Solvent effects on the structures and magnetic properties of two doubly interpenetrated metal-organic frameworks

3D Metal-Organic Frameworks Based on Co(II) and Bithiophendicarboxylate: Synthesis, Crystal Structures, Gas Adsorption, and Magnetic Properties

Three new 3D metal-organic porous frameworks based on Co(II) and 2,2′-bithiophen-5,5′-dicarboxylate (btdc²⁻) [Co₃(btdc)₃(bpy)₂]·4DMF, 1; [Co₃(btdc)₃(pz)(dmf)₂]·4DMF·1.5H₂O, 2; [Co₃(btdc)₃(dmf)₄]∙2DMF∙2H₂O, 3 (bpy = 2,2′-bipyridyl, pz = pyrazine, dmf = N,N-dimethylformamide) were synthesized and structurally characterized. All compounds share the same trinuclear carboxylate building units {Co₃(RCOO)₆}, connected either by btdc^2– ligands (1, 3) or by both btdc^2– and pz bridging ligands (2). The permanent porosity of 1 was confirmed by N₂, O₂, CO, CO₂, CH₄ adsorption measurements at various temperatures (77 K, 273 K, 298 K), resulted in BET surface area 667 m²⋅g⁻¹ and promising gas separation performance with selectivity factors up to 35.7 for CO₂/N₂, 45.4 for CO₂/O₂, 20.8 for CO₂/CO, and 4.8 for CO₂/CH₄. The molar magnetic susceptibilities χ_p(T) were measured for 1 and 2 in the temperature range 1.77–330 K at magnetic fields up to 10 kOe. The room-temperature values of the effective magnetic moments for compounds 1 and 2 are μ_eff (300 K) ≈ 4.93 μ_B. The obtained results confirm the mainly paramagnetic nature of both compounds with some antiferromagnetic interactions at low-temperatures T < 20 K in 2 between the Co(II) cations separated by short pz linkers. Similar conclusions were also derived from the field-depending magnetization data of 1 and 2.

Four CuI(ett) coordination polymorphs and changes in XRD upon hydrothermal condition optimization

Four [Cu^I(ett)]_n coordination polymorphs (1-α, 1-β, 1-γ and 1-δ), based on 5-(ethylthio)-1H-tetrazole (Hett), have been prepared successfully.

A Novel, Interpenetrating Metal–Organic Framework: Synthesis, Structure, and Luminescence Detection of Nitrobenzene

A 3D heterometal–organic framework {[TbZn(BPDC)2(HCOO)(H2O)3]·2H2O}n (1) was constructed from Tb3+ and Zn2+ as metal ions and 4,4′-dicarboxylate-2,2′-dipyridine (H2BPDC) as the ligand using a solvothermal method. Single-crystal X-ray diffraction analysis revealed that compound 1 is 2-fold interpenetrating. Thermogravimetric and solvent stability analyses demonstrated that compound 1 displayed good thermal and solvent stabilities. The luminescent explorations revealed that compound 1 exhibited highly sensitive and qualitative detection of nitrobenzene at the ppm level. To our knowledge, the present study reports for the first time the use of an interpenetrating heterometallic metal–organic framework as a luminescent probe for nitrobenzene.

Multifunctional lanthanide–organic frameworks for fluorescent sensing, gas separation and catalysis

Two lanthanide MOFs have been synthesized based on a novel anthracene-functionality semi-rigid ligand, which show good selective fluorescent sensing capabilities for 4-nitrophenol and Al³⁺.

HCl chemisorption-induced drastic magneto-structural transformation in a layered cobalt–phosphonotriazolate coordination polymer

A stimuli-responsive magnetic coordination polymer was synthesized, which shows an antiferro- to ferromagnetic response to HCl vapour in a crystal-to-crystal transformation.

Correlation between structural, physical and chemical properties of three new tetranuclear NiII clusters

The structural alteration in investigated tetranuclear Ni^II clusters induced only by solvent exchange resulted in significant changes in their physical and chemical properties.