Syntheses and modifications of bisdiazonium salts of 3,8-benzo[c]cinnoline and 3,8-benzo[c]cinnoline 5-oxide onto glassy carbon electrode and the characterization of the modified surfaces

The goal of this study was to prepare novel glassy carbon electrode surfaces using two similar bis-diazonium salts, 3,8-benzo[c]cinnoline (3,8-BCC-BDAS) and 3,8-benzo[c]cinnoline 5-oxide (3,8-BCCNO-BDAS) at the glassy carbon (GC) surface. These diazonium salts were reduced electrochemically and covalently electrografted onto the glassy carbon electrode surface to form modified electrodes. Electrochemical reduction of 3,8-BCC-BDAS and 3,8-BCCNO-BDAS salts on the electrode surface yielded a compact and stable film. The existence of BCC moieties on the GC surface was characterized by X-ray photoelectron spectroscopy, reflectance-adsorption infrared spectroscopy, cyclic voltammetry, ellipsometry, and electrochemical impedance spectroscopy. The stability and working potential range of the novel modified electrodes were also studied. The possibility of analytical application of these novel surfaces for inorganic cations and especially selectivity to copper ions was investigated. 3,8-diaminobenzo[c]cinnoline (3,8-DABCC) and its 5-oxide derivative (3,8-DABCCNO) were synthesized from the reductive cyclization of 2,2′-dinitrobenzidine and prepared their bisdiazonium salts via the tetrazotization reactions of the diamines with NaNO₂. The structures of 3,8-DABCC and 3,8-DABCCNO and their corresponding bisdiazonium salts are confirmed by spectral analysis.     

Investigations of a novel process to the framework of benzo[c]cinnoline

A novel synthetic process leading to the framework of benzo[c]cinnoline has been discovered and investigated. The process is composed of two separate reactions, the first of which is a partial reduction of the nitro groups of the 2,2'-dinitrobiphenyl, a process that we believe proceeds via a SET mechanism to yield the hydroxyamino and nitroso groups. In the following step the cyclization takes place under formation of the -N=N- bond. We believe that this process take place via a radical mechanism through the nitroso radical anion. The novel process affords either benzo[c]cinnoline or benzo[c]cinnoline N-oxide, both in high yields, 93% and 91%, respectively. To obtain benzo[c]cinnoline, the reaction is conducted with an alcohol as solvent and an alkoxide as the base, while for benzo[c]cinnoline N-oxide, water is used as solvent with sodium hydroxide as the base. To establish the latter procedure, statistical experimental design and multivariate modeling were utilized to reveal the response surface for the reaction and to determine the optimal conditions for the reaction. A proposal for the complex reaction mechanism is given. During the corroboration of the mechanism, a new deoxygenation reaction for converting benzo[c]cinnoline N-oxide into benzo[c]cinnoline was discovered. The reaction is conducted by treating the N-oxide with sodium ethoxide at elevated temperature to achieve near-quantitative conversion into benzo[c]cinnoline in a yield of 96%.     

Mass spectral fragmentation mechanisms of some dibenzo[c,f][1,2] diazepines

The fragmentation mechanisms of 11H-dibenzo[c,f][1,2]diazepine (I), its 3,8-dichloro derivative (II), 3,8-dichlorodibenzo[c,f] [1,2]diazepin-11-one (III) and 3,8-dichloro-11H-dibenzo-[c,f][1,2]diazepin-N-oxide (IV) are discussed. The initial loss of molecular nitrogen is characteristic of I, II and III. Compound IV has a strong molecular ion, that competitively eliminates cither NO or Cl- and N₂O. The common radical ion, m/166 e present in the mass spectra of I, fluorene, 2-methyl-9,10-anthraquinone and 2-methylbenzo[c]cinnoline, appears to be formed in different states.     

