Thiophene Moieties Research Articles

Synthesis, characterization, and performance of oligothiophene cyanoacrylic acid derivatives for solar cell applications

New dye sensitizers based on an oligothiophene cyanoacrylic acid derivative were synthesized and characterized for solar cell applications. The structures of the new dyes prepared as sensitizers based on oligothiophenes, namely5,5''-di-2-cyanoacrylic acid [2,2':5',2''-terthiophene] (dye1), [2,2':5',2''-terthiophene]-5-cyanoacrylic acid(dye2), and [2,2':5',2'':5'',2'''-quaterthiophene]-5-cyanoacrylic acid(dye3) were confirmed by elemental analysis, mass spectrometry, and 1H-NMR spectral data. The P3HT/dye2/nc-TiO2 solar cell produced the highest efficiency of 0.05% with an open circuit voltage of 0.65V compared to dyes 1 and 3 solar cells. That may have been attributed to the dyes’ molecular structure, which had different chain lengths and numbers of groups of cyanoacrylic connected to the dyes’ thiophene moiety The dark current suppressed in the P3HT/dye2/nc-TiO2 solar cells indicated the formation of the charge blocking layer, which produced an enhanced open-circuit voltage accompanied by a high onset voltage.

RGB-to-black multicolor electrochromic devices enabled with viologen functionalized polyhedral oligomeric silsesquioxanes

Here we demonstrate multicolor electrochromic transitions of viologen functionalized polyhedral oligomeric silsesquioxanes (POSS-viologens). Highly efficient RGB coverage, including black, was successfully achieved with POSS-viologen employed multi-stacked electrochromic devices (ECDs). We prepared octa-viologen functionalized POSS (OHV-POSS) with the insertion of thiophene (OTxHV-POSS) and phenyl (OPhHV-POSS) moiety. The single-layer ion gel ECDs exhibited outstanding electrochromic performances. OTxHV-POSS and OHV-POSS showed red (R) and blue (B) transitions, respectively, with high transmittance changes and superb coloration efficiency. Saturated green (G) was also obtained from the mixture of OPhHV-POSS and OHV-POSS. Furthermore, multi-stacked ECDs were implemented by combining the RGB coloration layers with multiple electrodes. The two-layer ECDs generated intermediate colors, which was fully translated into the color mixing theory. The three-layer device created real black with blackness L∗ of 6.99, covering 12.9% of the NTSC color gamut. The unprecedented RGB-to-black multicolor coverage, not reported elsewhere, is attributable to the reversible color-switching at a low redox potential for extended cyclic operations. Current findings imply that carefully designed POSS-viologens offer a universal route to high-performance and stable multicolor ECDs, offering compatibility with various pixelized color-changing displays and smart windows.

Multi-sensing response, molecular docking, and anticancer activity of donor–acceptor chalcone containing phenanthrene and thiophene moieties

Donor–Acceptor (D–π–A) chalcone containing phenanthrene and keto-thiophenly moieties, abbreviated as PhTPO, was synthesized and characterized. The solvatochromic effect was investigated in different solvents of various polarities. The absorption and fluorescence spectra have shown bathochromic shifts from non-polar to polar solvents due to intramolecular charge transfer interactions. The fluorescence characteristics (fluorescence intensity, fluorescence maxima, and energy) of PhTPO are highly sensitive to the polarity of the solvents compared to the corresponding absorption spectra. In addition, the inclusion characteristic of PhTPO in different organized assemblies was studied. The spectral changes suggested that PhTPO would be useful to study the microenviromental polarity and evaluation of critical micelle concentrations of the studied surfactants. Reversible acidochromic behavior was observed after addition of H2SO4/NaOH with a significant color change. Further, the optical sensing response towards H+, Co2+, Ni2+, Pb2+ and Cd2+ ions was investigated. Also, it responds well to the tested metal ions as reflected from the changes in both the absorption and emission spectra upon adding different concentrations of the metal salts. The solid complexes of PhTPO with Co2+, Ni2+, Pb2+ and Cd2+ were then synthesized and characterized. Depending on the magnetic moments results, the geometric structures were found to be octahedral and tetrahedral for paramagnetic Co2+, and Ni2+ complexes, respectively, while they are diamagnetic for Pb2+ and Cd2+ complexes. Moreover, the geometry of PhTPO and its complexes were confirmed by the density functional theory (DFT) using DMOL3 program. The binding affinity towards the epidermal growth factor receptor (EGFR) protein was also investigated by the Molecular Operating Environment (MOE) software. The anticancer activity was then evaluated against four different cell lines using MTT assay. The results suggest that the investigated PhTPO would be potential candidate for solvents polarity sensors, as a probe to characterize critical micelle concentrations of surfactants, and sensor for the studied metal ions and H+ proton. In addition, [PhTPONi2+] and [PhTPOCo2+] complexes are good candidate for further antitumor activities studies owing to their potent cytotoxic and anticancer activities compared to the Pb2+ and Cd2+ complexes.

