Sharif Digital Repository

The complexation between folic acid and the complexes of Cu(L)2 (L = Glycine, Alanine, Valine) were investigated using UV.Vis spectroscopy. The values of the equilibrium constant K and molar absorption coefficient Ɛ of the complexes were estimated in the aquation environment at various temperatures. The temperature dependence of the K can be used for the determination of the thermodynamic reaction quantities (∆G, ∆H, ∆S) for linear regression fits to the Van’t Hoff equation. The kinetic studies reveals that the stoichiometry of reaction were 1:1 for these systems. All reaction were endothermic and the values of the ∆H are positive. In all cases entropy increased and the values of the ∆S... 

Folic acid is a pterin derivative containing a glutamyl moiety and essential for biological reactions. Pterins are a class of heterocyclic compounds with unique structures and biological functions. Tetrahydrobiopterine has been known to be essential for catalytic hydroxylation of aromatic amino acids by metal ions-containing aromatic amino acid hydroxylases. Metal ions at the active site of these enzymes have been inferred to be closely associated with the pterin cofactors in the catalytic reactions.Information on pterin-metal interaction may give clues to the role of metal ions in enzymatic reactions. With these points in mind, studies have been conducted to verify the formation of ternary... 

In this research, a new group of N2O2–azacrown macrocyclic ligands with different macroring size from 15 to 18 was synthesized using one-pot facile and high yield reaction. The products were characterized applying FT-IR, 1H and 13C NMR spectroscopies as well as elemental analysis. The single crystal structure of 18-membered macrocyclic ligand was also determined by x-ray crystallography. The crystallographic data showed such strong inter-molecular hydrogen bonding which excluded their nitrogen-donor groups, and initial investigation with UV-Vis spectroscopy shows no intraction with [60]fullerene, despite of presence of these interacrtions in their parent macrocycles. The result of Job’s... 

By considering previous experiments undertaken in our laboratory on O2Nx (x=2,3) azacrown complexes with [60]fullerene, it was found that factors such as the macroring size, type and number of the donors groups in these macrocyclic ligands had significant effects on their selectivity towards [60]fullerene complexation. In this research, three N2O2N–azacrown macrocyclic ligand having uniform distribution of nitrogen atoms in macroring was synthesized using direct synthesis and high dilution method. The products were characterized applying 1H and 13C NMR spectroscopy as well as elemental analysis. Interaction of these ligands with [60]fullerene and Cu(II) were monitored by UV-vis spectroscopy... 

A set of azacrown macrocyclic ligands bearing pyridine moiety (bp, 1p, 2p) were synthesized and characterized by single-crystal X-ray diffraction (SCXRD), elemental analysis, FT-IR, 1H and 13C NMR methods. The complexes of zinc tetraphenylporphyrin (ZnTPP) with the bp and 1p as the axial ligand were synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, IR, 1H and 13C NMR, fluorescence, UV-vis, cyclic voltammetry, together with TD DFT calculations. By employing this method for ZnTPPbenz and ZnTPPH complexes elucidated that the pyridine moiety was bonded through the fifth- coordination site on the zinc metal atom. In the following study, the coordination... 

In the present study, the coordination chemistry of an O4N4-tetrabenza-crown ether macrocyclic ligand L1 with M2+ (M= Cu, Cd, Hg, and Pb) was investigated by employing UV-visible, 1H-NMR spectroscopy in their solutions. According to the association constants calculated by 1H-NMR titrations, the complex formation stability for these closed shell cations was found in a series of Pb > Hg > Cd, leading to the larger cation, the better accommodation with L1. Moreover, the supramolecular interaction of L1 with fullerene C60 was also assessed by UV-visible spectroscopy. Meanwhile, the structure of [Cd(1)]2+ complex was determine by X-ray crystallographic method in their solid state. A square...