A series of 22 different 3,5-diarylidenetetrahydro-2H-pyran-4(3H)-ones (DATPs) were synthesized, characterized, and screened for their in vitro antiplasmodial activities against chloroquine (CQ)-sensitive Pf3D7, CQ-resistant PfINDO, and artemisinin-resistant PfMRA-1240 strains of Plasmodium falciparum. DATP 19 (3,5-bis(4-hydroxy-3,5-dimethoxybenzylidene)tetrahydro-2H-pyran-4(3H)-one) was found to be the most potent (IC50 1.07 mu M) against PfMRA-1240, whereas 21 (3,5-bis(3,4,5-trimethoxybenzylidene)tetrahydro-2H-pyran-4(3H)-one) showed IC50 values of 1.72 and 1.44 mu M against Pf3D7 and PfINDO, respectively. Resistance indices (RI) as low as 0.2 to 0.5 for 10 (3,5-bis(4-nitrobenzylidene)tetrahydro-2H-pyran-4(3H)-one) and 20 (3,5-bis(3-nitrobenzylidene)tetrahydro-2H-pyran-4(3H)-one), and 21 are reported. In silico support was obtained through docking studies. Killing all three strains within 4-8 h, these DATPs showed rapid kill kinetics toward the trophozoite stage. Furthermore, DATP 18 (3,5-bis(quinolin-4-ylmethylene)tetrahydro-2H-pyran-4(3H)-one) inhibited PfPdx1 enzyme activity with IC50 20.34 mu M, which is about twofold lower than that (IC50 43 mu M) for an already known inhibitor 4PEHz. At an oral dose of 300 mg/kg body weight, DATPs 19 and 21 were found to be nontoxic to mice, and at 100 mg/kg body weight, DATP 19 was found to suppress parasitaemia, which led to an increase in median survival time by three days relative to untreated control mice in a malaria curative study.

Misfolding and protein aggregation have been linked to numerous human neurodegenerative disorders such as Alzheimer's, prion, and Parkinson's diseases. Ruthenium (Ru) complexes have received considerable attention in studying protein aggregation due to their interesting photophysical and photo properties. In this study, we have synthesized the novel Ru complexes ([Ru(p-cymene)Cl(L-1)][PF6](Ru-1), and [Ru(p-cymene)Cl(L-2)][PF6](Ru-2)) and investigated their inhibitory activity against the bovine serum albumin (BSA) aggregation and the Aβ1-42 peptides amyloid formation. Several spectroscopic methods were used to characterize these complexes, and the molecular structure of the complex was determined by X-ray crystallography. Amyloid aggregation and inhibition activities were examined using the Thioflavin-T (ThT) assay, and the secondary structures of the protein were analyzed by circular dichroism (CD) spectroscopy and transmission electron microscopy (TEM). The cell viability assay was carried out on the neuroblastoma cell line, revealing that the complex Ru-2 showed better protective effects against Aβ1-42 peptide toxicity on neuro-2a cells than the complex Ru-1. Molecular docking studies elucidate the binding sites and interactions between the Ru-complexes and Aβ1-42 peptides. The experimental studies revealed that these complexes significantly inhibited the BSA aggregation and Aβ1-42 amyloid fibril formation at 1:3 and 1:1 molar concentrations, respectively. Antioxidant assays demonstrated that these complexes act as antioxidants, protecting from amyloid-induced oxidative stress. Molecular docking studies with the monomeric Aβ1-42 (PDB: 1IYT) show hydrophobic interaction, and both complexes bind preferably in the central region of the peptide and coordinate with two binding sites of the peptide. Hence, we suggest that the Ru-based complexes could be applied as a potential agent in metallopharmaceutical research against Alzheimer's disease.

