Phosphorus Schiff base ligand and its complexes: Experimental and theoretical investigations

A phosphorus-containing Schiff base was prepared from bis{3-[2-(4-amino-1,5-dimethyl-2-phenylpyrazol-3-ylideneamino)ethyl]indol-1-ylmethyl}phosphinic acid and paraformaldehyde as a novel antibacterial compound. The reaction of the Schiff base ligand with VO(IV), Ni(II), Co(II), Cu(II), Zn(II), Cd(II), Hg(II), Pd(II) and Pt(IV) led to binuclear species of metal complexes, depending on the ratio of metal ion and ligand. The ligand and its complexes were investigated using elemental analysis, Fourier transform infrared, ¹H NMR, ¹³C NMR, UV–visible and mass spectra, thermogravimetric analysis, conductivity measurements and thermal analysis. The results showed that the Schiff base behaves as a tetradentate ligand; moreover, on the basis of conductance results, of all the prepared complexes are non-electrolytes, excepting the Pt(IV) complex. The metal complexes were found to be formed with a metal-to-ligand ratio of 2:1, except for the Pt(IV) complex with a ratio of 1:1. The activation thermodynamic parameters (ΔE*, ΔH*, ΔS*, ΔG* and K) and the activation energy of thermal decomposition were determined from thermogravimetric analysis using the Coats–Redfern method. The biological activities of the metal complexes were screened against the growth of bacteria and fungi in vitro to assess the antimicrobial potential and study the toxicity of the compounds. The prepared compounds have noteworthy antimicrobial properties.     

Synthesis and biological evaluation of an indole core-based derivative with potent antimicrobial activity

Research on Chemical Intermediates - Dibenzenesulphonyl diethyl amine has been prepared and used as a starting material to be introduced as an alkylating agent. Reaction of dibenzenesulphonyl...     

Simple Electrochemical Characterization of ortho‐Carborane and some of its exo‐Skeletal Derivatives

Electrochemical behaviour of 12 icosahedral carboranes – ortho‐, meta‐ and para‐carborane with different exo‐skeletal substituents was investigated. The study was done using phosphate buffers, in some cases with 20 % and 30 % dimethyl sulfoxide (DMSO) addition to increase the solubility of studied compounds. Commercial glassy carbon electrode or home‐made screen printed electrodes were used. Distinct electrochemical responses were observed only for the ortho‐carborane and its exo‐skeletal derivatives. The study of different exo‐skeletal substituents on the electrochemical behaviour of the carboranes is crucial for the intended use of these compounds as electrochemical labels of biomolecules.     

The electrochemistry of some ferrocene derivatives: redox potential and substituent effects

Fifteen ferrocene derivatives I–IX (four of which have been prepared for the first time: II, IIIf, V and VIII) have been prepared by Friedel–Crafts acetylation, Claisen condensation, Michael reaction, and ring closure by hydrazine hydrate. The anodic behaviour of these compounds has been studied by cyclic voltammetry at a platinum electrode in an aprotic solvent. All these substituted ferrocenes exhibit a reversible one‐electron oxidation reduction centred at each iron centre, and the effect of substituents on the half‐wave oxidation potential is discussed in terms of their electronic properties. Linear correlations have been observed between these potentials and the Hammett σ_x constant for the substituents. Cyclic voltammetry has been carried out for ferrocene derivatives IIIa, V and IX. Copyright © 2003 John Wiley & Sons, Ltd.     

Novel Synthesis of 1H‐Inden‐1‐Ones and Thienylpropenones in Aqueous Medium

Condensation of acetylacetone with 4‐methoxybenzaldehyde, 2,4‐dimethoxybenzaldehyde, 3,4‐dimethoxybenzaldehyde, 4‐nitrobenzaldehyde and 2,4‐dinitrobenzaldehyde in water and in the presence of cetyltrimethylammonium bromide (CTABr) as cationic surfactant in dilute sodium hydroxide at room temperature did not afford the expected arylideneacetylacetone but yielded 1H‐inden‐1‐one derivatives 1 , while, with piperonaldehyde under the same conditions afforded dipiperonylideneacetone 2 . Also 3‐acetylthiophene condensed with some aromatic aldehydes under the same conditions gave the expected stereoselective thienylpropenones 4 . The structures of the products were identified by IR, NMR, Mass spectral data and elemental analysis.     

The Essential Oil-Bearing Plants in the United Arab Emirates (UAE): An Overview

Essential Oils (EOs) are expensive hydrocarbons produced exclusively by specific species in the plant kingdom. Their applications have deep roots in traditional herbal medicine, which lacks scientific evidence. Nowadays, more than ever, there is a growing global interest in research-based discoveries that maintain and promote health conditions. Consequently, EOs became a much attractive topic for both research and industry, with revenues reaching billions of dollars annually. In this work, we provide key guidance to all essential oil-bearing plants growing in the United Arab Emirates (UAE). The comprehensive data were collected following an extensive, up-to-date literature review. The results identified 137 plant species, including indigenous and naturalized ones, in the UAE, citing over 180 published research articles. The general overview included plant botanical names, synonyms, common names (Arabic and English), families and taxonomic authority. The study acts as a baseline and accelerator for research, industry and discoveries in multiple disciplines relying on essential oil-bearing plants.     

Quasi-symmetric 2-(28, 12, 11) designs with an automorphism of order 7

All quasi-symmetric 2-(28, 12, 11) designs with an automorphism of order 7 without fixed points or blocks are enumerated. Up to isomorphism, there are exactly 246 such designs. All but four of these designs are embeddable as derived designs in symmetric 2-(64, 28, 12) designs, producing in this way at least 8784 nonisomorphic symmetric 2-(64, 28, 12) designs. The remaining four 2-(28, 12, 11) designs are the first known examples of nonembeddable quasi-symmetric quasi-derived designs. These symmetric 2-(64, 28, 12) designs also produce at least 8784 nonisomorphic quasi-symmetric 2-(36, 16, 12) designs with intersection numbers 6 and 8, including the first known examples of quasi-symmetric 2-(36, 16, 12) designs with a trivial automorphism group. © 1998 John Wiley & Sons, Inc. J Combin Designs 6: 213–223, 1998     

Seventeen new 14- and 15-crown-formazans: their synthesis and evaluation in spectrophotometric determination of lithium

A number of new crown-formazans with 14 and 15 membered rings have been synthesized, characterized and investigated as selective spectrophotometric chelating agents for lithium. The effect of sodium ion concentration on the background lithium signal was studied. A comparative study for the sensitivity of these new crown-formazans in spectrophotometric determinations was studied and compared with those reported previously. The three new 14- and 15-crown-formazans 4a–c containing the pyridyl N-oxide at the formazyl carbon showed the highest selectivity to lithium determination in the presence of sodium ion.     

Synthesis and biological activity of some 3-(4-(substituted)-piperazin-1-yl)cinnolines

A new series of 6-substituted-4-methyl-3-(4-arylpiperazin-1-yl)cinnolines 8-10 were synthesized as potential antifungal agents via intramolecular cyclization of the respective 1-(2-arylhydrazono)-1-(4-arylpiperazin-1-yl)propan-2-ones 5-7, mediated by polyphosphoric acid (PPA). The amidrazones themselves were synthesized via direct interaction of the appropriate hydrazonoyl chlorides 4a-d with the corresponding N-substituted piperazine in the presence of triethylamine. The structures of the new prepared compounds were confirmed by elemental analyses, (1)H-NMR, (13)C-NMR, and ESI-HRMS spectral data. The antitumor, antibacterial, and antifungal activity of the newly synthesized compounds was evaluated.