Synthesis and application of near-infrared absorbing morpholino-containing aza-BODIPYs

Morpholino-containing aza-BODIPYs at 3,5-positions were synthesized. The maxima absorption and emission of these dyes locate at the near-infrared region. Aza-BODIPY 1 with the morpholino group as a pH-sensitive functionality could be used to be a pH probe, and the dramatic increase in fluorescence intensity at 675 nm by about 1500 folds. Moreover, the singlet oxygen generation of PS 2 with the dibromo groups at 2,6-positions was more effective than that of the parent dye 1.     

Synthesis of soluble oligothiophenes bearing cyano groups, their optical and electrochemical properties

The synthesis and the characterization of twelve new soluble oligothiophenes, possessing two to four 3,4-dicyanothiophene units in their backbone, are described. These semiconductors are prepared through Stille coupling and/or homo-coupling reactions. Cyclic voltammetry studies have been performed to evaluate their stability as n-type semiconducting materials under ambient conditions. The measured electrochemical and optical properties are fully supported by quantum-chemical calculations.     

1,2,5-Thiadiazole 2-oxides: selective synthesis,structural characterization,and electrochemical properties

A new general procedure for the selective synthesis of 1,2,5-thiadiazole 2-oxides (including fused derivatives) 8a,b,c,g,h from the reaction of vic-glyoximes with S₂Cl₂ and pyridine in acetonitrile was elaborated together with general procedure for the synthesis of 1,2,5-thiadiazoles 7a–i, 10, 12, and 14 from the same starting materials and reagents. Molecular structures of 3,4-dimethyl-1,2,5-thiadiazole 2-oxide 8a and [1,2,5]thiadiazolo[3,4-b]quinoxaline 10 were confirmed by single-crystal X-ray diffraction. Electrochemical properties of 1,2,5-thiadiazole 2-oxides 8 were studied by cyclic voltammetry and different behavior was observed for monocyclic and benzo-fused derivatives. With compounds 8g and 17, previously unknown deoxygenation of 2,1,3-benzothiadiazole 1-oxides was discovered by electrochemical reduction, and resulted 2,1,3-benzothiadiazoles 7g and 19 were detected in the forms of their radical anions by EPR spectroscopy combined with DFT calculations.     

Synthesis of bis-2H and 4H-chalcogenapyrans and benzochalcogenapyrans via Pd catalyzed dimerization of Fischer type carbene complexes: redox properties and electronic structure of these new extended electron rich molecules

Extended electron rich bis-chalcogenapyrans and bis-benzochalcogenapyrans have been synthesized by Pd⁰ catalyzed dimerization of α- and γ-methylene chalcogenapyran and benzochalcogenapyran Fischer type carbene complexes. Voltammetric studies performed on these molecules show a single two-electron wave around 0 V versus SCE, which is ascribed to the oxidation of the neutral form in radical and dipyrylium cations. DFT calculations show that the oxidation leads to a rotating movement around the central C-C bond and suggest that the solvent plays a major role in the observation of the two one-electron systems. Furthermore, according to the structure, these molecules are likely to be reduced at very low potential (E=−1.5 V vs SCE) via a two-electron transfer reaction.     

New p-aminophenol-based dendritic melamines. Iterative synthesis,structure, and electrochemical characterisation

Avoiding any protective–deprotective step, the synthesis of new (G-0, -1, -2) dendritic melamines is reported. Their construction consisted of chemoselective S_N2–Ar amination of cyanuric chloride with p-aminophenol (peripheral unit) and piperazine or 4,4′-bipiperidine (linkers). This novel class of amino-s-triazines is primarily investigated by DFT calculations (optimal geometry and electronic structure) in tandem with (VT) ¹H NMR spectroscopy providing details of the rotational diastereomerism about the C(s-triazine)-N(exocyclic) partial double bonds, solvation effects and conformation of the linkers. These data are subsequently exploited in electrochemical investigations (cyclic voltammetry on the Pt electrode/DMSO, 0.1 M KCl). Two reversible electron-transfer phenomena have been observed. Thus, depending on the variable π-deficiency strength of the s-triazine ring acting as the EWG on the adjacent NH group and the ability of the latter to undergo redox processes in tandem with the phenolic p-HO group, two electrochemical pathways are proposed, namely the p-benzoquinonimine route and the electropolymerization route.     

