Nickel(II) and copper(II) complexes constructed with N2S2 hybrid benzamidine–thiosemicarbazone ligand: synthesis, X-ray crystal structure, DFT, kinetico-catalytic and in vitro biological applications

With the aim of assessing whether transition metal complexes might be utilized as efficient biocatalysts and biological drugs, new monofunctional nickel(II) and copper(II) complexes of types NiL (1) and CuL (2) [H2L ¼ N-(N0 ,N0-diethylaminothiocarbonyl)benzimidoyl chloride-2-aminoacetophenone-N-methylthiosemicarbazone] were synthesized. The compounds are remarkably stable and were obtained in good yields. Structural elucidation was carried out thoroughly in solid and solution-states by elemental analysis and various spectroscopy techniques (IR, UV-vis, 1H NMR, and EPR) as well as ESI mass spectrometry. The molecular structure of the compounds was investigated by single-crystal X-ray diffraction. The analyses showed tetradentate coordination of the ligand in nickel(II) and copper(II) complexes, in which the metal atom exhibits a square planar geometry with N2S2 in a donor fashion. Structural optimization, HOMO–LUMO energy calculations and Natural Bond Orbital (NBO) analysis of H2L and its complexes (1 and 2) were investigated by Density Functional Theory (DFT). The trend in binding affinities of the compounds with biomolecules, such as calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) protein, were investigated by different spectrophotometric methods, which revealed an intercalative mode of interaction. Furthermore, enzyme kinetic studies reflected that the square planar complexes (1 and 2) are also effective in mimicking catecholase (3,5-DTBC) and phosphatase (4-NPP) activities over the parent H2L. The high kcat values suggested that the selected compounds displayed a high rate of catalytic efficiency. In vitro cytotoxicity of the complexes on human skin cancer melanoma (A375), human cervical cancer (HeLa) and human hepatocellular carcinoma (Hep3B) cancer cell lines demonstrated that the complexes had a broad-spectrum of anti-cancer activity with low IC50 values. The morphological assessment data obtained by acridine orange/ethidium bromide (AO/EB) and diamidino-2-phenylindole (DAPI) staining revealed that complex 2 induces apoptosis much more effectively than 1

Reduced graphene oxide-resorcinol nanocomposite: A chemosensor for the detection of cerium ions

A hybrid material reduced graphene oxide based organic nanocomposite was synthesized from graphite by modified Hummers method, which is further chemically reduced to form reduced graphene oxide (rGO) and with resorcinol through a solvothermal process a reduced graphene oxide-resorcinol (rGO-R) nanocomposite was obtained. The synthesized materials surface morphology and structural compositions were studied through X-ray diffraction (XRD) and scanning electron microscope (SEM) and their optical properties were studied through UV-visible spectroscopy and photoluminescence. The material was further used as a fluorescent chemosensor to detect cerium ion under aqueous conditions. The rGO-R composite's sensing abilities were studied by following parameters viz. pH, reversibility, time and the interference of other probable competing ions. The sensing follows both the photo-induced electron transfer and intramolecular charge transfer processes. © 2021 Chemical Publishing Co.. All rights reserved.Department of Science and Technology, Ministry of Science and Technology, India, डीएसटी: SERB-EMR/2016/00569

Low-dose ketamine infusion for labor analgesia: A double-blind, randomized, placebo controlled clinical trial

