A series of novel 3D 3d-4f heterometallic cluster-based coordination polymers, [Ln4Cr4(μ3-O)4(μ4-O)4(NA)8(H2O)12]·xH2O (Ln = 1-Gd, 2-Tb, 3-Er; HNA = nicotinic acid; x = 13 (1-Gd), 11.33 (2-Tb), 15 (3-Er)), have been successfully synthesized by hydrothermal method using nicotinic acid as bridging ligand. The single-crystal X-ray diffraction (SCXRD) analysis indicated that the basic unit of Ln4Cr4 shows a butterfly-shaped structure. Furthermore, each Ln4Cr4 cluster connects with other four Ln4Cr4 clusters by bridging NA– ligands to form a 3D structure containing interesting 1D honeycomb-shaped coordination nanotubes. The variable temperature magnetic susceptibility measurements of compound 1 revealed that the existence of antiferromagnetic (AF) coupling between the metal ions in the Gd4Cr4 clusters. Field-dependent isothermal magnetization studies displayed that the magnetic entropy change (−ΔS m) value of 1-Gd reached 22.05 J K–1 kg–1.

Ammonia is one of hazardous pollutants that can endanger human life. It must be controlled with sorbent material that can target ammonia with high selectivity. Hollow mesoporous silica spheres (HMSS) are conventionally used as a carrier of catalyst. But ammonia can be absorbed selectively via impregnation of metal halide, such as MgCl2. In this work, the porous matrix HMSS is synthesized via one step preparation, and the absorption sites are adopted by impregnation method. The influence of loading content is taking into consideration on absorption performance. The structure of prepared material is analysed using FTIR, XRD, BET, TEM tools. The absorption capacity is performed in a fixed bed column and characterized by dynamic breakthrough. The results show that the composite material MgCl2/HMSS can absorb 20 mol/kg ammonia at 30 °C and 0.8 atm which is competitive than commercial sorbents. Meanwhile, 80 wt% of loading content is reported the highest ammonia capacity for the same type of sorbent. The experimental data can be reproducible for many times.