Syntheses, Structures And Properties Of Trinudear Nickel Clusters-based Microporous Metal-organic Framework

Metal–organic frameworks （MOFs） or porous coordination polymers （PCPs）have attracted intense interests due to their potential applications such as gas storage,separation, catalysis, chemical sensor. Though large numbers of MOFs which may bewith diverse network structures and lots of potential applications have been reported,it is still a challenge that how to construct a MOF purposefully and explore itsproperty. Based on the consideration of metal ion （metal cluster） and many factors,Ni2+is chosen as metal ion, and mix-ligand are used to construct the framework insolvothermal condition. The mix-ligand is BDC and Ina, BDC and na respectively.Trinuclear clusters have been reported as building blocks for MOFs constructiondue to their fixed geometric model and available of coordination sites. Among mostreported cases the metal ions usually bonded to terminal molecules which hamperedthe further connection. With the development of research, terminal molecules areusually replaced by terminal ligand, and it provide a possibility to build the newframework. Here, trinuclear nickel cluster is used as inorganic building block, andtwo compounds are assembled through changing the terminal ligands in solvothermalmethod.Compound Ni₃（OH）（Ina）₃（BDC）_1.5（1） contains two kinds of cages, and has3-Dchannel. The trinuclear cluster is ligated by3BDC and6Ina （three Ina arecarboxylate-connected and the other three Ina are N-connected）, so the9-connecteduninodal node framework is constructed.1is with microporous property, and showsgood adsorption ability toward H2. It has been observed selective sorption C6H6overC6H12through vapour adsorption experiment.Compound Ni₃O（Ni）_0.5（BDC）₂（na）₃is build by three kinds of polyhedra, andcontains3-D channel. The trinuclear cluster is connected by6BDC and2na. The8-connected topology is not built though two of the three terminal molecules havereplaced by na ligand. The6-connected uninodal node topology is constructed instead.The free volume in fully desolvated1is about61%as determined by PLATON.