Nesimi Uludag

Carbazole derivative synthesis and their electropolymerization

This review article investigates the hot topics by presenting the latest advances in carbazole and its derivative synthesis and their electropolymerization processes. The carbazole-based compounds are particularly attractive due to their important photochemical and thermal stability and good hole-transport ability. Conjugated monomers of carbazole derivatives and their polymers attract interest due to their suitability in a broad range of applications, such as biosensors, corrosion inhibition, photovoltaics, electroluminescent devices, field-effect transistors and supercapacitors, etc. This review article divides two main parts. One of them includes effects of electropolymerization parameters of carbazole and chemical polymerization of carbazole derivatives. In addition, copolymers and composites of carbazole derivatives were presented in the first part. In the second part, the application of polycarbazole and its derivatives was examined as biosensors, corrosion inhibition, supercapacitor, battery, fuel cell, solar cell, electropolymerization, light emitting diodes, and OLEDs.Graphcal abstractᅟ

Synthesis of 6-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl)-hexanoic acid, alternating copolymer formation, characterization and impedance evaluations

In this paper, 6-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl)-hexanoic acid (ThCzHa) comonomer was newly synthesized and characterized with Fourier transform infrared spectroscopy (FTIR) and 1H-NMR. The synthesized comonomer was electrochemically deposited onto carbon fiber microelectrode (CFME). An electrochemical impedance study on the prepared electrodes is reported. Poly(ThCzHa)/CFME is characterized by cyclic voltammetry (CV), Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR), scanning electron microscopy–energy dispersive X-ray analysis (SEM–EDX), and electrochemical impedance spectroscopy. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude, Bode-phase, and Admittance plots. The equivalent circuit model of R(Q(R(C(R(C(RW))))))(CR) was examined for polymer/electrolyte system. The effect of initial monomer concentration (0.5, 1.0 and 1.5 mM) on the formation of alternating copolymer is reported in 0.1 M sodium perchlorate/acetonitrile solution. The copolymer structure was also characterized by FTIR-ATR, SEM–EDX, and CV measurements. The highest low frequency capacitance (C LF = 5.2 mF cm−2), double layer capacitance (C dl=100  F cm−2) and maximum phase angle ∼82o at the frequency of 0.1 Hz were obtained for [ThCzHa]0 = 0.5 mM.

Concise Total Synthesis of 20-Deethyl-4-demethyldasycarpidone

The biological activities of these compounds make them of great pharmacological interest and have led to a sustained effort in the development of methods for their preparation; the tetracyclic ring system is believed to be primarily responsible for their analgesic, anti-inflammatory, bactericidal and central nervous system depressant properties. Considerable efforts have been devoted to the synthesis of Strychnos alkaloids such as uleine, dasycarpidone and tubifolidine. Previous reports from our group have Figure 1

New Route to 20-Deethyldasycarpidone by Ring-Closure with DDQ

The remarkable structural diversity of indole alkaloids as well as their significant biological activity have attracted much interest from synthetic organic chemists,1 providing inspiration and impetus for the development of novel synthetic strategies. Compounds such as dasycarpidone and 20-deethyl-4-demethyldasycapidone possess the tetracyclic ring system of the Strychnos indole alkaloids2,3 and one such alkaloids, 20-deethyldasycarpidone (8) is of great pharmaceutical interest. Several total synthesis of 8 have been reported previously.4,5 All routes for the construction of the 20-deethyldasycarpidone (8),6 (±)isodasycarpidone,7 dasycarpidone8 and 20-deethyl-4-demethyldasycarpidone9,10 start with 2-cyano-1,2,3,6-tetrahydropyridine9 or involve the reaction of indolemagnesium bromide with methyl 3-ethylisonicotinate N-oxide.11 The azocino[4,3-b]indole motif is also found as a key feature in other Strychnos, alkaloids, such as akuamicine, tubifolidine, etc.12–17,28–31 as well as in a new alkaloid valparicine isolated from the Kopsi species. It was decided to construct the azocino[4,3-b]indole skeleton of 8 and now report its synthesis in 21% overall yield from 1,2,3,4-tetrahydrocarbazol-1-one (1) (Scheme 1).

