Reactions of titanium(IV) isopropoxide with aliphatic and aromatic hydroxy esters,part I. 5-, 6-, 7- and 8-coordinate titanium(IV) complexes

Summary Reactions of titanium(IV) isopropoxide with ethyl 1-hydroxycyclohexylacetate, ethyl 2-hydroxy-2-arylpropionate, ethyl 2-hydroxy-2-arylbutyrate and ethyl 2-hydroxy-2-arylhydrocinnamate have been studied in dry benzene in different molar ratios under strictly anhydrous conditions. The Ti(OPr-i)₄-_nL_n type compounds, where L = hydroxy ester and n = 1 to 4, have been isolated and characterised by elemental analysis, molecular weight, i.r. and n.m.r. spectral studies. These products may be distilled unchanged under reduced pressure.Reprints of this are not available.     

Ternary complexes of copper(II), nickel(II) and zinc(II) with nitrilotriacetic acid as a primary ligand and some phenolic acids as secondary ligands

Summary The formation of ternary complexes of the MAL^3– type [where M = Cu^II, Ni^II and Zn^II ; A = nitrilotriacetic acid (NTA); L = 1-hydroxy-2-naphthoic acid (1,2 HNA) and 2-hydroxy-1-naphthoic acid (2,1 HNA)] have been studied potentiometrically in 50% v/v aqueous — ethanol (25° and µ = 0.1). Under identical conditions the binary complexes of the 1,2- and 2,1-HNA ligands have also been examined. The values of mixed ligand formation constants K_MAL have been found to be lower than K_ML (first step formation constant of binary complexes) and even less than (second step formation constant of binary complexes).     

Triazine interlinked covalent organic polymer as an efficient anti-bacterial agent

Herein, we report the synthesis of new covalent organic polymer comprising triazine and o-tolidine by solvothermal method. The formation of polymer was confirmed by Fourier transform infra red spectroscopy (FT-IR), cross polarization–magic angle spinning nuclear magnetic resonance (NMR), transmission electron microscopy, and scanning electron microscopy. Their antibacterial activity toward S. aureus (gram-positive) and P. aeruginosa (gram-negative) was assessed by the optical density measurements and direct contact method. These results have great significance toward the design of new porous polymers for antibacterial applications.     

Recent advancement in inorganic-organic electron transport layers in perovskite solar cell: current status and future outlook

Organic-inorganic lead halide perovskite solar cells have captured significant attention in recent years due to low processing costs and unprecedented development in power conversion efficiency (PCE). It has appeared from 2009 with PCE of 3.8% to being claimed more than 25.2% PCE in a very short span of time, showing their future prospective toward the fabrication of less expensive and stable solar cells. The incredible advancement in this technology encourages at one end, whereas several hurdles restricting its complete utilization for commercial purposes at another end. Although the selection of perovskite structure is limited with planar and mesoporous electron transport layers (ETLs), but identification of appropriate ETLs necessitates excellent effort to improve the surface morphology of absorber and obtain enhanced PCE with higher stability. In the present review, we have investigated various inorganic-organic ETLs with different device configurations of PSCs, primarily focusing on crystallization and morphology control techniques of ETL thin films. Numerous strategies such as surface functionalization, doping, and addition of interfacial layer are adopted for ETLs, and their effect on device efficiency, performance, and hysteresis is also discussed in detail. Additionally, designs of PSCs with different device configurations are discussed as well, providing future guidelines for significant progress in PSCs structure with different ETLs.     

Chiral Interlocked Corrole Dimers Directly Linked at Inner Carbon Atoms of Confused Pyrrole Rings

A facile synthetic strategy towards conformationally stable chiral chromophores based on dimeric porphyrinoids has been established. A peculiar class of face-to-face intramolecularly interlocked corrole dimers were formed by the oxidative C−C coupling linked at the inner carbon sites upon simple treatment of copper(II) ions. Their intrinsic electronic structures were modulated by the peripheral corrole ring annulations, which lead to distinct optical properties and redox profiles. The stereogenic carbon centers implemented in the confused corrole skeleton provided a rationale for designing novel chiral materials.     

