synthesis,Characterization, and Electrochemical Behavior

This study establishes structure–property relationships for four synthetic flavin molecules as bioinspired redox mediators in electro‐ and photocatalysis applications. The studied flavin compounds were disubstituted with polar substituents at the N1 and N3 positions (alloxazine) or at the N3 and N10 positions (isoalloxazines). The electrochemical behavior of one such synthetic flavin analogue was examined in detail in aqueous solutions of varying pH in the range from 1 to 10. Cyclic voltammetry, used in conjunction with hydrodynamic (rotating disk electrode) voltammetry, showed quasi‐reversible behavior consistent with freely diffusing molecules and an overall global 2e^?, 2H⁺ proton‐coupled electron transfer scheme. UV/Vis spectroelectrochemical data was also employed to study the pH‐dependent electrochemical behavior of this derivative. Substituent effects on the redox behavior were compared and contrasted for all the four compounds, and visualized within a scatter plot framework to afford comparison with prior knowledge on mostly natural flavins in aqueous media. Finally, a preliminary assessment of one of the synthetic flavins was performed of its electrocatalytic activity toward dioxygen reduction as a prelude to further (quantitative) studies of both freely diffusing and tethered molecules on various electrode surfaces.     

大环二羰四胺Ni(Ⅱ)单核和Ni(Ⅱ)-Cu(Ⅱ)双核配合物的合成、表征及电化学性质

合成了一种草酰胺桥联大环二羰四胺Ni(Ⅱ )单核配合物 ,并以此为母体合成了Ni (Ⅱ ) -Cu (Ⅱ )双核配合物 .用元素分析、红外光谱、差热分析、紫外光谱、摩尔电导以及循环伏安等测试手段对配合物进行了表征和电化学性质研究 .经分析 ,标题配合物具有草酰胺桥联结构 ,Ni(Ⅱ )处于平面正方场 ,Cu (Ⅱ )处于八面体场中 .循环伏安测试表明此类配合物能稳定Ni(Ⅲ ) .     

Synthesis,Structural Characterization,and Reductive Cleavage of an Oxygen-Containing Naphthyl Macrocycle

A small macrocycle comprising ether-bridged naphthyl units was prepared in a two-step synthesis. Single-crystal X-ray diffraction of two polymorphs are reported, one of which showed multiple C−H⋅⋅⋅π_naphthyl interactions of a solvent molecule in the cavity of the macrocycle. Chemical reduction led to C−O bond cleavages accompanied by a Z/E isomerization. The resulting twofold negatively charged (E)-1,2-bis(2-naphthyl)ethylene fragment was isolated as its potassium salts. Electronic characterization revealed a singlet ground state, and a marked distortion of the central ethylene unit was observed upon electron uptake.     

新型卟啉衍生物的合成、结构表征和电化学性质的研究

以合成的[5-(4-溴苯基)-10,15,20-三苯基卟啉]锌为底物,通Stille偶联的方法合成5-(4’-氨基-4-联苯基)-10,15,20-三苯基卟啉,[5-(4’-氨基-4-联苯基)-10,15,20-三苯基卟啉]锌配合物以及[5- (4’-甲硫基-4-联苯基)-10,15,20-三苯基卟啉]锌配合物。并用Uv,‘H NMR, IR, Ms, Fs等表征确证了该系列配合物的结构,并用循环伏安法对以上部分产物进行了电化学性质的研究.     

Highly Conjugated Bis(benzo[b]phosphole)-P-oxides: Synthesis and Electrochemical,Optical, and Computational Studies

The first examples of a π-conjugated benzo[b]phosphole P-oxide in which two phosphole P-oxide units are connected by a carbon-carbon double bond are described. The molecules are synthesized as E isomers with respect to the carbon-carbon double bond and exist as stable cis and trans isomers (chiral and meso one respectively) relatively to the two stereogenic P atoms. The optical and electrochemical properties of both isomers have been investigated by experiment and computations.     