Synthesis of 5-(3,6-di(thiophene-2-yl)-9H- carbazole-9-yl)pentane-1-amine and Electrochemical Impedance Spectroscopy

In this article, 5-(3,6-di(thiophene-2-yl)-9H-carbazole-9-yl) pentane-1-amine, (ThCzPA) comonomer was newly synthesized and characterized by Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR) and 1H-NMR spectroscopy. ThCzPA was electrochemically deposited onto carbon fiber micro electrode (CFME). Poly(ThCzPA)/CFME is characterized by Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS). Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude and Bode-phase plots. The equivalent circuit model of R(Q(R(QR)(Q(RW))) was used for polymer-electrolyte system. The effect of monomer concentration (0.5, 1.0 and 1.5 mM) on the formation of alternating copolymer is reported in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The highest low frequency capacitance (CLF = 5.07 µF cm−2 for R(Q(R(QR)(Q(RW))) was obtained in the initial monomer concentration of 1.5 mM.

Facile synthesis of the azocino[4,3-b]indole framework of strychnopivotine and other Strychnos alkaloids

A new synthetic route to the 1,5-methanoazocino[4,3-b]indole is described. The aim of the present study is to provide a tetracyclic skeleton for the synthesis of pentacyclic Strychnos alkaloids (tubifolidine and strychnopivotine). Starting from a carbazole derivative, the ring closure was achieved by an intramolecular aldol reaction. The final product was obtained in 45% in the overall yield over 7 steps.

Poly(9H-Carbazole-9-Carbothioic Dithioperoxyanhydride) Formation and Capacitor Study

9H-Carbazole-9-carbothioic dithioperoxyanhydride (2CS2Cz) was chemically synthesized in our previous study. In this work, specific (Csp) and double layer capacitances (Cdl) of the electrocoated poly(9H-carbazole-9-carbothioic dithioperoxyanhydride) P(2CS2Cz) films were obtained on glassy carbon electrode (GCE). The polymers were characterized by cyclic voltammetry (CV), Fourier transform infrared reflectance-attenuated total reflection spectroscopy (FTIR-ATR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and electrochemical impedance spectroscopy (EIS). Polymer characterizations of FTIR-ATR, and SEM-EDX analysis were taken on carbon fiber microelectrodes (CFMEs). The initial monomer concentration of 2CS2Cz was taken as 0.25, 0.5, and 1.0 mM in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (CH3CN). The capacitance behavior of P(2CS2Cz)/GCE is shown by Nyquist, Bode-magnitude, Bode-phase, and Admittance plots relationship. The low frequency capacitance (CLF = 0.52 mF cm−2) and double layer capacitance (Cdl = 571 µF) were obtained for [2CS2Cz]0 = 0.25 mM and 1 mM, respectively. GRAPHICAL ABSTRACT

Supercapacitor Behavior of Poly(Carbazole-EDOT) Derivatives/Multi-Walled Carbon Nanotubes, Characterizations and Equivalent Circuit Model Evaluations

Three new different comonomers of carbazole-EDOT derivatives had been previously synthesized and characterized in detail. In this study, electroactive materials were electropolymerized onto multi-walled carbon nanotube (MWCNT) modified glassy carbon (GC) electrode in 0.1 M sodium dodecyl sulphate (SDS) solution. The electrochemical impedance spectroscopic results of Nyquist, and Bode-magnitude and Bode-phase plots show that polymers/MWCNT composites possess good capacitive characteristics. P(Com2)/MWCNT/GCE systems specific capacitance was up to Sc = 132.6 F g−1 at the scan rate of 70 mV s−1 from the area formula, Eq. (1). Furthermore, P(Com2)/MWCNT composite had very rapid charge/discharge ability with specific capacitance of Sc = 75.23 F g−1 at DC potential of 0.3 V from Nyquist plot, and Sc = 90.53 F g−1 at the scan rate of 60 mVs−1 from charge formula, Eq. (2), which is important practical advantage. In addition, such composite had a good cycling performance and a wide potential window. Long-term stability of the capacitor was also tested by CV, and the results indicated that, after 500 cycles, the specific capacitance was still at ∼100.0%, ∼89%, and ∼97.0% of the initial capacitance for P(Com1)/MWCNT, P(Com2)/MWCNT, and P(Com3)/MWCNT, respectively. An equivalent circuit model of Rs(C1(R1(Q(R2W))))(CGCRGC) was obtained to fit the experimental and theoretical data. Solution resistance (Rs) and resistance from GCE decrease gradually. However, capacitance of film (C1), constant phase element (Q), and n values increase for P(Com1), P(Com2), and P(Com3)/MWCNT, respectively. Therefore, more homogeneous and less rough surface composite film was obtained by addition of MWCNT in the composite material.

