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A novel carbazole compound, named 1-(9-ethyl-9H-carbazol-3-yl)-3-phenylurea (Cpu) was synthesized and its binding properties with protease enzymes (pepsin and trypsin) has been examined by steady-state fluorescence measurements, UV/vis absorption, infrared (FT-IR) and circular dicroism (CD) spectroscopies and also computational methods. The fluorescence experimental results indicated that the quenching mechanism of enzyme by Cpu is static process. The thermodynamic parameters (both negative ΔH/ΔS) and molecular docking results suggested that the binding of Cpu to pepsin/trypsin were driven by hydrogen bonds and van der Waals forces. Based on Förster's theory, the binding distance (r) between pepsin/trypsin and Cpu was calculated to be 3.072/2.784 nm, which implies that non-radiative energy transfer occurs from enzyme to Cpu. Furthermore, absorption, CD, and FT-IR spectral analysis provided an evidence that the presence of Cpu induced notable changes in the secondary structures and microenvironmental of both pepsin and trypsin, supporting its significant influence on these enzymes., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The importance of indigo dyes is constantly increasing with the evolution of novel textile materials and photochromic material technologies. The aim of this review article is to provide a comprehensive overview of the development of photochromic indigo derivatives from the first report on the photochromic N,N' -diacetylindigo in 1954 until now. We begin with the list of historical milestones in the development of photochromic indigo derivatives. Further, we provide a brief description of the synthetic procedures utilised to obtain indigo and its derivatives, outline the structural peculiarities, photophysical and photochemical properties of indigo and proceed with the detailed discussion of the photochromic indigo derivatives. Finally, we highlight the photochromism of the structural isomers of indigo (isoindigo and indirubin) and provide an overview of prospective applications of indigo photoswitches., (Copyright © 2024, Kaplan et al.)

This study reports the synthesis of two novel thiazolylazo dyes (4 and 5) bearing coumarin-thiophene moiety. UV-Vis spectroscopy was used to investigate the photophysical properties of 4 and 5 in different solvents. The dyes displayed good potential for hydroxide sensing in different mediums. The reversibility was also studied, and it was found that 4 and 5 could be reverted to their original state by adding acid. Furthermore, the acidochromic properties were studied in protic and aprotic media. Both dyes displayed a good acidochromic response in DCM. Moreover, 4 and 5 were investigated for pH sensing, and it was found that both compounds displayed changes in absorption spectra in a basic media. The theoretical calculations were carried out to investigate the deprotonation and protonation mechanisms using density functional theory (DFT). The thermal properties of the dyes were investigated using thermogravimetric analysis (TGA). The results showed good thermal stability up to around 200 °C., (© 2023. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Cyanide anion has wide use in industrial areas; however, it has a high toxic effect on the environment as waste. Moreover, plant seeds contain cyanide that is often consumed by human beings. Therefore, many studies are carried out to determine cyanide. Especially, optical sensors showing colorimetric and fluorimetric changes have been of considerable interest due to their easy, cheap, and fast responses. This review discusses recent developments in the colorimetric and fluorimetric detection of cyanide by nucleophilic addition to different types of receptors via the chemodosimeter approach. The sensitivity and selectivity of the sensors have been reviewed for changes in absorption and fluorescence, naked-eye detection, real sample application, and detection limits when interacting with cyanide., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

