In Situ Generation of NiO Nanoparticles in a Magnetic Metal–Organic Framework Exhibiting Three-Dimensional Magnetic Ordering

NiO nanoparticles were in situ formed in a new metal–organic framework (MOF), [Ni3(pyip)2(HCOO)2(H2O)2] n [1; H2pyip = 5-(pyridine-4-yl)­isophthalic acid], which was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, transmission electron microscopy, and powder and single-crystal X-ray diffraction. The MOF 1 shows a 3,6-connected three-dimensional rtl topology network with a topological symbol of (4.62)2(42.610.83). Magnetic property studies showed that the combination of NiO nanoparticles within the magnetic MOF leads to the occurrence of long-range magnetic ordering below a critical temperature of 18 K.