Displacement Reaction Using Ibuprofen in a Mixture of Bioactive Imidazole Derivative and Bovine Serum Albumin—a Fluorescence Quenching Study

The mutual interaction of imidazole derivative (PIPP) with bovine serum albumin (BSA) was investigated using photoluminescent studies. The fluorescence quenching mechanism of BSA by PIPP was analyzed and the binding constant was calculated. The binding distance between PIPP and BSA was obtained based on the theory of Forester’s non-radiation energy transfer. Displacement experiments were performed by using ibuprofen to identify PIPP binding site in BSA. The effect of some common ions on the binding constant between PIPP and BSA was also examined.     

Evidence for Strong Mixing Between the LC and MLCT Excited States in Some Heteroleptic Iridium (III) Complexes

The synthesis, structure and photophysical properties of series of new luminescent cyclometalated Iridium (III) complexes are reported. The cyclometalated ligand used here is 2-aryl imidazole and the auxiliary ligand is acetyl acetone (acac). The crystal structure of the complex (dmdpi)₂Ir(acac) (5) show that the Iridium(III) ion resides in a distorted octahedral environment. All complexes exhibit bright photoluminescence (PL) at room temperature and (fpdmdmpi)₂Ir(acac) 4 has a high solution PL quantum efficiency of 0.56. The role played by electron releasing and electron withdrawing substituents of the 2-arylimidazole ligands towards the stability of HOMO and how the substituent influences the luminescent behaviour are discussed. Furthermore those substituents have effect on the contribution to mixing between ³(π-π*) and ³(MLCT) for the lowest excited states.     

Iridium(III) Complexes with Orthometalated Phenylimidazole Ligands Subtle Turning of Emission to the Saturated Green Colour

A series of novel six iridium complexes (1–6) bearing two substituted phenylimidazole and an additional acetylacetone as the third co-auxilary ligand are reported. The lowest absorption band for all iridium complexes consist of a mixture of heavy atom Ir(III) enhanced ³MLCT and ³ π-π* transitions and the phosphorescent peak wavelength can be fine-tuned to cover the spectral range 455–518 nm with high quantum efficiencies. The peak wavelength of the dopants can be finely tuned depending upon the electronic properties of the substituents. On the basis of onset potentials of the oxidation and reduction, the HOMO-LUMO energies were calculated and the reported iridium complexes emit green light with exceeding higher efficiency.     

An Intramolecular Charge Transfer Fluorescent Probe: Synthesis,Structure and Selective Fluorescent Sensing of Cu<Superscript>+2</Superscript>

A series of substituted imidazoles have been synthesized in very good yield under solvent free condition by grinding 1,2-diketone, aromatic aldehyde and ammonium acetate in the presence of molecular iodine as the catalyst. The short reaction time, good yield and easy workup make this protocol practically and economically attractive and characterized by NMR spectra, X-ray, mass and CHN analysis. An excited state intramolecular proton transfer (ESIPT) process in hydroxy imidazoles (dpip and dptip) have been studied using emission spectroscopy and it was detected that the two distinct ground state rotamers are responsible for the normal and the tautomer emissions. DFT calculations on energy, dipole moment, charge distribution of the rotamers in the ground and excited states of the imidazole derivatives were performed and discussed. DFT analysis about HOMO, HOMO-1, LUMO and LUMO + 1 were carried out and discussed. PES calculation indicates that the energy barrier for the interconversion of two rotamers is too high in the excited state than the ground state.     

Preparation and properties of Zn<Subscript>0.9</Subscript>Ni<Subscript>0.1</Subscript>O diluted magnetic semiconductor nanoparticles

