Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Catalysis & Excited state. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Synthesis, structural characterization, and photophysical, electrochemical, intercomponent energy-transfer, and anion-sensing studies of imidazole 4,5-bis(benzimidazole)-bridged Os(II)Os(II) and Ru(II)Os(II) bipyridine complexes.

Abstract: Homo- and heterobimetallic complexes of composition [(bpy)2MII(H2Imbzim)M′II(bpy)2](ClO4)3·nH2O, where MII = M′II = Os (1), MII = Ru and M′II = Os (2), H3Imbzim = 4,5-bis(benzimidazole-2-yl)imidazole, and bpy = 2,2′-bipyridine, have been synthesized and characterized using standard analytical and spectroscopic techniques. Both of the complexes crystallized in monoclinic form with the space group P21/m for 1 and P21/n for 2. The absorption spectra, redox behavior, and luminescence properties of the complexes have been thoroughly investigated. The complexes display very intense, ligand-centered absorption bands in the UV region and moderately intense metal-to-ligand charge-transfer (MLCT) bands in the visible region. The bimetallic complexes show two successive one-electron reversible metal-centered oxidations. The strong fluorescence of free H3Imbzim is completely quenched in the metal complexes by energy transfer to the metal-based units, which exhibit their characteristic MLCT phosphorescence. The lumine...

Ultrasonic Investigation on Ferroelectric BaTiO3 Doped 80V2O5—20PbO Oxide Glasses

Abstract: The frequency dependent ultrasonic velocities (both longitudinal and shear) and attenuation in BaTiO 3 doped (80V 2 O 5 -20PbO + x BaTiO 3 ) oxide (VPB) glasses (for x = 0, 1, 5, 10, and 15 wt% of the base glass) have been measured using pulse echo overlap method at room temperature. From the measured velocity, density and attenuation, various parameters namely longitudinal, shear, bulk, and Young's moduli, Debye temperature, Poisson's ratio, acoustic impedance and microhardness of the VPB glasses were determined. All these parameters of the glasses increase with addition of BaTiO 3 content. On the other hand, attenuation decreases with addition of BaTiO 3 The variation of these parameters with the addition of BaTiO 3 content was discussed in terms of the change in structure of the glass network. The study reveals that ultrasonic velocity and attenuation measurements have been effectively used as a tool to explore the structural changes and mechanical properties on addition of BaTiO 3 in vanadate lead glasses.

A new hexaaza bicyclic cyclophane with dual binding sites.

Abstract: A new C3-symmetric drum-shaped homoditopic haxaamino bicyclic cyclophane and its hexachloride and hexaiodide complexes have been synthesized and characterized and dual recognition of guests has been demonstrated. Single-crystal X-ray analysis illustrates that bicyclic cyclophane has a cavity and side pockets for acetone molecules. The hexaprotonated state of this bicycle shows encapsulation of an iodide inside its cavity, and in hexachloride complex, chloride is recognized as Cl(-)...H2O in each of the three side pockets which are in extensive hydrogen bonding interactions with the water and chlorides. (1)H NMR experiments have also been carried out on hexatosylated cyclophane with the halides to study solution state binding.

Maxwell–Wagner polarization mechanism in potassium and titanium doped nickel oxide showing giant dielectric permittivity

Abstract: KxTiyNi1−x−yO(x = 0.05–0.3, y = 0.02–0.25) ceramics (abbreviated as KTNO) have been synthesized showing high permittivity. All the KTNO samples of varying compositions exhibit high dielectric permittivity (~104) near room temperature, which is comparable to that of the recently discovered CaCu3Ti4O12 (CCTO) ceramic. The high dielectric constant of KTNO depends on both the K and Ti content and can be attributed to the Maxwell–Wagner polarization mechanism and to a thermally activated mechanism.