An Unusual 3D Zinc-Organic Framework Constructed from Paddle-Wheel-Based Carboxylate Sheets Bridged by Acetate Ions

Abstract

A zinc-2,6-naphthalenedicarboxylate metal-organic framework,(H2NEt2)[Zn2(AcO)(NDC)2]·nDEF (1) (DEF = N,N-diethylformamide, AcO = acetate), was solvothermally synthesized in the presence of small amounts of acetic acid and characterized by singlecrystal and powder X-ray diffraction and thermogravimetric analysis. Compound 1 is an anionic 3D paddle-wheel MOF, in which the zincnaphthalenedicarboxylate sheets are linked together by bridging acetate ions. Compound 1 exhibits large square channels (13 x 13 Å), which contain DEF molecules and, alternatively, charge-balancing diethylammonium cations in situ generated by the hydrolysis of DEF under the solvothermal conditions used. The anionic host framework of 1 is unstable upon removal of guest DEF molecules suggesting that host-guest hydrogen bond interactions are crucial for maintaining the structural integrity of this compound.