Showing papers by "Ranjan K. Singh published in 2013"
TL;DR: In this article, the in situ generated new ligand (Z)-N′(1,3,4-thiadiazol-2-yl) acetimidate (tha) formed complexes [Ni(tha)2] (1), [Cu(tha), 2] (2) and [Zn(tha)-2](3) in one pot condensation reactions between metal(II) acetate and 2-amino-1, 3, 4-thIadiazole.
25 citations
TL;DR: The non-coincidence effect (NCE) of DMSO was determined for all the solvents and compared with four theoretical models such as McHale's model, Mirone's modification of McHales' model, Logan's model and Onsager-Fröhlich dielectric continuum model respectively.
24 citations
TL;DR: In this paper, a series of Schiff base calamitic liquid crystal; methyl 4-(4′-nalkoxybenzylideneamino)benzoate (MABAB), H2n+1C n OC6H4C(H)=NC6H 4COOCH3 (n = 6, 8, 10, 12, 14, 16) has been synthesized and characterised by elemental analyses, Fourier transform infrared spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectrograph
Abstract: A new series of Schiff base calamitic liquid crystal; methyl 4-(4′-n-alkoxybenzylideneamino)benzoate (MABAB), H2n+1C n OC6H4C(H)=NC6H4COOCH3 (n = 6, 8, 10, 12, 14, 16) has been synthesised and characterised by elemental analyses, Fourier transform infrared spectroscopy (FT-IR), 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopy. The mesomorphic properties of these compounds were studied by differential scanning calorimetry (DSC) and polarising optical microscopy (POM). All members of the series exhibit enantiotropic smectic A (SmA) mesophase. Temperature-dependent micro-Raman study of one of the members, MABAB-10 has been employed to identify phase transitions and the molecular rearrangement therein. Analysis of Raman marker bands; C–H in-plane bending, C–C stretching of phenyl rings and –C(H)=N– linking group of core confirms the transitions clearly as observed through DSC and POM. An in situ Raman measurement of C–H in-plane bending mode has also been performed to visualise the molecular changes m...
22 citations
TL;DR: DNA fragmentation data suggest apoptosis as one of the protective mechanisms of HEAM as well as anti-carcinogenic and immunomodulatory effects of A. marmelos hydroalcoholic extract indicate potential beneficial effects in cancer therapy.
Abstract: Context and objective: Tobacco smoke and nitrostable foods containing N-methyl N-nitrosourea (MNU) are among the primary causes of liver cancer. To substantiate the beneficial claims ascribed to Aegle marmelos (L.) Correa (Rutaceae), the hepatoprotective potential of its leaf extract was studied using an MNU-induced hepatocarcinogenesis model in Balb/c mice.Materials and methods: After dose selection, 40 mice were randomly assigned to 4 groups: I (control), II (intraperitoneally (i.p.) primed with 50 mg/kg MNU), III (100 mg/kg A. marmelos hydroalcoholic extract (HEAM) i.p.) and IV (MNU + HEAM, i.p.). Inflammatory (IL-1β, IL-6), anti-inflammatory (IL-4) cytokine expression, apoptosis (Bcl-2) and tumor-related (p53, c-jun) genes were assessed at mRNA level. HEAM effects on hematological parameters were examined.Results and discussion: HEAM treatment decreased IL-1β, IL-6, Bcl-2 and c-jun respectively expressions by 90, 25, 53 and 30%, respectively. p53 and IL-4 expression was up-regulated by 1.5- an...
19 citations
TL;DR: Proton transfer required for the formation of the zwitterionic form of SAR was found to occur when the number of water molecules in the first hydration shell was six or more.
16 citations
TL;DR: In this article, a new liquid crystalline material containing diester linking group ethyl-[4-(4′-decyloxy)benzoyloxy]-benzoate (4-EDBB) was synthesized.
15 citations
TL;DR: In this paper, the structure of compounds 1, 2 and 3 are stabilized via intramolecular as well as intermolecular hydrogen bonding and crystallize in monoclinic system with space group P 1, P21/n and P 1.
12 citations
TL;DR: The Raman spectra of a liquid crystalline system, 4-Decyloxy benzoic acid (4DBA) have been recorded at different temperatures within the interval 300-78 K in order to identify the structural changes in crystalline state of a nematogen and to understand the molecular alignment therein.
11 citations
TL;DR: The Raman, IR and DFT study confirm that Cu metal has good binding affinity to the isolated adenine base.
9 citations
TL;DR: In this paper, the effect of methylation on the Pmd ring has been studied in terms of wavenumber shift (Δ ν ), peak-position and linewidth variation with mole fraction of the solvent.
9 citations
01 Jan 2013
TL;DR: In this article, the structure of compounds 1, 2 and 3 are stabilized via intramolecular as well as intermolecular hydrogen bonding and crystallize in monoclinic system with space group P 1, P21/n and P 1.
Abstract: New compounds 5-benzyl-N-phenyl-1,3,4-thiadiazol-2-amine (Bptha, 1), 2-(5-phenyl-1,3,4-thiadiazol2-yl) pyridine (Pthp, 2) and 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (Mtmth, 3) have been synthesized and characterized with the aid of elemental analyses, IR, NMR and single crystal X-ray data. The structure of compounds 1, 2 and 3 are stabilized via intramolecular as well as intermolecular hydrogen bonding and crystallize in monoclinic system with space group P 1, P21/n and P 1, respectively. During the course of reaction, the substituted thiosemicarbazide/thiohydrazide get cyclized into the corresponding thiadiazole in the presence of manganese(II) nitrate via loss of H2O to yield compounds 1 and 2. However condensation occurred in the case of 5-methyl-1,3,4-thiadiazole-2-thiol which yielded 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (3) by loss of one mole of H2S from two moles of 5-methyl-1,3,4-thiadiazole-2-thiol in the presence of manganese(II) acetate. The geometry optimization has been performed using DFT method and geometrical parameters thus obtained for the compounds have been compared with their single crystal X-ray data. The negative values of HOMO and LUMO energies for the molecules indicate that they are stable. The electronic transition from the ground state to the excited state due to a transfer of electrons from the HOMO to LUMO levels is mainly associated with the p ��� p transition.