Synthesis of silver nanowires and their applications in the electrochemical detection of halide

A silver nanowires modified platinum (Ag NWs/Pt) electrode was developed for simultaneous and selective determination of chloride, bromide and iodide ions by cyclic voltammetry in aqueous solutions. Silver nanowires were synthesized by an l-cysteine-assisted poly (vinyl pyrrolidone) (PVP)-mediated polyol route. X-ray diffraction (XRD) and scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) were employed to investigate the prepared nanowires. The intrinsic high surface area and the fast electron transfer rate ascribed from the nanowire structure could further improve halide detection performance. The determination was based on measurement of the well-separated oxidation peak currents of respective silver halides formed on the surface of silver during an anodic potential sweep. The concentration range was linear from 50 μM to 20.2 mM for bromide and iodide and 200 μM to 20.2 mM for chloride, and the sensitivity was 0.059 μA/mM, 0.042 μA/mM and 0.032 μA/mM for chloride, bromide and iodide, respectively. The correlation coefficient was 0.999 in each case. The Ag NWs/Pt electrode offered a useful platform for the development of a highly sensitive halide sensor.     

Synthesis and properties of a series of porphyrin-nicacid dyads and their Mn and Zn complexes

In this article, a series of porphyrin-nicacid dyads and their Mn and Zn complexes were synthesized and characterized by elemental analysis, UV–Vis, IR, MS, and ¹H NMR spectroscopies. Fluorescence studies show that for increasing length of alkoxy chains the fluorescence intensity and quantum yield of the porphyrin ligands is C₂ > C₃ > C₄ > C₅ > C₆ > C₁₀. Electrochemical results indicate that the length of side chain has little effect on the redox potential.     

Donor/acceptor-substituted anthradithiophene materials: synthesis, optical and electrochemical properties

The synthesis and characterization of two new anthradithiophene (ADT) derivatives bearing electron donating (triphenylamine) or accepting (5-formylthiophen-2-yl unit) moieties have been performed to assess their potential as materials for organic photovoltaics. Optical spectroscopy was used to evaluate the effect of electron rich/poor substituents on the visible absorption spectrum and on the stability towards photo-oxidation. The results are interpreted with the assistance of quantum-chemical calculations and cyclic voltammetry experiments.     

Synthesis of redox-active biscalix[4]quinones and their electrochemical properties

Biscalix[4]arenes, 7 and 8, have been synthesized by a one-pot coupling method and a stepwise approach, respectively. One-pot reaction in a pressurized vessel resulted in the symmetric biscalix[4]arene 7 in high yield. Oxidation of compounds 7 and 8 by Tl(CO₂CF₃)₃ in CF₃COOH yielded biscalix[4]quinones, 9 and 10, respectively. Preliminary electrochemical studies by cyclic voltammetry of 9 and 10 show significant changes of their voltammograms upon addition of Na⁺.     

Synthesis of polyamines with pendant cyanoimidazole units and their electrochemical properties

The 2-(1-methyl-4,5-dicyanoimidazolyl) group was attached to poly(diallylamine) and polyethylenimine, affording polymers containing an electron-withdrawing pendant group. The key to their preparation is high reactivity of 1-methyl-2-fluoro-4,5-dicyanoimidazole (1) toward nucleophilic aromatic substitution (NAS) reactions with aliphatic amines. Cyclic voltammograms of these polymers show reduction waves at −2.6 to −2.7 V vs. Ag/Ag⁺ but no reoxidation waves, unlike those of monomeric and oligomeric model compounds, which are quasi-reversible. The cyclic voltammetry studies of oligomeric model compounds with different alkyl spacers show that the degree of quasi-reversibility decreases as dicyanoimidazoles are crowded together in a molecule, suggesting that a certain degree of chemical reaction occurs between reduced dicyanoimidazole groups. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2619–2629, 1998     

