Carbazole-linked porphyrin dimers for organic light emitting diodes: synthesis and initial photophysical studies

Carbazole-functionalized cobalt(ii) porphyrin axially bonded with C60/C70 derivatives: synthesis and characterization

Depending on the structure of the fullero[60]/[70]pyrrolidine, the carbazole-functionalized cobalt(ii) porphyrin forms donor–acceptor systems of different compositions.

Robust therapeutic potential of carbazole-triazine hybrids as a new class of urease inhibitors: A distinctive combination of nitrogen-containing heterocycles

The inhibition of urease enzyme is very important as it plays a key role in the treatment of several urinary and gastrointestinal tract infections. This enzyme provides a suitable environment for Helicobacter pylori at the low pH of the stomach, a causative agent of gastric and peptic ulcer that may lead to cancer. In agriculture, the high urease content causes environmental and economic problems. In this pursuit, given the well-established importance of integrated pharmacophores in medicinal chemistry and to explore new inhibitors of urease featuring two distinct heterocyclic functionalities, we herein report a facile synthesis of carbazole-triazine hybrids (3a-j). These new propeller-shaped chemical scaffolds were evaluated for their urease inhibitory potential in order to identify suitable leads. The initial structure-activity survey work guided through in vitro bioactivity results recognized 3e and 3f as new starting point hits incorporating bulky iodo (3e) and strong electron-withdrawing nitro (3f) groups at the para-position of aryl amine component. The potent compounds (3e &3f) exhibited the highest activity with IC₅₀ values of 5.6 and 6.7 µM, respectively. In the molecular docking analysis, these compounds depicted excellent binding interactions with the active site residues. The key interactions observed include hydrogen bonding, π-π interactions, π-cation and nickel atom coordination to the triazine nitrogen of both inhibitors.

Synthetic aspects of carbazole containing porphyrins and porphyrinoids

Porphyrins are tetrapyrrolic aromatic macrocycles and ubiquitous in nature. They are excellent dyes with strong absorption in the visible region (400–700 nm) and they exhibit decent fluorescence in the red region (620–900 nm). Carbazole is a nitrogen-containing electron rich aromatic heterocycle which can be linked to porphyrins and other chromophores. This review provides an overview of the different synthetic strategies that have been employed to prepare carbazole-substituted porphyrins and carbazole-fused porphyrinoids and similar systems. It also shows that how the substitution of carbazole occurs on the porphyrin core can alter its optical and electronic features. Introduction of carbazole moieties in the porphyrin ring resulted in fused porphyrinoids with changed aromaticity and significantly altered electronic features of the molecules.

Donor–acceptor type A2B2porphyrins: synthesis, energy transfer, computational and electrochemical studies

Synthesis, photophysical, electrochemical and DFT studies of donor–acceptor type A₂B₂porphyrins and their Zn(ii) and Pd(ii) complexes have been described.

New carbazole appended subporphyrin displaying intramolecular charge transfer and solid state fluorescence

A new subporphyrin namely, hydroxo-5,10,15-tri([Formula: see text]-propyl-3-carbazolyl)subporphyri natoboron(III) 6 has been synthesized via the reported litreture procedure by the condensation of pyridine-tri-[Formula: see text]-pyrrolylborane with 9-propyl-9H-carbazole-3-carbaldehyde. Its porphyrin analog [Formula: see text]. 5,10,15,20-tetra([Formula: see text]-propyl-3-carbazolyl)porphyrin has also been isolated from the reaction mixture, formed due to scrambling process and complexed with Zn(II). Photophysical properties of both subporphyrin and Zn(II)porphyrin have been studied in detail to confirm the intramolecular charge transfer process in subporphyrin analog. In addition, the ring contracted congener 6 also displays solid state fluorescence.

Predicting larger absorption cross-section in porphyrin dyes using DFT calculations

Porphyrin macrocycles play an important role in designing of fluorophores with superior light harvesting properties similar to that of antennas in biological systems. In this paper, new Zn(II)porphyrin dyes were investigated to improve the performance of the YD2-o-C8 using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Effects of various substituted and anchoring groups on basic porphine and Zn(II)porphyrin derivatives were systematically studied at the B3LYP/LanL2DZ level. The absorption spectra of Zn(II)porphyrin derivatives bearing one, two and four anchoring groups in the meso-positions were also studied. The calculations showed that a molecule [5, 10, 15, 20-(4-carboxyphenylethynyl)porphyrinato]Zn(II) have large absorption cross-section than available in the existing porphyrin dyes. The results of these calculations would open up enormous possibilities to develop porphyrin dyes characterized by high absorption cross-section for various light harvesting applications.

Benefits of using BODIPY–porphyrin dyads for developing deep-red lighting sources

The syntheses, as well as the photophysical and electrochemical characterization, of two novel BODIPY–porphyrin dyads and their first application in lighting schemes are provided.

Synthesis and Characterization of Carbazole-Linked Porphyrin Tweezers

Herein the synthesis, spectroscopic characterization, two-photon absorption and electrochemical properties of 3,6-disubstituted carbazole tweezers is reported. A dimer resulting from a Glaser homocoupling was isolated during a Sonogashira coupling reaction between a diethynyl-carbazole spacer and a 5-bromo-triarylporphyrin and the properties of this original compound were compared with the 3,6-disubstituted carbazole bisporphyrin tweezers. The dyads reported herein present a two-photon absorption maximum at 920 nm with two-photon absorption cross-section in the 1200 GM range. Despite a strong linear absorption in the Soret region and moderate fluorescence quantum yield, they both lead to a high brightness reaching 30 000 M(-1)  cm(-1) .

Carbazole–corrole and carbazole–prophyrin dyads: synthesis, fluorescence and electrochemical studies

Carbazole–corrole and carbazole–porphyrin dyads were synthesized, and fluorescence studies indicated efficient energy transfer from carbazole-donor to corrole/porphyrin acceptor in the dyads.

STRUCTURES AND SPECTROSCOPIC PROPERTIES OF THREE AROMATIC HETEROCYCLIC DYE PHOTOSENSITIZERS

The ground-state structures and absorption spectra of three dyes, carbazole, phenothiazine and diphenylamine, were studied by the density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The strong absorption peak, electron transition as well as the energy levels of molecular orbitals were obtained and compared in the gas and solvent phase. Furthermore, we further calculated the effect of the expanding conjugated bridge on the absorption spectra and the energy levels of molecular orbitals. Visualized method of charge difference density (CDD) was used to show the direction of charge transfer in the molecules of interest during photo-excitation.