Exploring SmBr2-, SmI2-, and YbI2-mediated reactions assisted by microwave irradiation

The use of microwave heating in lanthanide(II) halide (LnX2 = SmBr2, SmI2, and YbI2) mediated reduction and coupling reactions has been investigated for a variety of functional groups including alpha,beta-unsaturated esters, aldehydes, ketones, imines, and alkyl halides. Good to quantitative transformations were obtained within a few minutes without the addition of any co-solvents, such as hexamethyl phosphoramide (HMPA). The redox potential of YbI2 in tetrahydrofuran (THF) has been determined as -1.02+/-0.05 V (versus Ag/AgNO3) by cyclic voltammetry. A large selectivity difference in various reactions was observed depending on the redox potential of the LnX2 reagent. The more powerful reductant, SmBr2, afforded mainly pinacol-coupling products of ketones whereas the weaker reductant YbI2 afforded mainly reduction products. The results indicate that the reducing power of LnX2 has a large impact on not only the pinacol coupling/reduction product ratio of ketones but also on other substrates in which there are competing coupling and reduction reactions. The use of in situ generated LnX2 has also been explored and proven useful in many of these reactions.     

Synthesis,optical, and structural properties of bisphenol-bridged aromatic cyclic phosphazenes

Phenoxy- and naphthoxy-substituted bisphenol-bridged cyclic phosphazenes were synthesized in 2 steps and their thermal, photophysical, and electrochemical properties were investigated. The structures of the cyclic phosphazene compounds were determined by ESI-MS mass spectrometry and ¹ H, ¹³ C, and ³¹ P NMR spectroscopies. The photophysical studies of phenoxy- and naphthoxy-substituted bridged cyclophosphazenes were investigated by means of absorption and fluorescence spectroscopies in different solvents. Thermal and electrochemical properties of the target compounds were also studied. Furthermore, the excimer emissions through intramolecular interactions in solution and in solid state were investigated by fluorescence spectroscopy and the theoretical calculations were performed in detail using DFT.     

1,4-二氢吡啶衍生物合成方法的改进和芳构化研究

改进了Hantzsch合成法,通过一锅煮合成1,4-二氢吡啶衍生物,大大缩短了反应时间,操作简便,发现氯化铁是一个较好的1,4-二氢吡啶衍生物芳构化的氧化剂。     

Fluoride‐Catalyzed Methylation of Amines by Reductive Functionalization of CO2 with Hydrosilanes

An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO₂ with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO₂ with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO₂. The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride‐promoted hydride transfer from the hydrosilane to CO₂/formamide was proposed. Striking features of this metal‐free protocol are formylation and methylation of amines by reductive functionalization of CO₂ with hydrosilanes and mild reaction conditions.     

对-氢醌金属配合物：合成，结构及电化学性质

A new Chromium(Ⅲ) complex, [Cr(Hcah)(H₂O)₂]·2H₂O, where H₄cah=2-[N,N-bis(carboxymethyl)aminome-thyl] hydroquinone (H₄cah), has been synthesized and characterized using X-ray diffraction single crystal structure determination, IR and elemental analysis. The complex belongs monoclinic, space group P2₁/c, with a=0.792 05(4) nm, b=1.008 63(6) nm, c=1.920 40(10) nm, β=93.069(4)°, V=1.531 98(14) nm³, and Z=4. The cyclic voltametric analysis shows that the electron transfer in the electrode reaction is irreversible for Cr(Ⅲ)/Cr₂O₇^2- and Cr(Ⅲ)/Cr(Ⅱ) redox couples while reversible for process of interchange from p-Hydroquinone to p-semiquinones. CCDC: 666208.     

Synthesis of Primary Amines by One-Pot Reductive Amination of Aldehydes

We report here a novel, one-pot, two-step reductive amination of aldehydes for the atom-economical synthesis of primary amines. The amination step has been carried out with hydroxylammonium chloride and does not require the use of a base. In the subsequent reduction step, a metal zinc/hydrochloride acid system has been used. This method is applicable to both aliphatic and aromatic aldehydes. The operational simplicity, the short reaction times, and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of aldehydes.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

