Synthesis, characterization, crystal structures, and solution studies of Ni(II), Cu(II) and Zn(II) complexes obtained from pyridine-2,6-dicarboxylic acid and 2,9-Dimethyl-1,10-Phenanthroline

Abstract

The homonuclear water-soluble and air stable compounds (dmpH) (H 5 O 2 ) [M(pydc) 2 ].0.5H 2 O (M = Ni(II) (1), Cu(II) (2), Zn(II) (3); pydcH 2 = pyridine-2,6-dicarboxylic acid, dipicolinic acid, dmp = 2,9-dimethyl-1,10-phenanthroline) have been prepared by self-assembly synthesis in aqueous solution at room temperature, and characterized by IR, 1 H NMR, 13 C NMR, elemental analysis and X-ray diffraction single crystal analyses for 1, 2 and 3. The complexes 1-3 represent the isostructural features. Extensive hydrogen bonding interactions involving all aqua ligands, dipicolinate oxygens and lattice water molecules further stabilize the complex units by linking them to form three dimensional polymeric networks. The stoichiometry and stability of the all three complexes in aqueous solution were investigated by potentiometric pH titration.

A Rare Example of a Dinuclear Cobalt(II) Complex with Dipicolinate and Bridging 2-Aminopyrazine Ligands. Preparation, Structural, Spectroscopic and Thermal Characterization

“…In the spectrum of 1, the band associated with the antisymmetric stretching mode, ν as (-COO − ), appears at 1638 cm −1 together with ν s (-COO − ) at 1360 cm −1 . The value of ∆[ν as (-COO − ) − ν s (-COO − )] amounts to 278 cm −1 , indicating the presence of carboxylate groups coordinated to metal ions in an unidentate mode [28,29], which is in agreement with the crystal structure. The IR spectrum of 1 shows strong broad bands in the region 3317 -3080 cm −1 , which could be related to the existence of O-H···O hydrogen bonding between water molecules [30].…”

Chromium(III) and Calcium(II) complexes obtained from dipicolinic acid: Synthesis, characterization, X-Ray crystal structure and solution studies

“…The protonation constants of reactants pydcH 2 and dmp and stability constants of the resulting proton transfer adduct and their metal complexes were evaluated using the program BEST described by Martell and Motekaitis [15]. The value of K w = [H + ] [OH -] used in the calculations was according to our previous works [16][17][18][19].…”

“…protonated forms in aqueous solution [16][17][18]. In order to determine the stoichiometry and stability of the Cr 3+ and Ca 2+ complexes with pydc-dmp proton transfer system in aqueous solution, in this work we obtained the equilibrium potentiometric pH titration profiles of pydc, dmp and their 1:1 mixture in the absence and presence of the metal ions (Fig.…”

Supramolecular assembled of hexameric water clusters into a 1D chain containing (H2O)6 and [(H2O)4O2] stabilized by hydrogen bonding in a copper complex

“…It must have been coupled by other indicative peaks such as N-H and O-H stretching frequencies and the stretching frequencies due to the aromatic rings, which originally fall within this region [28-30]. …”