title: Two novel Cu(II) diphosphonates: structural, spectral and magnetic studies.
abstract: By introducing the second organic N-heterocyclic ligands 2,2'-bipyridine (2,2'-bipy)/1,10-phenanthroline (phen), two mono-/bi-nuclear examples of Cu(II)-diphosphonate coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), [Cu(H4L)2(2,2'-bipy)]·H2O 1 and [Cu(H3L)(phen)]2·(HOCH2CH2OH)0.52, have been solvothermally obtained and characterized by powder X-ray diffraction, elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that both the two compounds possess zero-dimensional structures, built from mononuclear unit [CuO4N2]n for 1 and binuclear unit [-Cu-O-P-O-]2n with a double O-P-O bridge for 2 in syn-anti fashion. Then H-bond or/and π-π interactions further expand the two zero-dimensional structures into the three-dimensional supramolecular frameworks. Fluorescent measurements reveal that the maximum emission peaks of 1-2 centered at 433.5nm for 1 and 434.5nm for 2, respectively, are mainly caused by intraligand π(*)-π emission state of N-heterocyclic ligands (λex=235nm). The further magnetic study shows the two coordination polymers exhibit antiferromagnetic behavior for 1 between the mononuclear units, while ferromagnetic behavior for 2 derived from double O-P-O bridges in syn-anti mode between the metal centers.
authors.affiliation: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China. kuirongma@163.com
authors.forename: Kui-Rong
authors.initials: KR
authors.lastname: Ma
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yu-He
authors.initials: YH
authors.lastname: Kan
authors.forename: Hua-You
authors.initials: HY
authors.lastname: Hu
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Cong
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Zhang
mesh_terms: D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004164:Diphosphonates / Q000737:chemistry*; D006860:Hydrogen Bonding; D008024:Ligands; D060328:Magnetic Phenomena; D008968:Molecular Conformation; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D004164:Diphosphonates; D008024:Ligands; D003300:Copper
keywords: Crystal structure; Cu(II)-diphosphonate; Magnetism; Spectroscopy