Use of Wittig reaction for the synthesis of conjugated Aza-BODIPYs and their spectral and electrochemical properties

The 2-formyl 1,3,5,7-tetraaryl aza-BODIPY and 2-formyl-6-bromo 1,3,5,7-tetraaryl aza-BODIPY were subjected to Wittig reaction with three different ylides under simple reaction conditions and afforded the conjugated aza-BODIPYs in high yields. The aza-BODIPYconjugates resulted from 2-formyl-6-bromo aza-BODIPYs were reacted further with 4-anisyl boronic acid under mild Pd(0) coupling conditions and afforded 1,2,3,5,7-pentaaryl aza-BODIPYconjugates. The method works efficiently and allows to introduce different substituents at the aza-BODIPY core. All compounds were characterized by HRMS, 1D, 2D NMR, absorption, fluorescence and electrochemical techniques. The spectral and electrochemical studies indicated that the introduction of conjugated substituents at the aza-BODIPY core alter the electronic properties significantly.     

Synthesis, spectroscopic and electrochemical properties of manganese, nickel and iron octakis-(2-diethylaminoethanethiol)-phthalocyanine

The syntheses, spectroscopic and electrochemical properties of manganese (3), nickel (4) and iron (5) phthalocyanine complexes, octa-substituted at the peripheral positions with diethlyaminoethanethiol substituent, are reported. The electrochemistry of these complexes and the corresponding cobalt complex (6) are reported. Complex 3 showed two reversible reduction couples attributed to the Mn^IIIPc⁻²/Mn^IIPc⁻² (E_½ = −0.12 V versus Ag|AgCl) and Mn^IIPc⁻²/Mn^IIPc⁻³ (E_½ = −0.82 V versus Ag|AgCl) species. Two ring-based reduction couples were also observed for complex 4. Two reduction couples, assigned to the Fe^IIPc⁻²/Fe^IPc⁻² (E_½ = −0.35 V versus Ag|AgCl) and Fe^IPc⁻²/Fe^IPc⁻³ (E_½ = −0.96 V versus Ag|AgCl) species, and an oxidation couple, attributed to Fe^IIIPc⁻²/Fe^IIPc⁻² (E_½ = 0.26 V versus Ag|AgCl) species, were observed. For complex 6, two reductions and one oxidation were also observed with the potential range of 1.2 to −1.8 V versus Ag|AgCl Spectroelectrochemical studies were used to confirm some of the assigned processes.     

新型不对称镍酞菁的合成、表征及光电性质

通过改进传统的酞菁合成方法, 得到了一种新的不对称酞菁2-(4-异丙基苯氧基)-9(10),16(17), 23(24)-三(4-叔丁基苯氧基)酞菁镍(简称NiPc2), 并通过质谱、红外光谱及紫外-可见-近红外光谱对其进行了表征, 分析了其可能的形成机理以及循环伏安性质. 这种新的不对称酞菁在近红外光区有明显的吸收峰, 并且其固体紫外-可见光谱的Q带发生红移, 说明形成了J-聚集体.     

Synthesis and electrochemical characterisation of a near infrared absorbing oxo vanadium(IV) octapentylthio-phthalocyanine

The synthesis of an α-substituted phthalocyanine oxo vanadium(IV) 1,4,8,11,15,18,22,25-octapentathiophthalocyanine (4) which absorbs at 850 nm in dichloromethane is reported. The complex is purple in colour and becomes green on reduction. The cyclic and square wave voltammetries of the complex show five redox couples. The spectroelectrochemical data showed only ring based processes. The ring reduced species is observed at wavelengths greater than 680 nm rather than the usual 500–600 nm range typical of ring reduced phthalocyanine complexes.     