Concise synthesis and biological evaluation of 2-Aryl-3-Anilinobenzo[b]thiophene derivatives as potent apoptosis-inducing agents

Many clinically used agents active in cancer chemotherapy exert their activity through the induction of cell death (apoptosis) by targeting microtubules, altering protein function or inhibiting DNA synthesis. The benzo[b]thiophene scaffold holds a pivotal place as a pharmacophore for the development of anticancer agents, and, in addition, this scaffold has many pharmacological activities. We have developed a flexible method for the construction of a new series of 2-aryl-3-(3,4,5-trimethoxyanilino)-6-methoxybenzo[b]thiophenes as potent antiproliferative agents, giving access to a wide range of substitution patterns at the 2-position of the 6-methoxybenzo[b]thiophene common intermediate. In the present study, all the synthesized compounds retained the 3-(3,4,5-trimethoxyanilino)-6-methoxybenzo[b]thiophene moiety, and the structure–activity relationship was examined by modification of the aryl group at its 2-position with electron-withdrawing (F) or electron-releasing (alkyl and alkoxy) groups. We found that small substituents, such as fluorine or methyl, could be placed in the para-position of the 2-phenyl ring, and these modifications only slightly reduced antiproliferative activity relative to the unsubstituted 2-phenyl analogue. Compounds 3a and 3b, bearing the phenyl and para-fluorophenyl at the 2-position of the 6-methoxybenzo[b]thiophene nucleus, respectively, exhibited the greatest antiproliferative activity among the tested compounds. The treatment of both Caco2 (not metastatic) and HCT-116 (metastatic) colon carcinoma cells with 3a or 3b triggered a significant induction of apoptosis as demonstrated by the increased expression of cleaved-poly(ADP-ribose) polymerase (PARP), receptor-interacting protein (RIP) and caspase-3 proteins. The same effect was not observed with non-transformed colon 841 CoN cells. A potential additional effect during mitosis for 3a in metastatic cells and for 3b in non-metastatic cells was also observed.

Synthesis, crystal structure, density functional theory, Hirshfeld surface analysis and molecular docking studies of 2-(2-phenylanthracen-9-yl)thiophene derivatives

Thiophene containing molecules have been distinguished as potential candidates in the largely emergent chemical world of heterocyclic compounds that show likely pharmacological characteristics. The knowledge of a mixture of synthetic pathways and the different physicochemical parameters of such compounds describe the especial interest of medicinal chemists to produce combinatorial collections and carry out in-depth efforts in the search of lead molecules. Among the various group of compounds studied, thiophene moieties stand out as unique in features due to their biological, pharmacological and medicinal properties. Synthesis, crystal structure, conformation and density functional theory of 2-(2-phenylanthracen-9-yl)thiophene derivative have been investigated in detail. Thiophene moiety are in planar conformation and having C-H…O type of hydrogen bonds and Van der Waals forces. Density functional theory has been applied to the thiophene derivative. Thiophene compounds score highly against the targeted protein and can be compared to the co-crystal ligand. Hirshfeld surface studies have been used to confirm and quantify the supramolecular features.

Assessing the Potency of β-Lactamase Inhibitors with Diverse Inactivation Mechanisms against the PenA1 Carbapenemase from Burkholderia multivorans.