Solvent effect on self-assembled structures of 3,8-bis-hexadecyloxy-benzo[c]cinnoline on highly oriented pyrolytic graphite

3,8-Bis-hexadecyloxy-benzo[c]cinnoline (BBC16) self-assembled into two structures at highly oriented pyrolytic graphite (HOPG) surface: one was formed by molecules with a V-like configuration (C2v symmetry) and the other by molecules with a Z-like configuration (C(s) symmetry). The self-assembled structures could be tweaked by the solvents used. In the self-assembled monolayers (SAMs) on HOPG, the BBC16 molecule adopted the V-like configuration in polar solvents and the Z-like configuration in nonpolar solvents. Moreover, the solvent viscosity, solvent dissolvability of BBC16, and substrate temperature also played some roles in tuning the two-dimensional self-assembled structures.     

EuCl_3在氯化1-丁基-3-甲基咪唑中的电化学性质

应用循环伏安法研究了Eu3+在亲水性离子液体—氯化1-丁基-3-甲基咪唑([BMIM]Cl)中的电极过程.实验表明,工作电极为玻碳电极时,[BMIM]Cl的电化学窗口为-1.7～0.80V(vs.Ag/AgCl).Eu3+在[BMIM]Cl中被还原为Eu2+,此电极反应受电荷迁移和物质扩散共同控制.当体系温度从55℃升高到75℃时,Eu3+在[BMIM]Cl中的扩散系数D从3.75×10-9cm2/s变化到1.32×10-8cm2/s,该反应活化能Ea为62.6kJ/mol.     

Formation of 1,10-disubstituted benzo

The first 1,10-heterodisubstituted benzo[c]cinnoline derivative 1 was prepared from the trinitrobiphenyl 2. Investigation of the mechanism of ring closure in 2, 5, and 8 revealed a complex reduction-oxidation-cyclization sequence. The mechanism is discussed in light of the stereoelectronic demands of the substituent functionalities. Benzo[c]cinnoline derivative 1 [C15H15N3S, monoclinic, P2(1)/c: a = 7.4063(3) A, b = 10.3739(5) A, c = 16.7642(8) A, beta = 91.816(1) degrees, Z = 4] and its 5-N-oxide 7(N5) [C18H18N3OS, triclinic, Pi: a = 8.1510(7) A, b = 8.6106(7) A, c = 12.102(1) A, alpha = 86.262(1) degrees, beta = 83.364(1) degrees, gamma = 74.711(1) degrees, Z = 4] were structurally characterized and showed a significant helical distortion of the heterocyclic ring. Oxidation of 1 with NCS or triamine 12 with PhI(OAc)2 led to a new heterocyclic ring system, ylide 13. Both benzo[c]cinnoline 1 and ylide 13 were characterized spectroscopically and the absorption spectra were correlated with the results of ZINDO calculations.     

Synthesis of pyrrolo[1,2-b]cinnolines

The synthesis of the pyrrolo[1,2-b]cinnoline analogs 2 and 4–13 is described. The key step of this synthesis involves an intramolecular aromatic halide displacement on [2-(2-halobenzoyl)pyrrol-1-yl]carbamic acid esters. Several reactions of these cinnoline analogs with electrophilic reagents have been investigated.     

A versatile synthesis of diverse 3,4-fused cinnolines via the base-catalysed condensation of 2-amino-2'-nitrobiaryls

Benzo[c]cinnolines, thieno[3,2-c]cinnolines, pyrido[3,2-c]cinnolines and the previously undescribed quinoxalino[6,7-c]cinnoline ring system are conveniently prepared by a short synthetic route comprised of Suzuki coupling, base-catalysed cyclisation and deoxygenation. The use of tandem borylation-Suzuki coupling further extends the scope of this process to include highly substituted benzo[c]cinnolines.     

Characterization of a 2‐Benzo[c]cinnoline Modified Glassy Carbon Electrode by Raman Spectroscopy,Electrochemical Impedance Spectroscopy,and Ellipsometry

This work describes the characterization of the grafted 2‐benzo[c]cinnoline (2BCC) molecules at a glassy carbon (GC) electrode surface by voltammetry and spectroscopy. Attachment of the molecule to the carbon substrate was achieved by the electrochemical reduction of 2‐benzo[c]cinnoline diazonium salt (2BCC‐DAS). GC electrode modification was carried out in aprotic solution with 2BCC diazonium salt. Dopamine (DA) and ascorbic acid (AA) were used to prove the surface modification to see the blockage of the electron transfer. The presence of 2BCC at the GC electrode surface was characterized by cyclic voltammetry and Raman spectroscopy. Raman spectroscopy was used to monitor molecular bound properties of the adsorbates at the 2BCC‐GC surface and confirm the attachment of 2BCC molecules onto the GC surface. The thickness of the 2BCC film on GC was also investigated by ellipsometric measurement.     

