Synthesis of novel cone-configurated hexa-tert-butyl-trimethoxy-calix[6]arenes bearing tris(bipyridyl) pendants and their use in recognition and ionic speciation

A series of novel cone-configurated p-tert-butyl-trimethoxycalix[6]arenes bearing three 2,2′-bipyridyl units at their lower rim have been synthesized. The ¹H NMR and ¹³C NMR spectra of synthesized derivatives revealed that the ring inversion in calix[6]arene could be suppressed by the introduction of three 2,2′-bipyridyl moieties at the lower rim of calix[6]arene scaffold which fixes it into its cone configuration. The complexation ability of the synthesized receptors (5a–d) towards Fe(II) ion was investigated by UV-Visible titration to reveal that the synthesized receptors interact with Fe(II) in a 1:1 binding stoichiometry and respond to a specific oxidation state of the metal ion. The observations have significance for studies directed at the design of molecular receptors for ionic speciation through molecular recognition.     

Design,synthesis, preliminary pharmacological evaluation,and docking studies of pyrazoline derivatives

Ten derivatives of N1 substituted/unsubstituted 5-(4-chlorophenyl)-3-(2-thienyl) pyrazoline were synthesised from chalcone-like intermediate and substituted phenyl hydrazines, hydrazine hydrate, and semi/thiosemicarbazide. The chemical structure of compounds was confirmed by means of IR, ¹H NMR, mass spectroscopy, and elemental analysis. The antidepressant and anticonvulsant activities were investigated by Porsolt’s behavioural despair test (forced swimming) and maximum electroshock seizure test, respectively. Rota-Rod test was performed to assess any probable changes in motor coordination induced by the test compounds. Four compounds (IId, IIg, IIi, and IIj) exhibited good activity profile against depression and docking studies confirmed their consensual interaction with monoamine oxidase A. In addition, compounds IIc and IIe showed protection against MES-induced seizures.     

Breakup of 42 MeV 7Li projectiles in the fields of 12C and 197Au nuclei

Inclusive cross sections of α particles and tritons from the breakup of 42 MeV ⁷Li by ¹²C and ¹⁹⁷Au targets are presented and analysed in the framework of the Serber model. Spectral distortions due to the targets and relevant reaction mechanisms are discussed.     

Microcomputer-based simulation of heat conduction between solid of tapered shape and the fluid

Simulating the heat conduction in between a solid conducting body immersed in fluid at a given temperature is a difficult task, particularly when the body is tapered in shape and the costs have to be kept low. The body in question is cylindrical, symmetrical about z-axis, tapered in shape and has been heated to a high temperature before being immersed into the fluid. The heat conduction equation in cylindrical polar coordinates with all derivative boundary conditions is attempted to be solved in two ways – first analytically making use of Bessel's function and then by numerical modelling with the help of Finite Difference method, and equations thus formed have been solved through ADI explicit and Implicit (Peaceman Rachford) scheme on microcomputer. The paper is an account of work already done on this and includes further possibilities for general solution with analytical methods and a suitable low-cost numerical solution. Also possible analogy with flow of fluids have been explored. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Intercalation Compounds of Cu2+ and Nl2+ — Exchanged Montmorillonite Clay with 8-Hydroxyquinoline

Montmorillonite clay mineral shows remarkable ion exchange, intercalation and swelling properties. It can act as a good host for large organic molecules. Intercalated coordination compounds can be prepared in the interlayer spaces of montmorillonite structure. Cu(II)- and Ni(II)- exchanged montmorillonite sorb 8-hydroxyquinoline (oxine) to form corresponding coordination compounds of the exchanged metal ions. Such compounds have been characterised by means of elemental analysts, infrared spectroscopy, magnetic susceptibility data and X-ray diffraction. These compound show good thermal stability.     

Extraction of gold(III) from low-grade ores with amidines followed by its spectrophotometric determination with methylene blue

A procedure is described in which gold(III) is quantitatively extracted with an amidine into chloroform over the acidity range pH 3.0–11.0 M HCl, followed by its selective spectrophotometric determination by interaction of the extract with methylene blue in the pH range 3.0–9.0. The molar absorptivity of the coloured complex formed by extraction with ten different amidines and methylene blue reaction lie in the range 1.1 × 10⁴?6.5 × 10⁴ 1 mol^?1 cm^?1 at λ_max (650 nm) in chloroform. The simplest compound, N, N′-diphenylbenzamidine, was chosen for detailed study. The limit of detection is 5 μg Au l^?1. The method is free from interferences from the metals that are generally associated with gold. The method is simple, reproducible and applicable to the accurate recovery of gold from low-grade ores containing the metal at levels of > 1.5 μg g^?1.     