Burkholderia cepacia complex (Bcc) poses a serious health threat to people with cystic fibrosis or compromised immune systems. Infections often arise from Bcc strains, which are highly resistant to many classes of antibiotics, including β-lactams. β-Lactam resistance in Bcc is conferred largely via PenA-like β-lactamases. Avibactam was previously shown to be a potent inactivator of PenA1. Here, we examined the inactivation mechanism of PenA1, a class A serine carbapenemase from Burkholderia multivorans using β-lactamase inhibitors (β-lactam-, diazabicyclooctane-, and boronate-based) with diverse mechanisms of action. In whole cell based assays, avibactam, relebactam, enmetazobactam, and vaborbactam restored susceptibility to piperacillin against PenA1 expressed in Escherichia coli. The rank order of potency of inactivation in vitro based on kinact/KI or k2/K values (range: 3.4 × 102 to 2 × 106 M-1 s-1) against PenA1 was avibactam > enmetazobactam > tazobactam > relebactam > clavulanic acid > vaborbactam. The contribution of selected amino acids (S70, K73, S130, E166, N170, R220, K234, T237, and D276) in PenA1 toward inactivation was evaluated using site-directed mutagenesis. The S130A, R220A, and K234A variants of PenA1 were less susceptible to inactivation by avibactam. The R220A variant was purified and assessed via steady-state inhibition kinetics and found to possess increased Ki-app values and decreased kinact/KI or k2/K values against all tested inhibitors compared to PenA1. Avibactam was the most affected by the alanine replacement at 220 with a nearly 400-fold decreased acylation rate. The X-ray crystal structure of the R220A variant was solved and revealed loss of the hydrogen bonding network between residues 237 and 276 leaving a void in the active site that was occupied instead by water molecules. Michaelis-Menten complexes were generated to elucidate the molecular contributions of the poorer in vitro inhibition profile of vaborbactam against PenA1 (k2/K, 3.4 × 102 M-1 s-1) and was compared to KPC-2, a class A carbapenemase that is robustly inhibited by vaborbactam. The active site of PenA1 is larger than that of KPC-2, which impacted the ability of vaborbactam to form favorable interactions, and as a result the carboxylate of vaborbactam was drawn toward K234/T235 in PenA1 displacing the boronic acid from approaching the nucleophilic S70. Moreover, in PenA1, the tyrosine at position 105 compared to tryptophan in KPC-2, was more flexible rotating more than 90°, and as a result PenA1's Y105 competed for binding with the cyclic boronate vs the thiophene moiety of vaborbactam, further precluding inhibition of PenA1 by vaborbactam. Given the 400-fold decreased k2/K for the R220A variant compared to PenA1, acyl-enzyme complexes were generated via molecular modeling and compared to the PenA1-avibactam crystal structure. The water molecules occupying the active site of the R220A variant are unable to stabilize the T237 and D276 region of the active site altering the ability of avibactam to form favorable interactions compared to PenA1. The former likely impacts the ability of all inhibitors to effectively acylate this variant enzyme. Based on the summation of all evidence herein, the utility of these newer β-lactamase inhibitors (i.e., relebactam, enmetazobactam, avibactam, and vaborbactam) in combination with a β-lactam against B. multivorans producing PenA1 and the R220A variant is promising.

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities.

A series of fifteen silver (I) quinoline complexes Q1–Q15 have been synthesized and studied for their biological activities. Q1–Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1–L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1–Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3 Q1, [Ag(L1)2]ClO4 Q6, [Ag(L2)2]ClO4 Q7, [Ag(L2)2]CF3SO3 Q12 and [Ag(L4)2]CF3SO3 Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes′ moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4 Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4 Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.

Chimeric Drug Design with a Noncharged Carrier for Mitochondrial Delivery.

Recently, it was proposed that the thiophene ring is capable of promoting mitochondrial accumulation when linked to fluorescent markers. As a noncharged group, thiophene presents several advantages from a synthetic point of view, making it easier to incorporate such a side moiety into different molecules. Herein, we confirm the general applicability of the thiophene group as a mitochondrial carrier for drugs and fluorescent markers based on a new concept of nonprotonable, noncharged transporter. We implemented this concept in a medicinal chemistry application by developing an antitumor, metabolic chimeric drug based on the pyruvate dehydrogenase kinase (PDHK) inhibitor dichloroacetate (DCA). The promising features of the thiophene moiety as a noncharged carrier for targeting mitochondria may represent a starting point for the design of new metabolism-targeting drugs.

