Developing a magnetic metal organic framework of copper bearing a mixed azido/butane-1,4-dicarboxylate bridge: magnetic and gas adsorption properties

A magnetic metal organic framework {[Cu(but-1,4-dc)0.5(N3)(H2O)]·H2O}n (MFUM-1(Cu)) (but-1,4-dc = butane-1,4-dicarboxylate) was synthesized and characterized structurally and magnetically. In MFUM-1(Cu), each CuII ion has a distorted octahedral geometry with an obvious Jahn-Teller distortion, where the coordination environment is composed of mixed EO-azido/aliphatic based carboxylate/H2O threefold bridges. These bridges extend the structure of MFUM-1(Cu) in two dimensions by covalent connectivity and form square-shaped channels. Also, a study was done to determine the effectiveness of sonochemical synthesis for the preparation of nano-sheets of MFUM-1(Cu) and subsequently the influence of particle size on physical properties such as magnetic behavior and thermal stability. The particles were characterized by elemental analyses, infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD) analyses. The effects of parameters such as concentration, solvent, and reaction time on the size distribution, morphology, and yield of product were carefully studied. The magnetic properties of MFUM-1(Cu) and corresponding nano-structure were examined which indicated metamagnetism with strong intrachain ferromagnetic coupling versus the weak interchain antiferromagnetic coupling. Finally, the application of MFUM-1(Cu) in the separation of carbon dioxide from nitrogen and also from methane was theoretically investigated. High calculated selectivity of CO2 over N2 and CH4 reveals the potential application of MFUM-1(Cu) in practical systems of gas separation.

Synthesis, structure, and magnetic properties of new layered phosphate halides Sr2Cu5(PO4)4X2·8H2O (X = Cl, Br) with a crown-like building unit

Two new compounds Sr₂Cu₅(PO₄)₄X₂·8H₂O (X = Cl and Br) are synthesized by a conventional hydrothermal method. Sr₂Cu₅(PO₄)₄Cl₂·8H₂O crystallizes in the tetragonal system with a space group of P42₁2, while Sr₂Cu₅(PO₄)₄Br₂·8H₂O crystallizes in the space group P4/nmm, which are found to have a similar framework of layered structure, in which the crown-like {Cu₅(PO₄)₄X₂} building units connect to each other forming a 2D corrugated sheet with vacancies, while the Sr²⁺ cations are located along the vacancies. The spin lattice of two compounds built by Cu²⁺ ions shows a new type of corrugated square. Magnetic measurements confirmed that both Sr₂Cu₅(PO₄)₄X₂·8H₂O (X = Cl and Br) exhibit antiferromagnetic ordering at low temperatures. A fit of theoretical model shows exchange interaction J = -25.62 K for the Cl-analogue and J/k_B = -26.47 K for the Br-analogue.

Ligand directed structural diversity and magnetism in copper(ii)–azido assemblies with isomeric aminopyridines: synthesis, structure, magnetism and theoretical studies

Ligand geometry and molar ratios play an influential role in directing the supramolecular assemblage and associated magnetic properties as described for the Cu(ii) complexes involving isomeric aminopyridines and azide.

A unusual two-dimensional azido-Cu(ii) network with benzoate derivative as a co-ligand exhibiting ferromagnetic order and slow magnetic relaxation

A 2D layer-like Cu(ii) compound with multiple-bridges of azido, carboxylate and hydroxyl ligands, featuring strong ferromagnetic coupling and slow magnetic relaxation.