This paper describes indigo chemistry and its brief scientific history beginning with the first characterization and chemical synthesis of indigo via various precursors such as isatin, cinnamic acid, 2-nitrobenzaldehyde, anthranilic acid, N-phenylglycine, aniline, and indole. Furthermore, alternative methods such as eco-friendly microbial synthesis of indigo using a variety of enzymes are reported: Cytochrome P450 monooxygenases, flavin-containing monooxygenases, and unspecific peroxygenases. Subsequently, the application of indigo in the denim industry, reduction methods (chemical, electrochemical, enzymatic and catalytic) and dyeing methods (all parameters in dyeing, ring dye) are discussed. In addition, the main reason for the use of indigo in the denim industry is briefly explained., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Neurotransmitters are chemical compounds released by neurons acting as messengers that transmit signals to other neurons, called postsynaptic neurons, or other types of cells. These neurotransmitters play a crucial role in the nervous system, and abnormalities in their levels have been associated with physical, psychotic, and neurodegenerative diseases such as Alzheimer's, Parkinson's, dementia, addiction, depression, and schizophrenia. This makes it necessary to develop sensitive and reliable techniques for their detection and monitoring in order to screen diseases. Meanwhile, neurotransmitters' detection remains a challenge and continues to attract considerable attention. Fluorescent and colorimetric organic probes were and still efficient tools for rapid, selective and low-cost detection of a large scale of analytes. Neurotransmitters can interact with the sensing molecule leading to the formation of complexes or new molecules displaying photophysical properties different from the starting fluorophore or/and chromophore and thus through different sensing mechanisms. Diverse applications of the sensors like live cell imaging are being reported. This review is a collection of recent development in the design of new organic receptors utilized for the detection of neurotransmitters including monoamines (catecholamines, serotonin and histamine), amino acids (glutamate, aspartate and glycine), gasotransmitters, and acetylcholine., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

A new cationic indolium based styryl dye (Ci) as a fluorescent probe was synthesized and its anions selectivity/sensitivity properties/molecular interactions with protease enzymes (pepsin/trypsin) and ctDNA has been studied by spectroscopic and computational methods. The fluorescence measurements at different temperatures indicated that quenching mechanism of enzymes by Ci was static. ΔH and ΔS data pointed out electrostatic/hydrophobic interactions with pepsin, and also hydrogen bonds/van der Waals forces with trypsin of Ci. According to Förster's non-radiative energy transfer, binding distances (r) were calculated as 3.53/3.27 nm for pepsin/trypsin. It was also investigated that groove binding is effective in interaction with ctDNA. The results were supported with molecular docking analyzes which have same tendency. Ci has been demonstrated hypsochromic effect with a decrease in polarity of solvents and it showed highly selective colorimetric and fluorometric sensing behavior for cyanide in organic solvent and in aqueous solution. 1 H NMR titration was performed to examine the interaction mechanism between Ci and cyanide. The LOD values of cyanide ion were reported as 4.87 × 10 -9  M and 9.70 × 10 -7  M in DMSO and DMSO/H 2 O binary mixture, respectively. In addition, sensitivity of Ci as a chemosensor to cyanide was investigated in bitter almond samples., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In this study, six new 1,4-disubstituted bis-1,2,3-triazole compounds, N,N'-(1,2-phenylene)bis(2-(4-R-1H-1,2,3-triazol-1-yl)acetamide), were synthesized with high yield (88-96 %) by using click chemistry and their molecular structures were characterized by using NMR, FT-IR, HRMS and elemental analysis techniques. Previous studies suggest anti-inflammatory and analgesic activities for different 1,2,3-triazole derivatives and in the light of those studies we aimed to examine these novel derivatives immunomodulatory activities on the mammalian macrophages. Pro-inflammatory cytokines (TNF, IL6, GMCSF and IL12p40) secretion levels were tested in the presence of bis-1,2,3-triazole compounds when the macrophages were activated with LPS. These new derivatives were able to suppress the production of these cytokines at different levels. Intracellular phophorylated PI3K protein levels were measured due to its prominent role in inflammatory reactions. Our flow cytometry analysis results suggested that some of these compounds were partially effective through PI3K pathway. In different inflammatory and autoimmune disease settings these novel 1,2,3-triazole derivatives can be utilized as non-steroid based anti-inflammatory drug candidates., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

In this work, Combining coumarin and thiazole with 3-tertiary butyl salicylaldehyde into in a single molecule, new Schiff base (CTS), and its metal complexes with palladium and platinum were synthesized and characterized by using well-known spectroscopic techniques such as 1 H-NMR, 13 C-NMR, FT-IR and LC-MS. And also, the formation of these complexes were confirmed by magnetic moment and conductivity measurements. The photophysical properties of CTS were studied and it was observed that the Schiff base has a sensitivity to CN - , F - , and AcO - anions. The quantum chemical calculations based on density functional theory (DFT) were done for explaining some experimental, structural, and spectroscopic data of the dyes. Also, to evaluate the binding interactions between the ligand (CTS) and its metal complexes and enzymes, molecular docking studies were performed and all the compounds tested to determine its inhibition potential against the cholinesterase (AChE and BChE) and pancreatic cholesterol esterase (CEase) enzymes. Both in vitro and in silico the results showed that all of the compounds could act as potent inhibitors of AChE, BChE, and CEase. The Pt (II) complex showed the most potent inhibitory property against all of the enzymes with IC 50 values of 12 µM for AChE, 23 µM for BChE, and 21 µM for CEase.Communicated by Ramaswamy H. Sarma.