The structural and computational analysis of small organic compounds containing four fluorine atoms is the theme of this manuscript. A library of fluorinated compounds containing a secondary amide (-CONAr2) group has been synthesized and structurally characterized to understand the influence of multiple C-F bonds in building various supramolecular synthons. The introduction of four C-F bonds in each molecule has resulted into a variety of fluorine-mediated weak hydrogen-bonded synthons and a few C-F & BULL;& BULL;& BULL;F-C contact-mediated molecular dimers. These molecules offer the possibility of exploring the wide variation in crystal structures resulting from different types of weak interactions offered by organic fluorine (C-F group) connected to an aromatic ring. Herein, we intend to demonstrate the significance of those interactions using structural and computational methods.

Among the halogens, fluorine plays a crucial role in governing the potency of drugs and pharmaceuticals. In this study, experimental and theoretical charge density analyses have been performed on N-(2,5-difluorophenyl)-3,5-difluoro-N-(3-methoxyphenethyl)benzamide to study the nature of weak intermolecular interactions, especially the F center dot center dot center dot F interactions, mediated by organic fluorine. The kind of C-F center dot center dot center dot F-C interactions analyzed in this study are Type I and quasi Type I/Type II. For this, the quantitative and qualitative analyses of electron densities have been performed based on the multipole modeling of high-resolution experimental X-ray diffraction data and theoretical structure factors generated from periodic calculations. The interactions have been analyzed based on the topological properties of electron densities using quantum theory of atoms in molecules (QTAIM). Thus, the nature of organic fluorine has been investigated by studying deformation of electron densities, Laplacian, and topological parameters.

This study aims to explore the coordination motifs of a Schiff base towards zinc ions in the presence of pseudohalides and study the electrical charge transport properties of the zinc complexes under dark and light conditions.

Biologically active benzimidazoles are well-known for their therapeutic applications; however, the molecular systems enable their impact in various optical applications. We report a catalyst-free synthesis of methyl-substituted benzimidazole compounds. The benzimidazole derivatives, 2-(p-tolyl)-1H-benzo [d]imidazole (4-Me) and 2-mesityl-1H-benzo[d]imidazole (246-Trime) were synthesized in an oxygenated-aqueous medium through the reaction of ortho-phenylenediamine and methyl-substituted benzaldehydes at 75 degrees degrees C. The photophysical properties of the benzimidazole scaffolds were investigated in the aqueous medium. 4-Me and 246-Trime derivatives in their aggregated form in solid state displayed a red shift of absorbance and fluorescence intensity relative to their molecular form in the aqueous medium. Spectroscopic, structural and morphological characteristics of the benzimidazole compounds reveal that effective supramolecular interactions are operative to decelerate the intramolecular movements of 4-Me and 246-Trime leading to J-type molecular aggregates. The supramolecular interactions and energy framework analysis of the compounds suggest that strong and short C-H center dot center dot center dot pi interactions with very strong and short intermolecular N center dot center dot center dot H hydrogen bonding play important role for the development of molecular aggregates and attribute the contribution of dispersive energy to a large extent for the stabilization of 4-Me and 246-Trime molecular aggregates. The para positional effect of the methyl group in the benzimidazole derivatives marks a notable impact on the additional stability of the blue light-emitting molecular aggregates of nano-dimension. (C) 2021 Elsevier B.V. All rights reserved.