超级电容器纳米氧化锰电极材料的合成与表征

以聚乙二醇为分散剂,利用高锰酸钾和醋酸锰溶液之间的化学共沉淀法制备纳米水合氧化锰.借助SEM,TEM,FT-IR,XRD和BET分析手段对样品结构及性能进行表征.研究结果表明,SEM和TEM显示所得粉体为纳米粉体,粒径大约为10～30nm左右,XRD分析表明该粉体为无定型a-MnO₂·nH₂O,FT-IR分析表明获得的粉体为水合物,BET测试比表面积达160.7m²/g.以氧化锰为研究电极,饱和甘汞电极(SCE)为参比电极,铂片为辅助电极的三电极体系中,以1 mol/L的Na₂SO₄溶液为电解液,通过循环伏安法研究其电化学行为.实验结果表明,纳米氧化锰是理想的超级电容器电极材料,在电位窗口为-0.2～0.9V(vs.SCE)范围内,扫描速度为4mV/s,其比电容达到203.4 F/g.     

Electrochemical Synthesis and Characterization of Electroactive Conducting Polypyrrole Polymers

Conducting/electroactive polypyrrole polymers are synthesized electrochemically on glassy carbon in various electrolytes (counterions). The polymers' electroactivity is measured using cyclic voltammetry. The electrolytes are chloride, nitrate, p-toluene sulfonate, dodecyl sulfate, and dodecylbenzenesulfonate of sodium and potassium ferrocyanide. It is found that the electrolyte (dopant) markedly affects the redox behavior of the polypyrrole films.     

Shape‐Persistent Oligothienylene–Ethynylene‐Based Dendrimers: Synthesis,Spectroscopy and Electrochemical Characterization

A series of novel structurally well‐defined oligothienylene–ethynylene‐based dendritic macromolecules up to the 3rd generation (G3) were successfully synthesized by a combination of Pd‐catalyzed Sonogashira‐type cross‐coupling and oxidative homocoupling steps. Oxidative homocoupling of dendrons successfully afforded dendrimers up to the 2nd generation (G2). In contrast, the G3 dendrimer was effectively prepared by a four‐fold Sonogashira‐type cross‐coupling reaction. All compounds showed broad and structureless absorption and emission spectra arising from the presence of different π‐conjugated chromophores. With increasing generation, a bathochromic shift of the π–π* absorption band and an increase of the absorption coefficient were observed. The insertion of ethynylene groups into the conjugated dendrimer backbone resulted in a hypsochromic shift compared to all‐thiophene dendrimers reported earlier by our group. All dendritic compounds are fluorescent and showed moderate quantum efficiencies due to an effective intramolecular charge‐transfer (ICT) process. Cyclic voltammetry measurements also revealed the presence of multiple π‐conjugative pathways that show very broad oxidation waves for higher generations. HOMO–LUMO energy levels of these dendrons and dendrimers were estimated from optical and redox measurements and the calculated band gaps were within the range of 3.3 to 2.4 eV, typical for oligo‐ and polythiophenes. Electrochemical polymerizations of several desilylated compounds were performed and characterization of the films is reported. Preliminary bulk heterojunction solar cells that utilise these ethynylated dendrimers as the donor and [6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PCBM[60]) as the acceptor showed moderate efficiencies ranging from 0.18–0.64 %.     

Synthesis and Characterization of Conducting Copolymers of Thiophene Derivatives

Electrochemical copolymerizations of N¹,N²-bis(thiophen-3-ylmethylene)benzene-1,2-diamine (TMBD), 4-methyl-N¹,N²-bis (thiophen-3-ylmethylene)benzene-1,2-diamine (MTMBD) and 4-nitro-N¹,N²-bis(thiophen-3-ylmethylene)benzene-1,2-diamine (NTMBD) with 3,4-ethylenedioxy thiophene (EDOT) were carried out in CH₃CN/LiClO₄ (0.1 M) solvent–electrolyte couple via potentiodynamic electrolysis. The resulting copolymers were characterized by cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The conductivity measurements of copolymers and PEDOT were carried out by the four-probe technique.     

C60Ru(OCOCF3)(CO)(PPh3)配合物的合成及性能

富勒烯;钌配合物;循环伏安法;C60Ru(OCOCF3)(CO)(PPh3)配合物的合成及性能