The development of fluorescent dyes capable of selective recognition of G-quadruplexes is essential for studying its localization and biological functions. However, considering the G-quadruplex topologies may vary significantly, the synthesis of compounds showing both selectivity and strong fluorescence properties still remains a great challenge. Recently we have developed fluorene/fluorenone derivatives with structure-specific binding towards dsRNA, indicating its potential for structure-selective ligands. Herein, we report the synthesis of novel fluorene/fluorenone derivatives and their selectivity towards various DNA structures, particularly G-quadruplexes, two of which showed strong affinity to the proto-oncogene c-myc promoter G-quadruplex., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A series of D-π-A chromophores based on allylidenemalononitrile electron-withdrawing group was designed. The influence of the amino-electron-donating group on the photophysical properties was studied. These compounds, highly thermally stable, exhibit orange-red emission in solution and in solid state. The experimental results have been rationalized by theoretical DFT calculations. The second order nonlinear optical properties were also studied using the electric field induced second harmonic generation (EFISH) method., Competing Interests: Declaration of Competing Interest The authors declared that there is no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this work, we presented the synthesis and investigation of binding properties of the new morpholine containing 3-amido-9-ethylcarbazole derivative (CMR) to calf thymus DNA (ctDNA) and human serum albumin (HSA) by fluorescence spectroscopy, UV absorption spectroscopy and molecular docking method. A decrease in Stern-Volmer constants was obtained with increase in temperature; it shows that static quenching mechanism leads to formation of new CMR-DNA/HSA complexes, which have hydrophobic interaction as the predominant role in the binding modes. Also, binding properties of DNA were investigated with competition assays on two probes (EB and H33258) by absorption, ionic strength and iodide ion quenching methods. The results suggested that CMR entered into the minor groove binding on the A-T region of DNA. The spectral data further confirmed by molecular docking which elicited that CMR complexes have similar interaction and conformation trends to each target, DNA and HSA. The experimental and computational results show that CMR has been classified as a promising molecule in drug designing of other carbazole derivatives.Communicated by Ramaswamy H. Sarma.

Herein we report the synthesis and characterization of a new series of styryl-based push-pull dyes containing a free amino group and their Schiff base derivatives. The dyes include the dicyanomethylene group as an acceptor and different para -substituted alkylamines as donors. Morever as a proton-sensitive group a pyridin-2-yl substituent was attached to the para -position of the phenyl moiety in both series of compounds. The photophysical properties of the dyes were examined in various solvents with different polarities and showed absorption in the visible region and green-red emission with low quantum yields. The absorption and the emission maxima were shifted bathocromically by increasing the solvent's polarity. However, there was no correlation with the polarity parameters of the solvents. The pH-sensitive properties of all prepared Schiff bases were examined against TBAOH in DMSO, via deprotonation of the OH group in the salicylidene moiety and their reverse protonation was also investigated using TFA. The Schiff bases exhibited a bathochromic shift upon the addition of TBAOH to their solutions in DMSO. Therefore, they showed potential to be utilized as colorimetric and luminescence pH sensors. The second-order nonlinear optical (NLO) responses of the dyes were measured by the electric field-induced second harmonic (EFISH) generation method. The highest μβ values were obtained for the dyes bearing the julolidine donor as 1430 × 10 -48 esu (for free amino derivative) and 1950 × 10 -48 esu (for Schiff base derivative), respectively. The structural and electronic properties of the dyes as well as their NLO properties were further studied using DFT calculations. The thermal stabilities of all dyes were evaluated by thermogravimetric analysis (TGA). The TGA data showed that all dyes were thermally stable up to 250 °C., (Copyright © 2020, Putra et al.; licensee Beilstein-Institut.)

