title: Structural, spectral and magnetic studies of two Co(II)-N-heterocyclic diphosphonates based on multinuclear units.
abstract: Two examples of Co(II)-N-heterocyclic coordination polymers based on 1-hydroxyethylidenediphosphonic acid (H5L=CH3C(OH)(PO3H2)2), namely 0.5(H3NCH2CH2NH3)·[Co6(Cl2)(H3L)2(H2L)(HL)(2,2'-bipy)6] 1 and 2(NH4)·[Co3(HL)2(H2O)2(phen)2]·2(H2O) 2, have been solvothermally obtained by introducing the second ligands 2,2'-bipyridine/1,10-phenanthroline (2,2'-bipy/phen) and characterized by powder X-ray diffraction (PXRD), elemental analysis, IR, TG-DSC. The single-crystal X-ray diffractions show that compound 1 possesses a 0-D structure with hexa-nuclear cluster [Co6(O-P-O)8] built through single/double O-P-O bridges and compound 2 displays a 1-D ladder-like chain structure with magnetic topology building blocks [Co4(O-P-O)4]n. Then H-bonding and π-π stacking interactions further expand the two low-dimensional structures into three-dimensional supramolecular frameworks. Fluorescent measurements reveal that both the maximum emission peaks of 1-2 are centered at 423nm, mainly deriving from intraligand π*-π transition state of N-heterocyclic ligand 2,2'-bipy/phen, respectively. Magnetism data indicate that 1 exhibits antiferromagnetic behavior within hexa-nuclear Co(II) clusters, while 2 shows weak ferromagnetic interactions in 1-D topology Co(II)-chain, showing promising potential as magnetic materials.
authors: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China.
authors: Chen
authors: C
authors: Zhao
authors: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China. Electronic address: kuirongma@163.com.
authors: Kui-Rong
authors: KR
authors: Ma
authors: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China.
authors: Yu
authors: Y
authors: Zhang
authors: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China.
authors: Yu-He
authors: YH
authors: Kan
authors: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China.
authors: Rong-Qing
authors: RQ
authors: Li
authors: Jiangsu Key Laboratory for Chemistry of Low-dimensional Materials, School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huaian 223300, PR China.
authors: Hua-You
authors: HY
authors: Hu
keywords: Co(II) diphosphonate; Fluorescence; Magnetism; Structure