Three fluorescent asymmetric bis-urea receptors (L1-L3) have been synthesised. The binding properties of L1-L3 towards different anions (fluoride, acetate, hydrogencarbonate, dihydrogen phosphate, and hydrogen pyrophosphate HPpi3-) have been studied by means of 1H-NMR, UVVis and fluorescence spectroscopies, single crystal X-ray diffraction, and theoretical calculations. In particular, a remarka...

the structure and properties of niobapyrimidinium complex were examined by density functionaltheory method (mpw1pw91). the effect of solvent on the structural parameters, frontier orbitalenergies and hyperpolarizability (
tot) of this molecule has been explored. the thermodynamicproperties of the title compound at different temperatures have been calculated. also, the parasubstitutionseffect on...

We present a new relativistic formulation for the calculation of nuclear magnetic resonance ~NMR! shielding tensors. The formulation makes use of gauge-including atomic orbitals and is based on density functional theory. The relativistic effects are included by making use of the zeroth-order regular approximation. This formulation has been implemented and the Hg NMR shifts of HgMe2 , HgMeCN, Hg...

A series of lanthanide complexes have been synthesized from 1,4,7,10-tetrakis(2-pyridylmethyl)-1,4,7,10-tetraazacyclododecane. Crystallographic studies indicate that, in the solid phase, all of the lanthanide ions are 9-coordinate and are bound to eight N atoms from the donor ligand, with the ninth site being filled by a counterion or solvent molecule. In solution, time-resolved luminescence st...

The importance of intramolecular hydrogen bonding between the carboxylate oxygen and amide proton of succinamate anion has been investigated by quantum mechanical simulations as a function of solvent for comparison with conformational equilibria estimated by NMR spectroscopy. The focus is on those methodological considerations of general interest to the conformational equilibrium problem, which...

Higher-affinity RNA aptamers to GTP are more informationally complex than lower-affinity aptamers. Analog binding studies have shown that the additional information needed to improve affinity does not specify more interactions with the ligand. In light of those observations, we would like to understand the structural characteristics that enable complex aptamers to bind their ligands with higher...

In this research, the nanoorganic reagent 4 (4-sulphophenylazo) pyrogallol was prepared by method of forming diazonium salt in an acidic medium coupling compound sulfadiazine with pyrogallol. The complex iron (III) also prepared. and were diagnosed through electronic spectrometers, UV-Visible Spectrophotometers, IR, X-ray diffraction measurements, XRD, 1H-NMR-C13-NMR measurements. effect solven...

the interaction between the solute and the solsent molecules play a crucial role in understanding the various molecular processes involved in chemistry and biochemistry, so in this work the potential energy of active site of azurin have been calculated in solvent by the monte carlo simulation. in this paper we present quantitative results of monte carlo calculations of potential energies of ...

Refinement of NMR structures by molecular dynamics (MD) simulations with a solvent model has improved the structural quality. In this study, we applied MD refinement with the generalized Born (GB) implicit solvent model to protein structure determined under membrane-like environments. Despite popularity of the GB model, its applications to the refinement of NMR structures of hydrophobic protein...