With a view to study the structural, electronic, magnetic, and electrical properties of Zn_0.9Ni_0.1O diluted magnetic semiconductor nanoparticles, systematic investigation has been undertaken. Samples were prepared for the first time by hydrazine-assisted polyol method, and the powders were annealed at various temperatures in order to obtain the samples with different grain sizes. From the Rietveld refined XRD data, lattice parameters, the average crystallite size values, and r.m.s micro-strain values were computed. From the AFM and TEM studies, the average particle sizes were obtained and are found to be in the range 12–46 nm. XPS measurements clearly indicate that the chemical states as +2 for both Zn and Ni ions and are stable with varying annealing temperature. Further, using XPS and optical studies, the electronic structure of the materials was analyzed. A careful phase analysis of the Rietveld refined XRD data (at logarithmic scale) selected area electron diffraction patterns, FTIR, Raman, and XPS studies; it was concluded that all the samples are having hexagonal wurtzite structure without any detectable impurity phases. The optical band gap values are found to exhibit a clear blue shift. The influence of oxygen vacancies on the emission spectra was studied by Photo Luminescence measurement. The magnetization studies were undertaken by VSM, MFM, and FMR techniques and confirmed the presence of clear room temperature ferromagnetism without any magnetic clusters. The carrier concentration (n) values obtained from the thermo power studies are found to decrease with increasing annealing temperature and depend on the local defects which are critically influenced by the annealing temperature and crystallite size of the nanomaterials.     

Isomeric ent‐Labdane‐Type Diterpenoids from the Stems of Rhizophora mucronata

Two new constitutional isomers of ent‐labdane‐type diterpenoids, 1 and 2 , with an unusual seven‐membered lactone moiety (i.e., 1 ), together with two known compounds, 3 and 4 , were isolated from the acetone extract of Rhizophora mucronata. Their structures were elucidated as rhizomucronol A and B ( 1 and 2 , resp.) by spectroscopic analyses and chemical evidence. The absolute configuration of 2 was established by applying the Mosher ester procedure.     

Solvent extraction studies on the complexation of palladium with alpha benzoin oxime

Summary For the recovery of palladium from high level liquid waste (HLLW) a rapid and selective method of separation of palladium have been developed using alpha benzoin oxime (ABO) in Solvesso 100 in our laboratory. In continuation of this work, a detailed study is presented to determine the empirical formula (composition) of the palladium-alpha benzoin oxime (Pd-ABO) complex formed during solvent extraction with ABO in Solvesso 100. Both, the molar ratio method and the isomolar series method extended to two phase system are followed to establish the empirical formula of the Pd-ABO complex. The ligand to metal ratio is computed by analyzing the palladium concentration in the organic phase by direct spectrometry, by analysis of the aqueous phase using Arsenazo-III and also by using the ¹⁰⁹Pd tracer technique. Degree of dissociation and apparent instability constant of the Pd-ABO complex are reported.     

The Weierstrass Transform for a Class of Generalized Functions

The classical theory of the Weierstrass transform is extended to a generalized function space which is the dual of a testing function space consisting of purely entire functions with certain growth conditions developed by Kenneth B. Howell. An inversion formula and characterizations for this transform are obtained. A comparative study with the existing literature is also undertaken.     

Influence of Co(III) Polypyridyl Complexes on Luminescence Behavior,DNA Binding,Photocleavage, Antimicrobial Activity and Molecular Docking Studies

A new ligand FIPB?=?5-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)furan-2-yl-2-boronic acid, having three cobalt(III) polypyridyl complexes [Co(phen)₂(FIPB)]³⁺(1) {FIPB?=?5-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)furan-2-yl-2-boronic acid}, (phen?=?1,10-Phenanthroline), [Co(bpy)₂(FIPB)]³⁺(2) (bpy?=?2,2’bipyridyl), [Co(dmb)₂(FIPB)]³⁺(3) (dmb?=?4, 4′-dimethyl 2, 2′-bipyridine) have been synthesized and characterized by elemental analysis, ES-MS,¹H-NMR, ¹³C-NMR, UV-Vis and FTIR. Their DNA binding behavior has been explored by various spectroscopic titrations and viscosity measurements, which indicated that all the complexes bind to calf thymus DNA by means of intercalation with different binding strengths. The binding properties of these all three complexes towards calf-thymus DNA (CT-DNA) have been investigated by UV-visible, emission spectroscopy and viscosity measurements.The experimental results suggested that three Co(III) complexes can intercalate into DNA base pairs,but with different binding affinities. Photo induced DNA cleavage studies have been performed and results indicate that three complexes efficiently cleave the pBR322-DNA in different forms. The three synthesized compounds were tested for antimicrobial activity by using Staphylococcus aureus and Bacillus subtilis organisms, these results indicated that complex 1 was more activity compared to other two complexes against both tested microbial strains. The in vitro cytotoxicity of these complexes was evaluatedby MTT assay, and complex 1 shows higher cytotoxicity than complex 2 and 3 on HeLa cells.