Identification of potential descriptors of water-soluble fullerene derivatives responsible for antitumor effects on lung cancer cells via QSAR analysis

Water-soluble fullerene derivatives are actively investigated as potential drugs for cancer treatment due to their favorable membranotropic properties. Herein, cytotoxic effects of twenty fullerene derivatives with different solubilizing addends were evaluated in three different types of non-small-cell lung carcinoma (NSCLC). The potential structural descriptors of the solubilizing addends related to the inhibitory activities on each type of lung cancer cell were investigated by the quantitative structure–activity relationship (QSAR) approach. The determination coefficient r2 for the recommended QSAR model were 0.9325, 0.8404, and 0.9011 for A549, H460, and H1299 cell lines, respectively. The results revealed that the chemical features of the fullerene-based compounds including aromatic bonds, sulfur-containing aromatic rings, and oxygen atoms are favored properties and promote the inhibitory effects on H460 and H1299 cells. Particularly, thiophene moiety is the key functional group, which was positively correlated with strong inhibitory effects on the three types of lung cancer cells. The useful information obtained from our regression models may lead to the design of more efficient inhibitors of the three types of NSCLC.

Phenanthrotriazine Derivatives Containing Arylidine Hydrazone Moieties as Novel Potential c-Met Inhibitors with Anticancer Effect.

Cancer is the second cause of death in the world and the discovery of novel anticancer agents is of vital importance to provide better therapeutic options for cancer patients. In this study, a new series of 12 arylidene hydrazone phenanthrotriazine derivatives were designed, synthesized, and tested in-vitro for antiproliferative activity against three cancer cell lines including colorectal cancer (HT-29), breast cancer (MCF-7) and leukemia (MOLT-4) cells and also against Vero normal cells. The effect of derivatives on cell cycle and apoptosis induction were studied by flow cytometric propidium iodide/RNase assay and Hoechst 33258 staining, respectively, while docking analysis was used to investigate the interactions of synthesized derivatives with the c-Met receptor kinase domain. Some compounds showed considerable antiproliferative activity against tested cancer cells. The most potent derivative was 9k bearing pyrrole moiety with IC50 values of 14.3, 4.7 and 1.7 µM against HT-29, MCF-7 and MOLT-4 cells, respectively, while it showed negligible activity against Vero normal cells (IC50: 95.4 µM). Derivatives bearing 2-nitrophenyl (9g), 4-cyanophenyl (9j), pyrrole (9k), and thiophene (9l) moieties induced G0/G1 cell cycle arrest and also apoptosis at higher doses in MCF-7 cells. Docking study showed that the phenanthrotriazine backbone form H-bond interactions with Asn1209, while phenyl moieties of the pendants generate different hydrophobic interactions with the Asp1164 and Asp1231 residues of c-Met. In conclusion, phenanthrene 1,2,4-triazines, especially the ones with less influence on normal cells, may constitute promising compounds for the discovery of antiproliferative agents with potential c-Met inhibitory capacity.

СИНТЕЗ И ОПТИЧЕСКИЕ СВОЙСТВА НОВЫХ 4-ЗАМЕЩЕННЫХ ПИРИМИДИНОВ- ХРОМОФОРОВ D-A ТИПА

The set of 4-aryl(hetaryl)pyrimidines, where aryl/hetaryl is a highly electron donating substituent was synthesized. Optical and electrochemical properties of the synthesized compounds were studied and the values of a forbidden band gap energy ( ) were determined. The narrowest bandgap was found to be inherent to 4-ferrocenylpyrimidine (1.8 eV) and the most long-wavelength emission maximum ‑ to para-substituted pyrimidine which structure embeds a thiophene moiety between N-hexylcarbazolyl fragment and the pyrimidine core (577 нм).

Antimicrobial Furancarboxylic Acids from a Penicillium sp.