The synthesis of 6,9-difluorobenzo[g]quinoline-5,10-dione. Displacements of the fluorides by diamines which lead to 6,9-bis[(aminoalkyl)amino]benzo[g]quinoline-5,10-diones

The synthesis of 6,9-difluorobenzo[g]quinoline-5,10-dione ( 3b ) is described. Facile ipso substitutions of the fluorides from 3b by diamines readily yield the corresponding 6,9-bis[(aminoalkyl)amino]benzo-[g]quinoline-5,10-diones 2 . The analogue 2d has been synthesized by side arm modifications of dione 8a .     

Amperometric Lactate Biosensor Based on Carbon Paste Electrode Modified with Benzo[c]cinnoline and Multiwalled Carbon Nanotubes

Amperometric lactate biosensor based on a carbon paste electrode modified with benzo[c]cinnoline and multiwalled carbon nanotubes is reported. Incorporation of benzo[c]cinnoline acting as a mediator and multiwalled carbon nanotubes providing a conduction pathway to accelerate electron transfer due to their excellent conductivity into carbon paste matrix resulted in a high performance lactate biosensor. The resulting biosensor exhibited a fast response, high selectivity, good repeatability and storage stability. Under the optimal conditions, the enzyme electrode showed the detection limit of 7.0×10^?8 M with a linear range of 2.0×10^?7 M–1.1×10^?4 M. The usefulness of the biosensor was demonstrated in serum samples.     

离子液体中间硝基苯酚在玻碳电极上的电化学还原行为研究

在[EMIM]Br体系中,以玻碳为工作电极,铂丝为辅助电极,饱和甘汞电极为参比电极,研究了间硝基苯酚的电化学行为.采用循环伏安法和计时电量法,研究了扫描速度、温度和底物浓度等因素对其电化学行为的影响,求得扩散系数D为9.184×10^-7cm²/s,传递系数α为0.37,证明了在[EMIM]Br体系中,此反应是受扩散控制的不可逆反应.     

Some reactions of 3-halogenocinnolines catalysed by palladium compounds

3-Bromo- or 3-iodo-cinnoline (and 4-substituted analogues) are condensed with terminal alkynes in the presence of Pd and Cu compounds as catalysts to give the 3-alkynyl-derivatives. When 4-chloro- or 4-phenoxy-compounds are used, the products react with amines, in the presence of copper(I) iodide, to form pyrrolo[3,2-c]cinnolines and with hydrazines to give either the same ring system or a pyrazolo[4,3-c]cinnoline. Hydrolysis of 3-alkynyl-4-phenoxycinnoline to 3-alkynyl-4(1H)-cinnoline, followed by cyclisation, yields the furo[3,2-c]cinnoline. Attempts to condense 3-halogenocinnolines with alkenes gave variable results: 3-phenyl ethenyl- and 3(2-pyridylethenyl)-4-(1H)-cinnolinones were obtained but 3-bromocinnoline gave the 3,3′-bicinnolinyl. Action of palladium acetate in the presence of ethyl acrylate converted 3-bromo-4-phenoxycinnoline into benzofuro[3,2-c]cinnoline and 3-bromo-4-phenylaminocinnoline into indolo[3,2-c]cinnoline.     

Mass spectrometry of the 11H-dibenzo[c,f][1,2]-diazepine system

The mass spectra of 3,8-dichloro-11H-dibenzo[c,f] [1,2]diazepine, the corresponding diazepin-11-01 and diazepin-11-one and their dihydro and N-oxide derivatives have been recorded. The most important fragmentation of the molecular ions of all diazepines studied was an initial loss of m/e 28, with further fragmentation depending on the 11-substituent. No general pathway was observed for the corresponding N-oxides and dihydro compounds.     

