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Crystallography of Representative Flexible MOFs Based on Pillard Cyanonickelate (PICNIC) Architecture



Winnie K. Wong-Ng, Jeffrey T. Culp, Yu-Sheng Chen, Christopher Matranga


In recent years, a number of novel compounds known as flexible pillared layer porous coordination polymer (or flexible metal organic framework (MOFs)) have been discovered which show reversible structural transitions between low porosity and high porosity phases during the adsorption and desorption of guests. Materials based on the pillared cyano-bridged architecture, [Ni’(L)Ni(CN)4]n (L = pillar organic ligands), or known as PICNICs, have been shown to be especially diverse. For example, their structure can be rigid or dynamic depending on the choice of pillar organic ligands. This article gives a brief summary of the crystallography of flexible MOFs with highlights on PICNICs. Our recent work on structure characterization of three Ni(CN)4-based compounds (Bpene, Ni-BpyMe and Ni-BpyNH2), and the CO2 sorption properties of two selected compounds is described. As crystal growth is often controlled by solvent of crystallization, our paper also describes the structures of two Ni(CN)4-based crystals where, instead of forming 3-D architect, 2-D (layer, L=bpy) and 1-D (chain, L=naph) lattices were established due to the presence of the –NH3 groups (from solvent of crystallization) in the structure.


MOFs, Flexible Ni(CN)4-based metal-organic frameworks, crystallography, structure and adsorption properties


Wong-Ng, W. , Culp, J. , Chen, Y. and Matranga, C. (2016), Crystallography of Representative Flexible MOFs Based on Pillard Cyanonickelate (PICNIC) Architecture, Crystals, [online], (Accessed May 29, 2024)


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Created September 5, 2016, Updated February 24, 2020