The structural features of metal-organic frameworks (MOFs) are very tempting and have proven themselves to be promising candidates for different applications such as gas storage and separation, catalysis, sensing, magnetism, drug delivery, and so forth. The nanotubular structure of MOFs leads to a new class called metal-organic nanotubes (MONTs), which are structurally analogous to carbon nanotubes. Herein, we explored the electrical conductivity and photoconductivity of two isostructural MONTs, [Zn-3(btc)(2)(mu 3-OH) (DMF)]center dot H2O (Zn-Zn-btc) and (ZnNi2(btc)(2)(mu 3-OH)DMF)center dot H2O (Zn-Ni-btc). Solvent activation, followed by thermal activation of Zn-Zn-btc and Zn-Ni-btc MOFs result in an increase of electrical conductivity by 3 and 2 orders, respectively. The remarkable increment in conductivity after evacuating the porous channels marks the significance of MONTs. The electrical conductivity of Zn-Zn-btc is 100 times higher than that of Zn-Ni-btc despite the fact that both are isostructural. The lower conductivity of Zn-Ni-btc is attributed to the low charge carrier density and mobility due to atomic mismatch. Zn-Ni-btc displays a decrease in conductivity with increasing temperature (above room temperature), which then starts to increase after 373 K, showing lattice vibration-mediated transport below 373 K and hopping-mediated electrical transport above 373 K. Whereas Zn-Zn-btc shows a continuous decrease in conductivity with temperature mainly due to the phonon-mediated transport mechanism. Both the compounds show a photoconductivity effect at room temperature. The blue light-induced photoconductivity of Zn-Ni-btc is almost 14% higher than that of Zn-Zn-btc. The photoswitching effect is shown by both the MONTs.

Since Ni and Cd belong to the 3d and 4d series of transition elements respectively, common perception insists that Ni-Se and Cd-Se bond distances in molecular complexes will be quite different. Present work reports the successful synthesis and detailed characterization of cis-configured mononuclear complex [Ni(SeC5H4N)(2)(dppe)] (1) as well as novel tetranuclear heterometallic Ni-Cd complex [(Ni-2(kappa(2)-SeC5H4N)(2)(mu-OCH3)CdCl}(2)] (2 ). Here, the complex [Ni(SeC5H4N)(2)(dppe)] act as building block for the preparation of complex 2 which has similar Ni-Se and Cd-Se bond distances (within 0.1 angstrom). The closeness of these bond lengths has facilitated the preparation of NiSe/CdSe heterostructure. The prepared NiSe/CdSe heterostructure has been thoroughly characterized by pXRD, SEM, TEM and EDS, while diffuse reflectance spectroscopy (DRS) was used to evaluate the bandgap of the heterostructure. Detailed struc-tural analysis of molecular assembly further endorses that bond length similarity of Ni-Se and Cd-Se in complex appears as the key factor in getting the heterostructure upon thermolysis of complex. DFT calculations revealed that underlying spin moments of heterometallic system commands the complex to have Ni-Se and Cd-Se bond distances within 0.1 A range. The magnetic interactions in complex were reaffirmed by weak ferromagnetic ordering observed in superconducting quantum interference device (SQUID) analysis of molecular assembly at lower temperature. It is believed that controlled preparation of NiSe/CdSe heterostructure from novel single source heterometallic precursor reported in the present work will assist the synthesis of functional chalcogenide materials with technological importance. (C) 2021 Elsevier B.V. All rights reserved.

We have synthesized 3 benzothiazole crystals (1–3) based on existing knowledge of combining flexibility and optical properties towards achieving applications for flexible optoelectronics. However, one crystal was found to be elastically bendable and was found to comply necessary packing features for elasticity. Other two crystals do not obey packing features for elasticity hence they are brittle in nature. Further, Hirshfeld analysis illustrates that elastic crystal 1 possess more number of weak and dispersive interactions compared to other crystals. These interactions were instrumental in invoking elasticity. Moreover, crystals 1–3 were found to be fluorescent as well at specific excitation wavelengths. Therefore, among these crystals, particularly crystal 1 is considered as more promising candidate for flexible optoelectronics.

A library of halogen-substituted azobenzenes (ABs) have been synthesized and structurally characterized by single crystal X-ray diffraction technique. Azobenzenes studied herein display fast photo switching properties. Kinetics of cis- -> trans- isomerization has been studied using UV-VIS spectroscopy and the rate constant for this transformation were determined. Optimization of probable conformers of the cis- isomer and the corresponding transition state (TS) were carried out to determine the energy of activation. The Time-Dependent Density Functional Theory (TD-DFT) calculations were also performed to gain insight into the photo-isomerization. Our results indicate that the fluorinated compounds display better kinetic stability of the cis- isomer compared to the corresponding chloro and bromo analogues.