Crystal to Crystal Guest Exchange in a Mixed Ligand Metal-Organic

ABSTRACT: The occluded solvent in a mixed ligand metal-organic framework has been displaced by n-hexanol, chloroform, and nitrobenzene in a crystal to crystal guest exchange. TheX-ray structures of the three new solvent adducts of Zn2NDC2DPNI2 reveal the complete replacement of N0,N-dimethylformamide with the new guest. Structural changes to the framework geometry in response to the size of the incoming guest are also exhibited. These new frameworks are characterized by powder X-ray diffraction, thermal gravimetric analysis coupled with infrared spectroscopy, and cross-polarization magic angle spinning NMR. Introduction. Metal-organic frameworks (MOFs) are an emerging class of porous materials with extremely high surface area.1 These highly designable organic-inorganic hybrids are capable of a variety of applications, such as chemical separa-tions,2 catalysis,3 fuel storage,4 and small molecule preconcentra