N-alkyl Carbazole Research Articles

Disulfide-linked symmetric N-alkyl carbazole derivative as a new electroactive monomer for electrochromic applications

In this study, we reported a novel and an unusual method for the preparation of the disulfide-linked symmetrical carbazole derivative and investigated the electrical and optical properties of crosslinked conductive polymer obtained as a result of its electropolymerization. The disulfide-linked N-alkyl substituted carbazole monomers are comparatively polymerized in different solvents. It has been found that the conductive polymer obtained in Boron trifluoride diethyl etherate (BFEE) has the high optical contrast and stability compared to other N-alkyl substituted carbazoles in literature.

N-alkyl carbazole derivatives as new tools for Alzheimer's disease: preliminary studies.

Alzheimer’s disease (AD) is a progressive and age-related neurodegenerative disorder affecting brain cells and is the most common form of “dementia”, because of the cognitive detriment which takes place. Neuronal disruption represents its major feature, due to the cytosolic accumulation of amyloid β-peptide (Aβ) which leads to senile plaques formation and intracellular neurofibrillary tangles. Many studies have focused on the design and therapeutic use of new molecules able to inhibit Aβ aggregation. In this context, we evaluated the ability of two recently synthesized series of N-alkyl carbazole derivatives to increase the Aβ soluble forms, through molecular docking simulations and in vitro experiments. Our data evidenced that two carbazole derivatives, the most active, adopt distinct binding modes involving key residues for Aβ fibrillization. They exhibit a good interfering activity on Aβ aggregation in mouse (N2a) cells, stably expressing wild-type human amyloid precursor protein (APP) 695. These preliminary results are promising and we are confident that the N-alkyl carbazole derivatives may encourage next future studies needed for enlarging the knowledge about the AD disease approach.

Investigation of thermal instability of benzoyl peroxide in the presence of carbazole and its derivatives

Benzoyl peroxide (BPO), a commonly used organic peroxide, has caused many catastrophes. The thermal characteristics of BPO mixed with carbazole and its derivatives are studied under non-isothermal conditions using differential scanning calorimetry (DSC). The kinetic parameters are obtained from analysis of the DSC curves by the Kissinger and Ozawa methods. Results indicated that when BPO is mixed with carbazole and N-alkyl carbazole, the hazard increased with lower activity energy (Ea) and exothermic peak (Tp). In the presence of N-alkyl substituted carbazole, the Tp for the decomposition of BPO is reduced to 75 °C, the decomposition procedure becomes more complex than that of pure BPO, and the exothermic decomposition peak in the DSC trace splits into two. In the presence of a cationic cyclopentadinyl iron carbazole complex, the decomposition hazard of BPO does not increase.

Novel Photoactive Fluorene-Based Terpolymers Incorporating Carbazole for Photovoltaic Application

A series of novel photoactive conjugated terpolymers based on N-alkyl carbazole, 9,9-didecylfluorene, and bis(thienyl)benzothiadiazole were synthesized by the Pd-catalyzed Suzuki polymerization method with various molar ratios of the carbazole derivatives. Electron-deficient benzothiadiazole and electron-rich carbazole moieties were incorporated into the polymer backbone to obtain the broad absorption spectrum and to improve the hole-transporting characteristics, respectively. The polymer solar cell (PSC) was fabricated with a layered structure of ITO/PEDOT: PSS/polymer:C71-PCBM (1:3)/LiF/Al. The best performance of PSC was obtained at P1:C71-PCBM whose reaches a power conversion efficiency (PCE) of 2.62%, with a short circuit current density (J(SC)) of 8.61 mA/cm2, an open circuit voltage (V(OC)) of 0.82 V, and a fill factor (FF) of 0.37 under AM 1.5 G irradiation (100 mW/cm2).