Ten novel (1, 2, 3a, 3b, 4a, 4b, 5a, 5b, 6a, and 6b) furancarboxylic acids including four pairs of epimers (3a, 3b; 4a, 4b; 5a, 5b; 6a, 6b), together with seven known analogues (7a, 7b, 8a, 8b, 9a, 9b, and 10), were isolated from the fermentation of the soil-derived fungus Penicillium sp. sb62. Their structures were established on the basis of spectroscopic data analysis, and the absolute configurations were determined by time-dependent density functional theory electronic circular dichroism calculations, comparison of the specific optical rotation values, and modified Mosher's method. Compounds 1-4 represent the first class of natural furancarboxylic acids featuring a thiophene moiety. Compounds 1-7 showed antimicrobial inhibitory activities against Escherichia coli, Staphylococcus aureus, and Candida albicans with MIC values ranging from 0.9 to 7.0 μg/mL, from 1.7 to 3.5 μg/mL, and from 3.3 to 7.0 μg/mL, respectively.

Design of Thienothiophene-Based Copolymers with Various Side Chain-End Groups for Efficient Polymer Solar Cells.

Three two-dimensional donor–acceptor conjugated copolymers consisting of a benzo[1,2-b:4,5-b′]dithiophene derivative and thieno[3,2-b]thiophene with a conjugated side chain were designed and synthesized for use in bulk heterojunction (BHJ) or nonfullerene polymer solar cells (PSCs). Through attaching various acceptor end groups to the conjugated side chain on the thieno[3,2-b]thiophene moiety, the electronic, photophysical, and morphological properties of these copolymers were significantly affected. It was found that the intermolecular charge transfer interactions were enhanced with the increase in the acceptor strength on the thieno[3,2-b]thiophene moiety. Moreover, a better microphase separation was obtained in the copolymer: PC71BM or ITIC blend films when a strong acceptor end group on the thieno[3,2-b]thiophene moiety was used. As a result, BHJ PSCs based on copolymer:PC71BM blend films as active layers exhibited power conversion efficiencies from 2.82% to 4.41%, while those of nonfullerene copolymer:ITIC-based inverted PSCs ranged from 6.09% to 7.25%. These results indicate the side-chain engineering on the end groups of thieno[3,2-b]thiophene unit through a vinyl bridge linkage is an effective way to adjust the photophysical properties of polymers and morphology of blend films, and also have a significant influence on devices performance.

Structural origins of carbon quantum dot luminescence by synchrotron x-ray spectroscopy

A carbon quantum dot (CQD) sample series was synthesized from citric acid and varying concentrations of thiourea. The highest (sample 1) and lowest (sample 2) concentrations of thiourea exhibited unique visual effects and electronic structures. X-ray excited optical luminescence (XEOL) along with UV-visible spectroscopy provided unique insight into the absorption and emission mechanisms of samples 1 and 2, where only sample 2 emitted XEOL. Sample 1 exhibited the commonly observed aggregation caused quenching (ACQ) effects in the solid state. While sample 2 displayed unique aggregation induced emissions (AIE) effects upon exciting the sample above the C K edge. The AIE and ACQ sample differences were suspected to be from S moiety differences arising from the varying thiourea concentrations during synthesis. Furthermore, x-ray absorption spectroscopy (XAS) in modes of total electron yields (TEY) and partial fluorescence yields (PFY) allowed the identification of specific core and surface states of the CQDs. It was discovered that thiophene moieties were uniquely formed in the AIE sample’s surface and not anywhere in the ACQ CQD sample. The thiophene surface functionality is believed to be a significant contributor to the AIE effects seen in the XEOL studies. Understanding and preventing the common CQD ACQ mechanism allows the application of CQDs in solid lighting applications.

New Zileuton-Hydroxycinnamic Acid Hybrids: Synthesis and Structure-Activity Relationship towards 5-Lipoxygenase Inhibition.

A novel series of zileuton-hydroxycinnamic acid hybrids were synthesized and screened as 5-lipoxygenase (5-LO) inhibitors in stimulated HEK293 cells and polymorphonuclear leukocytes (PMNL). Zileuton’s (1) benzo[b]thiophene and hydroxyurea subunits combined with hydroxycinnamic acid esters’ ester linkage and phenolic acid moieties were investigated. Compound 28, bearing zileuton’s (1) benzo[b]thiophene and sinapic acid phenethyl ester’s (2) α,β-unsaturated phenolic acid moiety 28, was shown to be equipotent to zileuton (1), the only clinically approved 5-LO inhibitor, in stimulated HEK293 cells. Compound 28 was three times as active as zileuton (1) for the inhibition of 5-LO in PMNL. Compound 37, bearing the same sinapic acid (3,5-dimethoxy-4-hydroxy substitution) moiety as 28, combined with zileuton’s (1) hydroxyurea subunit was inactive. This result shows that the zileuton’s (1) benzo[b]thiophene moiety is essential for the inhibition of 5-LO product biosynthesis with our hydrids. Unlike zileuton (1), Compound 28 formed two π–π interactions with Phe177 and Phe421 as predicted when docked into 5-LO. Compound 28 was the only docked ligand that showed a π–π interaction with Phe177 which may play a part in product specificity as reported.