Nanocomposite Hydrogel of Pd@ZIF-8 and Laponite®: Size-Selective Hydrogenation Catalyst under Mild Conditions

The composite hydrogel of a nanoscale metal–organic framework (NMOF) and nanoclay has emerged as a new soft-material with advanced properties and applications. Herein, we report a facile synthesis of a hydrogel nanocomposite by charge-assisted self-assembly of Pd@ZIF-8 nanoparticles with Laponite^® nanoclay which coat the surface of Pd@ZIF-8 nanoparticles. Such surface coating significantly enhanced the thermal stability of the ZIF-8 compared to the pristine framework. Further, the Pd@ZIF-8+LP hydrogel nanocomposite shows better size-selective catalytic hydrogenation of olefins than Pd@ZIF-8 nanoparticles based on selective diffusion of the substrate.     

2- and 2,7-Substituted para-N-Methylpyridinium Pyrenes: Syntheses,Molecular and Electronic Structures,Photophysical, Electrochemical,and Spectroelectrochemical Properties and Binding to Double-Stranded (ds) DNA

Two N-methylpyridinium compounds and analogous N-protonated salts of 2- and 2,7-substituted 4-pyridyl-pyrene compounds were synthesised and their crystal structures, photophysical properties both in solution and in the solid state, electrochemical and spectroelectrochemical properties were studied. Upon methylation or protonation, the emission maxima are significantly bathochromically shifted compared to the neutral compounds, although the absorption maxima remain almost unchanged. As a result, the cationic compounds show very large apparent Stokes shifts of up to 7200 cm⁻¹. The N-methylpyridinium compounds have a single reduction at ca. −1.5 V vs. Fc/Fc⁺ in MeCN. While the reduction process was reversible for the 2,7-disubstituted compound, it was irreversible for the mono-substituted one. Experimental findings are complemented by DFT and TD-DFT calculations. Furthermore, the N-methylpyridinium compounds show strong interactions with calf thymus (ct)-DNA, presumably by intercalation, which paves the way for further applications of these multi-functional compounds as potential DNA-bioactive agents.     

Ionic liquid mediated synthesis and in vitro mechanistic exploration of polycyclic cage-like heterocyclic hybrid

A three-component, [3 + 2]-cycloaddition/annulation domino protocol is described for the synthesis in excellent yield of a polycyclic cage-like heterocyclic hybrid (PCHH) that comprises various advantaged structural units viz., α,β-unsaturated ketone moiety, 4-pyridinone and pyrroloisoquinoline in a cage-like framework. The antitumor activity of PCHH on human breast (MCF7), colon (HCT116), cervical (JURKAT) and lung (NCI-H460) malignant cell lines inhibited the propagation of all cell lines. This hybrid molecule displayed increased broad-spectrum anticancer activity with higher doses of PCHH. Furthermore, the compound induced 45.21% of early apoptosis and 46.32% of late apoptosis in the Jurkat cancer cell line. Cell cycle analysis showed that this cage-like compound caused cell cycle arrest of Jurkat cells at the S phase and sub G0/G1 phase. Additionally, it led to increased DNA fragmentation and mitochondrial membrane permeabilization through activation of caspase-3 enzyme. Present investigation demonstrates the specific cytotoxic activity of the cage-like compound and the induction of apoptosis through the intrinsic pathway of Jurkat cells.     

Chemical Composition and Antioxidant Activity of the Leaf Essential Oil of Schefflera venulosa

Chemistry of Natural Compounds -     

Nickel and Tungsten Bimetallic Nanoparticles Modified Pencil Graphite Electrode: A High-performance Electrochemical Sensor for Detection of Endocrine Disruptor Bisphenol A

In this work, an economically viable, very low cost, indigenous, ubiquitously available electrochemical sensor based on bimetallic nickel and tungsten nanoparticles modified pencil graphite electrode (NiNP-WNP@PGE) was fabricated for the sensitive and selective detection of bisphenol A (BPA). The NiNP-WNP@PGE sensor was prepared by a facile electrochemical one step co-deposition method. The prepared nanocomposite was morphologically characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), electrochemically by cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The proposed sensor displayed high electrocatalytic activity towards electro-oxidation of BPA with one irreversible peak. The fabricated sensor displayed a wide detection window between 0.025 μM and 250 μM with a limit of detection of 0.012 μM. PGE sensor was successfully engaged for the detection of BPA in bottled water, biological, and baby glass samples.