Thin-Layer Chromatographic Enantioseparation of (RS)-Etodolac Using Indirect Approach

JPC – Journal of Planar Chromatography – Modern TLC - Enantioseparation of (RS)-etodolac was achieved by an indirect approach. Extraction of the drug (RS)-etodolac (Etd) was done from...     

[bmim]OH: An efficient catalyst for the synthesis of mono and bis spirooxindole derivatives in ethanol at room temperature

A rapid and efficient, one pot synthesis of spirooxindole derivatives has been attempted by threecomponent reaction of isatin, malononitrile and carbonyl compound possessing a reactive α-methylene group by using task specific ionic liquid, 1-butyl-3-methyl imidazolium hydroxide [bmim]OH as a catalyst. The important features of this methodology are straight forward route in short reaction time at room temperature and avoid any hazardous organic solvent, toxic catalyst, tedious purification step. Interestingly, this protocol is not only limited to mono-systems but also to the synthesis of newer bisspirooxindole system. The separation of the product and reusability of the catalyst are easy with excellent yield. The [bmim]OH catalyst system could be reused up to five recycles without appreciable loss of activity.     

Synthesis,anticancer screening,and in silico ADME prediction of novel 2-pyridones as Pim inhibitors

A novel series of 26 substituted N-(2-ethylphenyl)-2-oxo-pyridine-3-carbonitriles have been designed and synthesized via one-pot synthesis of various aromatic aldehydes, different aromatic acetophenones, and 2-cyano-N-(2-ethylphenyl)acetamide 1 . Moreover, cytotoxicity of the target compounds was evaluated by NCI, which selected 14 compounds for one-dose screening. Among them, compound 21 was selected for five-dose screening, which confirmed its potency against most of cancer cell lines. This compound elicited selectivity profile against human cell line WI-38. Cell cycle analysis was carried out, revealed that compound 21 is an apoptosis inducer causing cell cycle arrest at G2/M. Further exploration on the mode of action by evaluating its effect against Pim-1, Pim-2, and Pim-3 demonstrated its inhibitory effect on Pim-1 and Pim-3 rather than Pim-2. Molecular docking showed that compound 21 binds with high affinity to the active site of Pim-1 enzyme through three hydrogen bonds and two arene-H bonds.     

Charge Carrier Transport 1n 1:1 Complexes of Tetracyanobenzene with Naphthalene Anthracene and Durene

Abstract

It is well established that crystals of charge transfer (CT) complexes formed between aromatic donors and acceptors are built up of linear stacks of closely packed molecules. There are two main types of CT crystal structure, (i) a parallel arrangement of linear stacks made up of the individual component molecules, AAAA…DDDD… and (ii) a parallel arrangement of linear stacks made up of alternating molecules, ADADA… In each case it is to be expected that the intermolecular forces between the face to face packed molecules in each stack are far greater than those forces between stacks. A considerable anisotropy in physical properties which are a strong function of intermolecular interactions is a natural result of these crystal structures. Such anisotropy has been reported in the few crystals of the ADAD structure which have been examined, for example, in triplet exciton motion in biphenxl² and anthracene tetracyanobenzene (TCNB) complexes³,⁴ and in charge carrier mobilities μ in anthracene⁵ and phenthrene-pyromellitic-acid-dianhydride⁶ as well as anthracene-trinitrobenzene⁷. Carrier mobilities which were reported were all low, < 0.1 cm²/V sec., and though the major interesting questions were posed, such as what is the effect of different donors on μ?; or are there separate conduction and valence bands for acceptors and donors?; the dearth of mobility data on a range of materials leaves these questions unanswered. We have recently measured the mobilities of holes in several TCNB complexes as a first step towards understanding carrier transport in such materials. These are a particularly interesting series of materials in that triplet motion is said to be primarily two dimensional in anthracene TCNB³, and unidimensional in biphenyl TCNB². Since the transport of charge, like triplet exciton motion, is dominated by exchange interactions, and since CT triplet     

Evidence of a ZnCr2Se4 spinel inclusion at the core of a Cr-doped ZnSe quantum dot

Herein we report doping of ZnSe by Cr ions leads to formation of small ZnCr(2)Se(4) spinel inclusions within the cubic sphalerite lattice of a 2.8 nm CrZnSe quantum dot (QD). The Cr ion incorporates as a pair of Cr(III) ions occupying edge-sharing tetragonal distorted octahedral sites generated by formation of three Zn ion vacancies in the sphalerite lattice in order to charge compensate the QD. The site is analogous to the formation of a subunit of the ZnCr(2)Se(4) spinel phase known to form as inclusions during peritectoid crystal growth in the ternary CrZnSe solid-state compound. The oxidation state and site symmetry of the Cr ion is confirmed by X-ray absorption near edge spectroscopy (XANES), crystal field absorption spectroscopy, and electron paramagnetic resonance (EPR). Incorporation as the Cr(III) oxidation state is consistent with the thermodynamic preference for Cr to occupy an octahedral site within a II-VI semiconductor lattice with a half-filled t(2g) d-level. The measured crystal field splitting energy for the CrZnSe QD is 2.08 eV (2.07 eV form XANES), consistent with a spinel inclusion. Further evidence of a spinel inclusion is provided by analysis of the magnetic data, where antiferromagnetic (AFM) exchange, a Curie-Weiss (C-W) temperature of θ = -125 K, and a nearest-neighbor exchange coupling constant of J(NN) = -12.5 K are observed. The formation of stable spinel inclusions in a QD has not been previously reported.     