Synthesis, spectroscopic and electrochemical property of an unsymmetrical porphyrin and its Zn compound

<正>In this article,a new 5-(p-maleicaminophenyl)-10,15,20-triphenylporphyrin(H_2P) and relative zinc compound(ZnP) were synthesized and characterized by means of elemental analyses,UV-vis,IR,MS and ~1H NMR spectroscopies.Furthermore,we have investigated the fluorescence spectroscopy of these compounds.The oxidation and reduction properties of the compounds were studied by the cyclic voltarnmetry,the oxidation-reduction potentials were obtained.     

Synthesis,electrochemical and anti-microbial study of 2,5-diamino benzoquinones

Fifteen symmetric and unsymmetric 2,5-diamino benzoquinones have been synthesized and their electrochemical activity was studied by cyclic voltammetry. Presence of electron donating substituent like amino group found to shift the half wave potential towards more negative value which is more prominent in benzyl amino substituted amino benzoquinones (ABQs). All the compounds were checked for their anti-bacterial and anti-fungal activity by agar well diffusion technique. The more negative E_1/2 values of benzyl amino substituted ABQs make them more active towards various bacterial and fungal speciesas is evident from MIC values.     

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.     

Synthesis and properties of perfluoroalkylated TIPS-pentacenes

The introduction of perfluoroalkyl (Rf) groups into polycyclic aromatic hydrocarbons (PAHs) is a potential strategy for developing air-stable electron-acceptors that are useful for manufacturing novel n-type organic semiconductors. This paper describes a facile synthetic method for 9,13-bis[(triisopropylsilyl)ethynyl]pentacene (“TIPS-pentacene”) derivatives bearing two or four Rf groups at peripheral regions. The molecular structures of newly synthesized TIPS pentacenes bearing four Rf groups were established by single-crystal X-ray analysis. The Rf-substituted TIPS-pentacenes are stable both in solutions and in the solid state under ambient conditions, probably because of the combination of the TIPS-ethynyl and Rf groups. The Rf groups stabilize the π-orbitals of the TIPS-pentacene framework and improve the electron-accepting properties, as evidenced by electrochemical measurements and photoelectron yield spectroscopy (PYS).     

Synthesis and electrochemical studies of organometallic cobalt(III) complexes with substituted benzonitrile chromophores: NMR spectroscopic data as a probe on the second-order non-linear optical properties

The family of organometallic Co(III) benzonitrile derivatives of general formula [CoCp(dppe)(p-NCR)][PF₆]₂ (R = C₆H₄NMe₂, C₆H₄NH₂, C₆H₄OMe, C₆H₄C₆H₅, C₆H₅, C₆H₄C₆H₄NO₂, and C₆H₄NO₂) have been synthesized. Spectroscopic and electrochemical data were analyzed in order to evaluate the extent of electronic coupling between the organometallic fragment and the nitrile ligands. An attempt of correlation between NMR spectroscopic data and the second-order non-linear optical properties is presented, based on this work and available published data for related η⁵-monocyclopentadienyliron, ruthenium and nickel complexes.     

Pentacyanido(L)ferrate(III) complexes: Crystal structures, electrochemical and DFT studies (L = pyrazine, 4,4′-bipyridine, azide)

The crystal structures of two pentacyanido(L) ferrate(III) complexes, [P(C₆H₅)₄]₂[Fe(CN)₅(prz)]·4H₂O 1, [P(C₆H₅)₄]₂[Fe(CN)₅(4,4′-bipy)]·3H₂O 2, have been solved. Within the two complex anions the iron atoms are hexacoordinated by five cyanido ligands, the sixth position being occupied by the nitrogen atom arising from pyrazine and, respectively, 4,4′-bipyridine. The electrochemical properties of compounds 1, 2 and of the azido derivative, (Ph₄As)₂[Na(H₂O)₄][Fe(CN)₅(N₃)] 3, have been investigated by cyclic voltammetry. A relatively complicated redox behavior of these complexes was found, due especially to the electron transfer involving the central metallic ion that changes reversibly its oxidation state (Fe^III/Fe^II redox site) and also to the coligand (4,4′-bipyridine, pyrazine or azide) which intervenes in a distinct electron transfer. The experimental data have been rationalized through DFT calculations.