二硫键金属卟啉的合成及电催化还原氧气

以氯化血红素(Ⅰ) 为原料, 经过脱铁、 酯化、 催化加氢、 水解、 酸胺缩合以及络合金属合成了化合物Co(Ⅱ)-[2,7,12,18-四甲基-3,8-二乙基-13,17-丙酰基氨乙基联二硫基乙氨基甲酰乙基-29,34-二甲氧甲酰基]-卟啉[Co(Ⅱ)MPDTEP, V]. 对产物的结构行了表征, 分析了反应时间和反应温度对化合物[2,7,12,18-四甲基-3,8-二乙基-13,17-丙酰基氨乙基联二硫基乙氨基甲酰乙基-29,34-二甲氧甲酰基]-卟啉(MPDTEP, Ⅳ)产率的影响. 将化合物Ⅴ通过自组装修饰于金电极表面, 修饰的金电极通过傅里叶红外光谱(FTIR)和电化学方法进行表征, 研究了其对氧气的电催化还原效果.     

Sensitivity of circular dichroism of β-diketones to minute changes in the orientation of chromophores

Three optically active diastereomers of 3,8-di-t-butylspiro[4.4]nonane-1,6-dione have been prepared. Their c.d. spectra showed very different features to each other in spite of the same configuration at their spiro centers, showing the sensitivity of c.d. to minute changes in the orientation of chromophores.     

Generation of oxodiazonium ions 1. Synthesis of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxides

Methods for the synthesis of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxides, which include the reaction of 3-nitramino-4-(R-phenyl)furazans or their O-methyl derivatives with electrophilic agents, have been developed. Unsubstituted [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxide was synthesized from 3-nitramino-4-phenylfurazan upon the action of phosphorus anhydride or oleum, as well as from O-methyl derivative of 3-nitramino-4-phenylfurazan upon the action of H₂SO₄, MeSO₃H, CF₃CO₂H and BF₃·Et₂O, while 6-, 7-, 8-, and 9-nitro-substituted [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxides — from the corresponding 3-nitramino-4-(nitrophenyl)furazans upon the action of the H₂SO₄-HNO₃ nitrating mixture. A suggestion has been made that an oxodiazonium ion is formed in these reactions from nitramines or their O-methyl derivatives upon the action of electrophilic agents, which is further involved into the intra-molecular reaction of electrophilic aromatic substitution (S _EAr) with the aryl group. The structure of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-N-oxides was confirmed by ¹H, ¹³C, and ¹⁴N NMR spectra. Theoretical studies by the B3LYP/6-311G(d,p) method of combined molecular system (O-methylated 3-nitramino-4-phenylfurazan + [H₃SO₄]⁺) resulted in calculation of thermodynamic parameters of the sequence of cascade elementary reactions leading to the formation of [1,2,5]oxadiazolo[3,4-c]cinnoline 5-oxide.     

The Diffusion Coefficient of Lithium Ions into Highly Oriented Pyrolytic Graphite

The diffusion coefficient of lithium in graphite is an important parameter for the use of graphite because it relates to the ability of charge and discharge rate of lithium battery. It remains a problem that there are often obvious differences among the diffusion coefficients obtained using different methods, even in one paper^[1,2]. This difference may attribute to the complicate properties of intercalation process, as well as some uncertain parameters of the porous structure electrode. In order to measure the diffusion coefficient of lithium in carbon more precisely, a well crystallized material Highly Oriented Pyrolytic Graphite (HOPG) was used as the material of working electrode in this study.     

Neutral Cu4N12 and Ag4N12 metallacycles with a para-cyclophane framework assembled from copper(I) and silver(I) pyrazolates and pyridazine

Trinuclear copper(I) and silver(I) pyrazolates {[3,5-(CF3)2Pz]M}3 (M = Cu and Ag) react with pyridazine to give neutral, tetranuclear metallacycles with a para-cyclophane core whereas benzo[c]cinnoline fails to break the cyclic pyrazolate trimers under similar conditions, and affords a metalla-propellane featuring both two- and three-coordinate metal sites.     

Benzo[3,4]cyclobuta[1,2-b]thiophene

Tye synthesis of thieno[3,2-c]cinnoline is described; vapour phase thermolysis of this compound gives benzo[3,4]cyclobuta[1,2-b]thiophene.