Vacuum-Induced Guest N,N′-Diethylformamide Binding in a Metastable Cd5-Based Metal- Organic Framework
Yan Li1, Zhi-Min Hao1, Meng-Yao Chao1*（晁梦瑶）, Wen-Hua Zhang1*（张文华）, and David J. Young2
1 College of Chemistry, Chemical Engineering and Materials Science, Soochow University,Suzhou 215123, China
2 College of Engineering, Information Technology and Environment, Charles Darwin University,Darwin, Northern Territory 0909, Australia
Inorg. Chem.2022, 61, 50, 20227--20231
A three-dimensional (3D) metal–organic framework (MOF) of [Et2NH2]2[Cd5(BTB)4(DEF)2]·4.75DEF (1; H3BTB = benzene-1,3,5-tribenzoic acid and DEF = N,N′-diethylformamide) sustained by symmetrical Z-shaped Cd5 secondary building units (SBUs) with an intrinsically metastable host framework has been prepared and characterized. Upon gentle vacuum (800 Pa) at 50 °C, some encapsulated DEF solvates are released, leading to pore-shape changes and Cd2+ coordination geometry distortion. This is followed by DEF solvate migration to only one end of the SBU with concomitant symmetry breaking. Additional time under vacuum promoted further structural distortion and topology changes as authenticated by single-crystal X-ray diffraction studies. This work was initially inspired by unusual gas adsorption isotherms and points to the potentially complicated, nonspectator role of coordinative solvents such as DEF during MOF activation.