Synthesis of a New Class of Spirooxindole-Benzo[b]Thiophene-Based Molecules as Acetylcholinesterase Inhibitors.

A series of new oxindole-based spiro-heterocycles bearing the benzo[b]thiophene motif were synthesized via a 1,3-dipolar cycloaddition reaction and their acetylcholinesterase (AChE) inhibitory activity was evaluated. All the synthesized compounds exhibited moderate inhibitory activities against AChE, while IIc was found to be the most active analog with an IC50 value of 20,840 µM·L−1. Its molecular structure was a 5-chloro-substituted oxindole bearing benzo[b]thiophene and octahydroindole moieties. Based on molecular docking studies, IIc was strongly bound to the catalytic and peripheral anionic sites of the protein through hydrophilic, hydrophobic, and π-stacking interactions with Asp74, Trp86, Tyr124, Ser125, Glu202, Ser203, Trp236, Trp286, Phe297, Tyr337, and Tyr341. These interactions also indicated that the multiplicity of the IIc aromatic core significantly favored its activity.

Crystal structure, linear and nonlinear optical properties of three thiophenyl chalcone derivatives: A combined experimental and computational study

Abstract Three thiophenyl chalcone derivatives, (E)-1-(5-bromo-2-thienyl)-3-(4-bromophenyl)prop-2-en-1-one (B5B2SC), (E)-1-(5-bromo-2-thienyl)-3-(3-chlorophenyl)prop-2-en-1-one (3C5B2SC), and (E)-1-(5-bromo-2-thienyl)-3-(2-methoxyphenyl)prop-2-en-1-one (2M5B2SC), were successfully synthesized and crystallized. The structures were confirmed by experimental and theoretical FTIR and 1H NMR spectra. The crystal structures were determined by single-crystal XRD method. The B5B2SC, 3C5B2SC and 2M5B2SC crystallize in the monoclinic space groups P 21/c (centrosymmetric), P 2 (non-centrosymmetric) and triclinic space group P 1 ‾ (centrosymmetric), respectively. All these structures adopt trans configuration with respect to C6═C7 double bond. The chalcones have high thermal stability, a wide transparency in the visible region and small optical band gaps. The 3C5B2SC exhibits powder second-harmonic generation (SHG) intensity of about 1.7 times higher than Urea. From continuous wave (CW) laser (532 nm) Z-scan experimental data analyses, the third-order NLO parameters such as nonlinear absorption coefficient (β = ~10−4 cm/W), nonlinear refractive index (n2= ~10−9 cm2/W), third-order NLO susceptibility (χ(3) = ~10−7 esu), molecular hyperpolarizability (γh = ~10−27 esu), ground state absorption cross section (σg = ~10−22 cm2) and excited state cross sections (σex= ~10−20 cm2) were determined. The chalcones also exhibited optical limiting and all optical switching behaviour for CW laser operating at 532 nm wavelengths. The electric dipole moment, polarizability, hyperpolarizabilty, HOMO-LUMO energy gap, global chemical reactivity descriptors (GCRD), molecular electrostatic potentials (MEP) and natural bond orbital (NBO) analysis were computed theoretically (DFT). The results indicate that these three chalcones with thiophene moiety are potential materials for optical device applications.