Structurally diverse copper(II) complexes of polyaza ligands containing 1,2,3-triazoles: site selectivity and magnetic properties

Copper(II) acetate mediated coupling reactions between 2,6-bis(azidomethyl)pyridine or 2-picolylazide and two terminal alkynes afford 1,2,3-triazolyl-containing ligands L(1)-L(6). These ligands contain various nitrogen-based Lewis basic sites including two different pyridyls, two nitrogen atoms on a 1,2,3-triazolyl ring, and the azido group. A rich structural diversity, which includes mononuclear and dinuclear complexes as well as one-dimensional polymers, was observed in the copper(II) complexes of L(1)-L(6). The preference of copper(II) to two common bidentate 1,2,3-triazolyl-containing coordination sites was investigated using isothermal titration calorimetry and, using zinc(II) as a surrogate, in (1)H NMR titration experiments. The magnetic interactions between the copper(II) centers in three dinuclear complexes were analyzed via temperature-dependent magnetic susceptibility measurements and high-frequency electron paramagnetic resonance spectroscopy. The observed magnetic superexchange is strongly dependent on the orientation of magnetic orbitals of the copper(II) ions and can be completely turned off if these orbitals are arranged orthogonal to each other. This work demonstrates the versatility of 1,2,3-triazolyl-containing polyaza ligands in forming metal coordination complexes of a rich structural diversity and interesting magnetic properties.     

Synthesis,Spectroscopic Characterization,Thermogravimetric and Biological Activity Evaluation of Te(Ⅳ),Se(Ⅳ),V(Ⅲ),Nb(Ⅴ),Ta(Ⅴ)Complexes With Indole-3-Acetic Acid Plant Hormone Ligand

Te(Ⅳ), Se(Ⅳ), V(Ⅲ), Nb(Ⅴ) and Ta(Ⅴ) complexes of indole-3-acetic acid (IAAH) ligand were synthesized, characterized by elemental analysis and various spectroscopic techniques like, IR, 1H-NMR, X-ray powder diffraction, UV-Visible, thermogravimetry analysis, magnetic measurements, molar conductance and surface morphology using SEM. All the synthesized complexes of IAAH ligand have 1∶2 stoichiometry of the types [Te(IAA)₂(NH₃)₂]·2Cl (Ⅰ), [Se(IAA)₂(NH₃)₂]·2Cl (Ⅱ), [V(IAA)₂(NH₃)(Cl)] (Ⅲ), [Nb(IAA)₂(Cl)₃] (Ⅳ), and [Ta(IAA)₂(Cl)₃] (Ⅴ). Spectral analysis indicates octahedral geometry for the Te(Ⅳ), Se(Ⅳ) and V(Ⅲ) complexes, whereas both Nb(Ⅴ) and Ta(Ⅴ) have a seven-coordination. The bonding sites are the oxygen atoms of carboxylate group for the deprotonated indole-3-acetic acid (IAA) ligand. The thermogravimetry analysis studies gave evidence for the presence of other coordinated molecules (Cl or NH₃) in the composition of IAA complexes, which were further supported by IR and micro analytical measurements. The higher molar conductance data of tellurium and selenium (Ⅳ) complexes reveal that these chelates are electrolytes, while low conductivity values for the vanadium(Ⅲ), niobium and tantalum(Ⅴ) chelates indicated a non-electrolytes. To test the antibacterial property of the five complexes in this study, four bacterial strains Klebsiella (G-), Escherichia coli (G-), Staphylococcus aureus (G+) and Staphylococcus epidermidis (G+) were used in the investigation. The effects of the five complexes in the cytotoxicity of Caco-2 and Mcf-7 human cancer cell lines were studied Neutral red uptake assay for the estimation of cell viability/cytotoxicity protocol.     

Comparison of optical properties of periodic photonic–plasmonic and randomly textured back reflectors for nc-Si solar cells

Light trapping is essential to harvest long-wavelength red and near-infrared photons in thin film silicon solar cells. Light trapping in p-i-n thin film cells is commonly achieved with back-reflectors, and in n-i-p cells with textured front transparent conductors. We systematically compare the optical properties and performance of randomly roughened back reflectors with periodic plasmonic-photonic back-reflectors in p-i-n solar cells. The randomly textured back reflectors were prepared to have very high diffuse reflectance comparable to the state of the art. The periodic back reflectors of tapered nano-pillars/bumps show enhanced quantum efficiency and optical absorption over randomly structured back reflectors using the same solar cell architecture in nc-Si solar cells. The strong diffraction and light concentration in periodic back reflectors may be more beneficial than the light scattering offered by randomly textured back reflectors.