Copolymer formation of 4-vinylbenzyl-9H-carbazole-9-carbodithioate and ethylenedioxythiophene and capacitive behavior

In this study, first, a new monomer of 4-vinylbenzyl 9H-carbazole-9-carbodithioate (VBzCzCT) was chemically synthesized and characterized using Fourier transform infrared (FTIR) reflectance, proton nuclear magnetic resonance (1H NMR), and carbon nuclear magnetic resonance (13C NMR) spectroscopies. Second, VBzCzCT and 3,4-ethylenedioxythiophene (EDOT) monomers were electrocopolymerized (VBzCzCT-co-EDOT) in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (CH3CN) on glassy carbon electrode (GCE) using cyclic voltammetry (CV). Third, the best deposition conditions on the electroactivity of the modified homopolymers and copolymer were studied and characterized using different techniques such as CV, FTIR-attenuated total reflectance, scanning electron microscopy–energy dispersion x-ray analysis, and electrochemical impedance spectroscopy (EIS) analysis. The specific capacitance (C sp) of poly(VBzCzCT) (P(VBzCzCT)) was obtained as 20.5 mF cm−2. However, the C sp of P(VBzCzCT-co-EDOT)/GCE was obtained as 45.5 mF cm−2. There is an important improvement in the capacitance value of copolymer formation. The C sp value increases more than twice from P(VBzCzCT) to copolymer. The highest double layer capacitance (C dl = approximately 27.5 mF cm−2) was obtained for P(VBzCzCT-co-EDOT) and P(EDOT) compared with P(VBzCzCT) (C dl = approximately 8.28 mF cm−2. Finally, simulation graphs of Nyquist, Bode-magnitude, and Bode-phase plots were given for homopolymers and copolymer for the electrical equivalent circuit model of R s(Q 1(R 1(C 1(R 2(C 2(R 3 · W))))))(C 3 R 4). The EIS results of P(VBzCzCT), P(EDOT), and P(VBzCzCT-co-EDOT) might be studied as promising active electrode materials for (super)capacitor evaluations.

Circuit Model Evaluation of Poly(methyl pyrrole-co-2-(9H-carbazole-9-yl)ethyl methacrylate) on Carbon Fiber

Methyl pyrrole (N-MPy) and 2-(9H-carbazole-9-yl) ethyl methacrylate (CzEMA) monomers were electrocopolymerized on carbon fiber microelectrode (CFME) as an active electrode material. The electropolymerization of monomers was studied in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (ACN) solution. The detailed characterization of the resulting electrocoated poly(N-MPy-co-CzEMA)/CFME thin films was studied by various techniques, i.e., cyclic voltammetry (CV), Scanning electron microscopy – Energy Dispersive X-ray analysis (SEM-EDX), and Electrochemical impedance spectroscopy (EIS). The effects of monomer mole fractions (mole fraction, XCzEMA = nCzEMA/nMPy + nCzEMA) (0.5, 0.66, 0.75, 0.83 and 0.91) during the preparation of modified electrodes were examined by EIS. Capacitive behaviors of modified CFMEs were defined via Nyquist, Bode-magnitude, Bode-phase and Capacitance plots. Circuit model of R(Q(R(C(R(C(RW))))))(CR) was suggested to fit the theoretical and experimental values. The lowest low frequency capacitance value and total charge (Q = 112.9 mC) during electrodeposition of polymer thin film by CV method in the mole fraction of XCzEMA = 0.75 (CLF = ∼27.2 mF cm−2). However, the highest double layer capacitance of polymer/electrolyte system (C1 = 25.4 mF cm−2; C2 = 159.1 mF cm−2; C3 = 4.54 mF cm−2) was obtained in the same mole fraction.