Syntheses, Structures, and Magnetic Properties of Two Series of 3d–4f Heterometallic Coordination Polymers Derived from Pyrazine‐2,3‐dicarboxylic Acid

Novel Lanthanide (III) Complexes Derived from an Imidazole-Biphenyl-Carboxylate Ligand: Synthesis, Structure and Luminescence Properties

A series of neutral mononuclear lanthanide complexes [Ln(HL)₂(NO₃)₃] (Ln = La, Ce, Nd, Eu, Gd, Dy, Ho) with rigid bidentate ligand, HL (4'-(1H-imidazol-1-yl)biphenyl-4-carboxylic acid) were synthesized under solvothermal conditions. The coordination compounds have been characterized by infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. According to X-ray diffraction, all the complexes are a series of isostructural compounds crystallized in the P2/n monoclinic space group. Additionally, solid-state luminescence measurements of all complexes show that [Eu(HL)₂(NO₃)₃] complex displays the characteristic emission peaks of Eu(III) ion at 593, 597, 615, and 651 nm.

Syntheses, Structures, and Magnetic Properties of a Series of Heterotri-, Tetra- and Pentanuclear LnIII⁻CoII Compounds

Three types of Ln(III)⁻Co(II) heterometallic compounds, LnCo₂(L1)₇(bipy)₂ (Ln = Pr-1, Eu-2, Sm-3, Gd-4, Tb-5, Dy-6) (L1 = 4-chlorobenzoate, bipy = 2,2'-bipyridine), Ln₂Co₂(L₂)10(bipy)₂ (Ln = Sm-7, Gd-8, Tb-9, Dy-10, Ho-11, Er-12, Yb-13), (L2 = 2,4-dichlorobenzoate, bipy = 2,2'-bipyridine, phen = 1,10-phenanthroline), and Ln₂Co₃(L1)12(bipy)₂ (Ln = Ho-14, Er-15, Yb-16), were synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction, IR spectroscopy and magnetic measurements. Structural analyses revealed that 14⁻16 take on a unique linear pentanuclear structural motif. Interestingly, the Ho-containing compound 14 exhibits magnetic relaxation behavior.

Pyrazine dicarboxylate-bridged arsenotungstate: synthesis, characterization, and catalytic activities in epoxidation of olefins and oxidation of alcohols

The catalytic properties and polyanionic structure of pyrazine dicarboxylate-bridged arsenotungstate are reported.

A series of 3D lanthanide coordination polymers decorated with a rigid 3,5-pyridinedicarboxylic acid linker: syntheses, structural diversity, DFT study, Hirshfeld surface analysis, luminescence and magnetic properties

Single crystal X-ray diffraction studies reveal the formation of six new coordination polymers (CPs) with the general formulas [Dy(3,5-pdc)(3,5-pdcH)(H2O)2]n·nH2O (1), [Pr2(3,5-pdc)3(H2O)2]n·2n(H2O) (2), [Sm2(3,5-pdc)3(H2O)3]n·nH2O (3), {[Eu2(3,5-pdc)3(H2O)3(CH3CHO)]n·n[2(H2O)(DMF)]} (4), {[Gd2(3,5-pdc)3 (H2O)2]n·2nH2O} (5) and [Er(3,5-pdc)(adip)0.5(H2O)]n (6) (where 3,5-pdc2- = fully deprotonated; 3,5-pdcH- = partially deprotonated 3,5-pyridinedicarboxylic acid; adip2- = fully deprotonated adipic acid; and DMF = dimethylformamide) by solvothermal self-assembly of lanthanide ions with rigid 3,5-pyridinedicarboxylic acid as a linker and adipic acid as an auxiliary flexible spacer (only coordinated in CP 6). CPs 1 and 2 crystallize in the triclinic P1[combining macron] space group, whereas CPs 3, 4 and 6 crystallize in the monoclinic P21/n, P21/c and C2/c space groups, respectively. CP 5 exhibits the trigonal R3 space group. The 3,5-pdc ligand exhibits eight diverse coordination modes in CPs 1-6, whereas the adipic acid spacer in CP 6 shows only one coordination mode (μ4-κO:κO,O:κO:κO,O). The organic ligands interconnect with metal ions to generate 3D metal-organic frameworks with a variety of intriguing topologies. Theoretical studies, DFT calculations and Hirshfeld surface analysis support the structures adopted by the various CPs. CPs 3 (Sm) and 4 (Eu) emit strong ligand-sensitized characteristic f-f luminescence. Weak ferromagnetic interactions have been studied at low temperatures for CP 1 and CP 5.