Background: Most primary and secondary level hospitals in developing countries provide inadequate labor analgesia due to various medical, technical and economic reasons. This clinical trial was an effort to study the efficacy, safety and feasibility of intravenous (IV) ketamine to provide labor analgesia. Materials and Methods: A total of 70 parturients were consented and randomly assigned to receive either IV ketamine or 0.9% saline. A loading dose of ketamine (0.2 mg/kg) was followed-by an infusion (0.2 mg/kg/h) until the delivery of the neonate. Similar volume of saline was infused in the placebo-group. Intramuscular meperidine was the rescue analgesic in both groups. The pain score, hemodynamic parameters of mother and fetus and the anticipated side-effects of ketamine were observed for. The newborn was assessed by the Neonatologist. Results: The pain score showed a decreasing trend in the ketamine group and after the 1 st h more than 60% of women in the ketamine group had pain relief, which was statistically significant. There was no significant clinical change in the maternal hemodynamics and fetal heart rate. However, 17 (48.5%) of them had transient light headedness in the ketamine group. All the neonates were breast fed and the umbilical cord blood pH was between 7.1 and 7.2. The overall satisfaction was significantly high in the intervention group (P = 0.028). Conclusion: A low-dose ketamine infusion (loading dose of 0.2 mg/kg delivered over 30 min, followed-by an infusion at 0.2 mg/kg/h) could provide acceptable analgesia during labor and delivery

Organoruthenium(II) compounds with pyridyl benzoxazole/benzthiazole moiety: studies on DNA/protein binding and enzyme mimetic activities

<p>We report herein synthesis and characterization of four new organoruthenium(II) complexes of the type [RuH(CO)(PPh₃)₂(<b>L</b>_<b>1,2</b>)]Cl (<b>1</b>, <b>3</b>) and [Ru(CO)(Cl)₂(AsPh₃)(<b>L</b>_<b>1,2</b>)] (<b>2</b>, <b>4</b>) derived from the reaction of [RuHCl(CO)(EPh₃)₃] (E = P or As) with 2-(pyridine-2yl)benzoxazole (<b>L</b>_<b>1</b>) and 2-(pyridine-2yl)benzthiazole (<b>L</b>_<b>2</b>). Single-crystal X-ray diffraction data of <b>2</b> proved octahedral geometry of the complexes with a 1 : 1 ratio between the metal and the coordinated ligands. The binding affinities of <b>1</b>–<b>4</b> toward calf-thymus DNA (CT-DNA) and BSA were thoroughly studied by various spectroscopic techniques. Furthermore, the coordination compounds exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding <i>o</i>-quinone and phosphatase-like activities in the hydrolysis of 4-nitrophenyl phosphate to 4-nitrophenolate ion. The kinetic parameters have been determined using Michaelis–Menten approach. The highest <i>k</i>_cat values suggested that coordination compounds exhibit higher rates of catalytic efficacy.</p

BINOl‑Based Chiral Receptors as Fluorescent and Colorimetric Chemosensors for Amino Acids

Three representative BINOL derivatives were examined for their chiral recognitions with d- and l-<i>t</i>-Boc-amino acid anions: an open system 1, which bears two urea groups and two pyrene groups; a closed ring system 2, which bears two urea groups with a closed ring system; and a dimeric system 3, which bears two benzylic amine groups and two pyrene groups. Dimeric system 3 displayed a Δ<i>I</i>_D/Δ<i>I</i>_L of 12.95 for <i>t</i>-Boc-alanine

Graphdiyne–ZnO Nanohybrids as an Advanced Photocatalytic Material

The utility of carbonaceous materials for hybrid semiconductor photocatalysts has been rapidly increasing in recent years due to the synergetic effect via interfacial charge transfer reactions. In this study, we prepared a novel graphdiyne–ZnO nanohybrid by the hydrothermal method and examined its photocatalytic properties on the degradation of two azo dyes (methylene blue and rhodamine B). Interestingly, the graphdiyne–ZnO nanohybrids showed superior photocatalytic properties than that of the bare ZnO nanoparticles as evidenced by the absorption spectra and total organic carbon analyses. Moreover, the rate constant of graphdiyne–ZnO nanohybrids is nearly 2-fold higher compared to that of the bare ZnO nanoparticles on the photodegradation of both azo dyes. Further, a plausible mechanism for the enhanced photocatalytic properties of the graphdiyne–ZnO nanohybrids has been discussed. This work on the development of graphdiyne-based semiconductor photocatalysis can provide new insights into the design of novel hybrid photocatalysts for potential applications in the environmental remediation sectors