title: Crystallochemical formula as a tool for describing metal-ligand complexes - a pyridine-2,6-dicarboxylate example.
abstract: Compounds (299) containing 494 symmetrically independent pyridine-2,6-dicarboxylate moieties have been investigated. Among them the structures of Na(3)[Nd(Pydc)(3)].14H(2)O and Na(3)[Er(Pydc)(3)].11.5H(2)O, where H(2)Pydc is pyridine-2,6-dicarboxylic acid, were determined by single-crystal X-ray diffraction, while the others were taken from the Cambridge Structural Database. The characteristics of any complex by means of the ;method of crystallochemical analysis' are described, and the coordination types of all the Pydc ions and crystallochemical formulae of all the compounds were determined. Although the ion can act as a mono-, bi-, tri-, tetra- and pentadentate ligand, 96% of Pydc ions are coordinated to the central A atom in the tridentate-chelating mode. The dependence of the denticity and geometry of pyridine-2,6-dicarboxylate, as well as of the composition of Pydc-containing complexes, was studied as a function of the nature of the A atom, the molar ratio Pydc:A and the presence of neutral or acidic ligands in the reaction mixture.
authors.affiliation: Samara State University, Ac. Pavlov St. 1, Samara 443011, Russian Federation.
authors.forename: Viktor N
authors.initials: VN
authors.lastname: Serezhkin
authors.forename: Anna V
authors.initials: AV
authors.lastname: Vologzhanina
authors.forename: Larisa B
authors.initials: LB
authors.lastname: Serezhkina
authors.forename: Ekaterina S
authors.initials: ES
authors.lastname: Smirnova
authors.forename: Elena V
authors.initials: EV
authors.lastname: Grachova
authors.forename: Polina V
authors.initials: PV
authors.lastname: Ostrova
authors.forename: Mikhail Yu
authors.initials: MY
authors.lastname: Antipin
mesh_terms: D018360:Crystallography, X-Ray; D016208:Databases, Factual; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010848:Picolinic Acids / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D008024:Ligands; D008670:Metals; D009942:Organometallic Compounds; D010848:Picolinic Acids; C004860:dipicolinic acid