The interaction mechanisms of two ethidium derivatives, 3,8-dibenzoylamino-5-ethyl-6-phenylphenantridinium chloride (E2) and 3,8-diphenylacetylamino-5-ethyl-6-phenylphenantridinium chloride (E3) with serum albumins (BSA and HSA) have been investigated by a combined experimental and computational approach. Fluorescence quenching and UV-vis results revealed that the interaction of derivatives with albumins resulted in formation of ground-state complexes and the obtained Stern-Volmer quenching constants designate the presence of a static component in the quenching mechanisms. Thermodynamic parameters (ΔH and ΔS values) point out the ionic interactions play the major role in E2-BSA, E2-HSA and E3-HSA complexes. The van der Waals interactions are dominant forces in E3-BSA complex. Moreover, the obtained results in this study were supported with computational analyzes which have same tendency.

An improved microwave-induced synthesis of five ethidium derivatives (Ethidium derivatives, 2a-d) is presented. As the derivatives 2a-d have been proposed previously to be telomerase inhibitors, the binding interactions of these ethidium derivatives with G-quadruplex DNA were evaluated by means of photometric and fluorimetric titration, thermal DNA denaturation, CD and 1 H NMR spectroscopy. In particular, the compound bearing 3,8-bis(pyrrolidin-1-yl)propanamido substituent 2a exhibits high selectivity for G-quadruplex DNA relative to duplex DNA., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A new coumarin-thiazole based Schiff base (Ligand, L) and its Pd(II), Pt(II) complexes; ([Pd(L) 2 ] and [Pt(L) 2 ]), were synthesized and characterized using spectrophotometric techniques (NMR, IR, UV-vis, LC-MS), magnetic moment, and conductivity measurements. A single crystal X-ray analysis for only L was done. The crystals of L have monoclinic crystal system and P21/c space group. To gain insight into the structure of L and its complexes, we used density functional theory (DFT) method to optimize the molecules. The photophysical properties changes were observed after deprotonation of L with CN - via intermolecular charge transfer (ICT). Additionally, as the sensor is a colorimetric and fluorimetric cyanide probe containing active sites such as coumarin-thiazole and imine (CH=N), it showed fast color change from yellow to deep red in the visible region, and yellow fluorescence after CN - addition to the imine bond, in DMSO. The reaction mechanisms of L with CN - , F - and AcO - ions were evaluated using 1 H NMR shifts. The results showed that, the reaction of L with CN - ion was due to the deprotonation and addition mechanisms at the same time. The anti-cancer activity of L and its Pd(II) and Pt(II) complexes were evaluated in vitro using MTT assay on the human cancer lines MCF-7 (human breast adenocarcinoma), LS174T (human colon carcinoma), and LNCAP (human prostate adenocarcinoma). The anti-cancer effects of L and its complexes, on human cells, were determined by comparing the half maximal inhibitory concentration (IC 50 ) values. The activity results showed that, the Pd(II) complex of L has higher anti-tumor effect than L and its Pt(II) complex against the tested human breast adenocarcinoma (MCF-7), human prostate adenocarcinoma (LNCAP), and human colon carcinoma (LS174T) cell lines., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The binding interaction between two dicationic styrylimidazo[1,2-a]pyridinium dyes and human serum albumin (HSA) was investigated at physiological conditions using fluorescence, UV-vis absorption, and circular dichroism (CD) spectroscopies. Analysis of the fluorescence titration data at different temperatures suggested that the fluorescence quenching mechanism of HSA by these dyes was static. The calculated thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that hydrogen bonding and van der Waals forces played a major role in the formation of the dye-HSA complex. Binding distances (r) between dyes and HSA were calculated according to Förster's non-radiative energy transfer theory. Studies of conformational changes of HSA using CD measurements indicate that the α-helical content of the protein decreased upon binding of the dyes. Copyright © 2016 John Wiley & Sons, Ltd., (Copyright © 2016 John Wiley & Sons, Ltd.)