Aryl variation and anion effect on CT-DNA binding and in vitro biological studies of pyridinyl Ag(I) complexes

Synthesis and spectroscopic characterization of five ligands ((E)-2-((pyridin-2-ylmethylene)amino)phenol L1, 2-(pyridin-2-yl)benzo[d]thiazole L2, (E)-N-(2-fluorophenyl)-1-(pyridin-2-yl)methanimine L3, (E)-1-(pyridin-2-yl)-N-(p-tolyl)methanimine L4 and (E)-1-(pyridin-2-yl)-N-(thiophen-2-ylmethyl)methanimine L5 along with fifteen silver(I) complexes of L1 – L5, with a general formula [AgL2]+X− (L = Schiff base and X = NO3−, ClO4− or CF3SO3−) is reported. The structures of complexes [Ag(L4)2]NO3, [Ag(L5)2]NO3, [Ag(L3)2]ClO4, [Ag(L4)2]ClO4 and [Ag(L5)2]CF3SO3 were determined unequivocally by single crystal X-ray diffraction analysis. Calf-thymus deoxyribonucleic acid (CT-DNA), bovine serum albumin (BSA) binding studies, antioxidant, and antibacterial studies were performed for all complexes. Complexes [Ag(L2)2]NO3, [Ag(L5)2]NO3, [Ag(L1)2]ClO4 and [Ag(L3)2]ClO4 whose ligands have an OH− and F− as substituents or with a thiophene or thiazole moiety showed better antibacterial activities with lower minimum inhibitory concentration (MIC) values compared to the standard ciprofloxacin, against most of the bacterial strains tested. Similarly, complexes [Ag(L1)2]NO3,[Ag(L2)2]NO3,[Ag(L3)2]NO3 and [Ag(L5)2]NO3 with the NO3− anion, [Ag(L1)2]ClO4 and [Ag(L2)2]ClO4 with ClO4− anion, and [Ag(L5)2]CF3SO3 with CF3SO3− anion showed higher activities for antioxidant studies. Complexes [Ag(L4)2]ClO4 and [Ag(L4)2]CF3SO3 with the Methyl substituent and CF3SO3− as the anion, displayed high antioxidant activities in FRAP (ferric reducing antioxidant power) than the standard ascorbic acid. Spectroscopic studies of all the complexes revealed their moderate to high interaction with calf thymus DNA via an intercalation mode. In addition, the relatively moderate interaction of most of the complexes with BSA was through a static quenching mechanism.

Structural, linear optical, second and third-order nonlinear optical properties of two halogenated chalcone derivatives containing thiophene moiety

Two halogenated chalcones B3B2SC and C3B2SC were synthesized for NLO applications. Single-crystal X-ray diffraction, spectroscopic (NMR and FT-IR), thermal and DFT studies were performed. Both the crystals are crystallized in the monoclinic non-centrosymmetric Pn space group. The SHG efficiency of both the chalcones is higher than urea. The third-order NLO parameters, optical limiting and optical switching properties of the chalcones were investigated by Z-scan method using a CW laser at 532 nm. The experimental and computational linear and nonlinear optical studies revealed that both the chalcone are promising materials for NLO applications.

Synthesis of new heterocycles festooned with thiophene and evaluating their antioxidant activity

AbstractThe chemical performance of 5‐bromo‐2‐(bromoacetyl)‐thiophene (1) was tested toward the reaction with numerous bi‐nucleophilic reagents (namely; 2‐aminobenzothiazoles, 2‐aminothiazole, 2‐aminotetrazole, 2‐aminotriazole, 2‐aminopyridines, 2‐aminobenzimidazole and o‐phenylenediamine). Therefore, a series of bridged nitrogen heterocycles bearing thiophene moiety 3, 5, 7, 9, 11, 13 and 15, respectively was synthesized. In addition, the reaction of 5‐bromo‐2‐(bromoacetyl)‐thiophene with the thiocarbamoyl compounds 17, 19 and/or 24 afforded the corresponding thienyl‐thiazoles 18 or dithien‐2‐yl ketones 20 and 25, based on the reaction conditions. Treatment of 1 with 2‐mercapto‐4,6‐dimethylnicotinonitrile was achieved to obtain the target dithien‐2‐yl ketone 28. The new synthesized scaffolds were examined for their antioxidant activity by means of ABTS antioxidant assay. The thienyl‐thiazole scaffold 18c and 2‐((2‐[thiophen‐2‐yl]‐2‐oxoethyl)thio)nicotinonitrile derivative 27 displayed a reasonable radical scavenging activity.