Sugarcane Bagasse Ash-Based Silica-Supported Boric Acid (SBA-SiO2-H3BO3): A Versatile and Reusable Catalyst for the Synthesis of 1,4Dihydropyrano[2,3c]pyrazole Derivatives

Russian Journal of Organic Chemistry - A simple, green, and efficient protocol has been developed for the synthesis of biologically active 1,4dihydropyrano[2,3c]pyrazole derivatives via one-pot...     

Synthesis,spectral characterization,thermal study and antimicrobial activity of (E)-4-(substituted 1-Benzo[d]imidazole-2-yl)-N'-(substituted Benzylidene)benzohydrazide schiff bases

Antimicrobial properties casing wide applicability in water detoxification, pharmaceutics and in industries. Present work focus on the synthesis of a new series of Schiff Bases (E)-4-(1 substituted-1H Benzo[d]imidazole-2-yl)-N'-(substituted Benzylidene)benzohydrazide (5a-5l) were synthesized. The convenient route for the synthesis of new analogues by the condensation of 4-(substituted -1H-Benzo[d]imidazole-2-yl)-N'- Hydrazine with different derivatives of aromatic aldehydes were described using different solvents and catalysts. The structures of the synthesized compounds were ascertain by spectral techniques viz. IR, ¹H NMR, MS and Physical Elemental data. Compounds were also subjected to thermal analysis to study their physical and chemical properties. The title compounds were also screened for their antimicrobial activity against various bacterial & Fungal strains. Results of bioassay vary with diverse group attached to Benzimdazole motif and could be helpful for the development of other bioactive molecules.     

Polyamidoamine dendrimer and dextran conjugates: preparation,characterization, and in vitro and in vivo evaluation

Amide and ester conjugates of aceclofenac with polyamidoamine (PAMAM-G0) dendrimer zero generation and dextran (40 kDa) polymeric carrier, respectively, are presented. The prepared conjugates were characterized by UV, TLC, HPLC, IR, and ¹H NMR spectroscopy. The average degrees of substitution of amide and ester conjugates were determined and found to be (12.5 ± 0.24) % and (7.5 ± 0.25) %, respectively. The in vitro hydrolysis studies showed that dextran ester conjugate hydrolyzed faster in a phosphate buffer solution of pH 9.0 as compared to PAMAM dendrimer G0 amide conjugate, and followed the first order kinetics. No amount of the drug was regenerated at pH 1.2 in simulated gastric fluid. The dextran conjugate showed short half-life as compared to the PAMAM dendrimer conjugate. Anti-inflammatory and analgesic activities of the dendrimer conjugate were found to be similar to those of the standard drug. Results of chronic ulceroginic activity showed deep ulceration and high ulcer index for aceclofenac, whereas lower ulcer index was found for the PAMAM dendrimer and dextran (40 kDa) conjugates. Experimental data suggest that PAMAM dendrimer and dextran (40 kDa) can be used as carriers for the sustained delivery of aceclofenac along with a remarkable reduction in gastrointestinal toxicity.     

Photoconductivity and photoluminescence in chemically deposited films of (Cd0.95-Pb0.05)S: CdCl2,Ce

The results of photoconductivity (PC), photoluminescence (PL), optical absorption spectra, XRD and SEM studies are presented for (Cd_0.95-Pb_0.05)S: CdCl₂,Ce films prepared by chemical bath deposition technique. PC gains ∼10⁷ are found in doped films. PL emission spectrum is found in red region which is related to 5d to 4f transition in Ce. Films prepared at 60°C show better PC while those prepared at room temperature (RT) show better PL. Optical absorption studies show reduction in band gap due to addition of PbS. A peak due to Ce is also observed in absorption spectrum. XRD studies show the presence of both CdS and PbS. SEM studies show presence of microcrystals, cluster of grains along with some rod type structures.