This work highlights the literature of one of the most valuable moieties in the field of organic chemistry. In this review, the chemistry of tetronic acid as a simple precursor to privileged heterocyclic motifs is described. The synthetic procedures of different fused heterocycles incorporating a furan moiety are described. Fused heterocycles are classified as bicyclic, tricyclic, tetracyclic and spiro-fused pyran derivatives.

This study reports the preparation and investigation of the modes of binding of the two symmetric 3,6-diaminoacridine derivatives obtained from proflavine, which are 3,6-diphenoxycarbonyl aminoacridine and 3,6-diethoxycarbonyl aminoacridine to human serum albumin (HSA). The interaction of HSA with the derivatives was investigated using fluorescence quenching and ultraviolet-visible absorption spectra at pH 7.2 and different temperatures. The results suggest that the derivatives used can interact strongly with HSA and are the formation of HSA-derivative complexes and hydrophobic interactions as the predominant intermolecular forces in stabilizing for each complex. The Stern-Volmer quenching constants, binding constants, binding sites and corresponding thermodynamic parameters ΔH, ΔS and ΔG were calculated at different temperatures. The binding distance (r) ~ 3 nm between the donor (HSA) and acceptors (3,6-diethoxycarbonyl aminoacridine, 3,6-diphenoxycarbonyl aminoacridine and proflavine) was obtained according to Förster's non-radiative energy transfer theory. Moreover, the limit of detection and limit of quantification of derivatives were calculated in the presence of albumin., (Copyright © 2014 John Wiley & Sons, Ltd.)

In this study, the synthesis of four new phenylazo indole dyes (dye 1-4) were carried out by diazotization of 4-aminoacetophenone and coupling with various 2- and 1,2-disubstituted indole derivatives. The dyes were characterized by UV-vis, FT-IR, (1)H NMR, HRMS and X-ray single crystal diffraction methods. Azo-hydrazone tautomeric bahavior of the dyes in different solvents (DMSO, methanol, acetic acid and chloroform) was investigated by using (1)H NMR and UV-vis results. The experimental results were compared with the corresponding calculated values. The results of experimental data and theoretical calculations showed that the azo tautomer is more stable than hydrazone tautomer. In addition to this, the antimicrobial activity of the dyes was also evaluated., (Published by Elsevier B.V.)

In the title mol-ecule, C(16)H(15)N(3), the indole ring system is planar within 0.021 (3) Å and the phenyl ring is inclined to this plane by 17.32 (14)°. π-π contacts involving the pyrrole rings of inversion-related indole units [centroid-centroid distance = 3.5187 (17) Å] stabilize the crystal structure.

In this paper, we reported the syntheses and investigation of the modes of binding to DNA of the two new ethidium derivatives containing benzoyl and phenylacetyl groups of both amines at 3-and 8- positions. The interactions between calf thymus DNA (ct-DNA) and the two derivatives, 3,8-dibenzoylamino-5-ethyl-6-phenylphenantridinium cloride (E2) and 3,8-diphenylacetylamino-5-ethyl-6-phenylphenantridinium chloride (E3), were investigated by fluorescence quenching spectra and UV-vis absorption spectra. The Stern-Volmer quenching constants, binding constants, binding sites and the corresponding thermodynamic parameters DeltaH, DeltaS and DeltaG were calculated at different temperatures. The results indicated the formation of E2 and E3-DNA complexes and van der Waals interactions as the predominant intermolecular forces in stabilizing for each complex. In addition, increasing nucleophilicity of the functional groups at 3- and 8- positions exhibited the respectable increment the DNA binding affinities of derivatives. The results of absorption, ionic strength and iodide ion quenching suggested that the interaction mode of E2 and E3 with ct-DNA was intercalative binding. The limit of detection (LOD) of ct-DNA were 7.49 x 10(-8) (n = 4) and 4.18 x 10(-8) mol/l (n = 7) in presence of E2 and E3, respectively.

In the title compound, C(18)H(10)N(4), the pyrazine ring is oriented at dihedral angles of 48.08 (7) and 44.80 (7)° with respect to the phenyl rings, while the dihedral angle between the phenyl rings is 49.47 (7)°. In the crystal structure, weak π-π contacts between pyrazine and phenyl rings [centroid-centroid distance = 3.813 (1) Å] may stabilize the structure.