Synthesis and Characterization of Conjugated Low Band-Gap Terpolymers Incorporating Carbazole for Photovoltaic Application

A series of photoactive conjugated low band-gap copolymer (CPSB) and terpolyemrs (TPSBCz-n, n = 1 to 4) based on N-alkyl carbazole, 4,4'-dialkyl dithienosilole, and bezothiadiazole were synthesized. The copolymer and terpolymers were built with the fraction of the carbazole unit varied for 0, 2.5, 5, 10 and 25 mol%. Among the mixtures, the composition of 25 wt% of terpolymer bearing 10 mol.% of the carbazole unit, TPSBCz-3, and 75 wt% of C71-PCBM found a power conversion efficiency of 0.86% with a open-circuit voltage of 0.59 V, the short-circuit current of 4.85 mA and fill factor of 0.30 under AM 1.5 spectral illumination. Our findings suggest that terpolymer bearing low concentration of carbazole lead to a high power conversion efficiency with improved the short-circuit current due to hole mobility enhancement effect of carbazole unit.

Synthesis and optical properties of π-conjugated polymers composed of diester-substituted bithiophene and dibenzothiophene or carbazole

Novel π-conjugated polymers composed of diester-subsituted bithiophene and dibenzothiophene (PDBT-DEBT) or N-alkyl carbazole (PCz-DEBT) were prepared via the Stille cross-coupling polymerization using Pd(0) catalyst. The structures of obtained polymers were confirmed by 1H NMR and IR spectroscopies. Optical properties of the polymers were investigated by UV–vis and photoluminescence spectroscopies. The photoluminescence spectra of the polymers showed strong emission peaks in the green region.

Soluble blue light emitting pyridine-containing polymers prepared by oxidative-coupling copolymerization

Novel polymers containing pyridine moieties in main chains have been prepared by facile oxidative-coupling co-polymerization of pyridine N-oxide with N-alkyl carbazole and fluorene as the precursor polymers, which were reduced to the pyridine-containing polymers respectively. The polymers were characterized by FT-IR, 1H NMR, UV–Vis, X-ray, thermo-gravimetric analysis, and fluorescence spectroscopy. The pyridine-containing polymers good solubility in convenient organic solvents, high thermal stability with the onset decomposition temperature above 310 °C. The electrochemical behaviors of the polymers were investigated by cyclic voltammetry; the HOMO and LUMO energy level of the polymers were estimated from the electrochemistry and UV–Vis spectroscopy. The fluorescence spectra of the pyridine-containing polymers display blue light emitting properties in both solution and solid-state film.

Synthesis and Fluorescence of Pyridine-N-alkyl carbazole Copolymer Prepared by Oxidative-coupling Reaction

Abstract A new kind of copolymers incorporated pyridine and N-alkyl carbazole alternatively into main chain has been prepared by oxidative-coupling copolymerization. The polymers are thermostable, highly soluble, and processable. The fluorescence spectra of the polymers display blue light emitting properties.

Permeability of lipid bilayers to methylmercuric chloride: Quantification by fluorescence quenching of a carbazole-labeled phospholipid

We investigated the permeabilities of lipid bilayers to the neurotoxin methylmercuric chloride (MMC). This mercurial is an efficient collisional quencher of the fluorescence of N-alkyl carbazole derivatives. Quenching of the fluorescence of β-(3-(9-carbazole)-propionyl-L-α-phosphatidylcholine (CPA-PC) in vesicles of dimyristoyl phosphatidylcholine and of dioleoyl phosphatidylcholine reveal rapid diffusion of MMC in the alkyl side chain regions of these bilayers. By a combination of (1) the lipid concentration dependence of the apparent quenching constants, (2) the solubility of MMC in concentrated lipid dispersions and (3) the 270 MHz proton magnetic resonance of methylmercury in the presence of lipid bilayers we conclude that the lipid-water partition coefficient of this mercurial is less than or equal to two. Using the fluorescence quenching and the partitioning data we estimate the diffusion coefficient of MMC in these bilayers to range from 0.13 to 0.31 × 10 −5 cm 2/sec, or 20–47% of its diffusion coefficient in ethanol. These data indicate that lipid bilayers do not pose a significant permeability barrier to the diffusional transport of MMC.