Rational Design and Control of the Dimensions of Channels in a Series of 3D Pillared Metal−Organic Frameworks: Synthesis, Structures, Adsorption, and Luminescence Properties

A systematic variation of diamine ligands, TED, Bipy, and Bpe [TED = triethylenediamine, Bipy = 4,4′-bipyridine, and Bpe = trans- bis(4-pyridyl)ethylene], pillaring 2-fold (6,3) layers constructed from metallic trinuclear SBUs and flexible CTC ligands gives rise to a series of porous metal−organic frameworks, Cd 3 (CTC) 2 (TED)(H 2 O) 2 ·(H 3 O) 2 Cl 2 ( 1 ), Cd 3 (CTC) 2 (Bipy)(DMF) 2 ·(DMF)(H 2 O) 2 ( 2 ), Cd 3 (CTC) 2 (Bpe)(DMF) 2 ·(DMF)(H 2 O) 2 ( 3 ), Zn 3 (CTC) 2 (Bipy)·(DMF)(H 2 O) 2 ( 4 ), and Zn 3 (CTC) 2 (Bpe)·(DMF)(H 2 O) 2 ( 5 ) (compounds 1–5 named JUC-34, JUC-44, JUC-45, JUC-46, JUC-47, respectively, JUC-Jilin University, China, CTC = cis,cis- 1,3,5-cyclohexanetricarboxylate and DMF = N,N ′-dimethylformamide). These open frameworks have been synthesized under mild conditions possessing three-dimensional connectivity with interconnecting pores and the same (4 3 ) 2 (4 6 ·6 18 ·8 4 ) topology. The water adsorption isotherms of these compounds show type Ι behavior with approximately 0.07, 0.10, 0.12, 0.17, and 0.19 mL/g pore volumes, respectively. Photoluminescence investigations reveal that they display strong emission in the blue/green regions.