Charge-Assisted Soft Supramolecular Porous Frameworks: Effect of External Stimuli on Structural Transformation and Adsorption Properties

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• 作者：Arpan Hazra ; K. L. Gurunatha ; Tapas Kumar Maji
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：November 6, 2013
• 年：2013
• 卷：13
• 期：11
• 页码：4824-4836
• 全文大小：1125K
• 年卷期：v.13,no.11(November 6, 2013)
• ISSN：1528-7505

文摘

Four novel supramolecular frameworks {(H₂鈥揵pee)₄[Fe(CN)₆]₂路9H₂O} (1), {(H₂鈥揵pee)(H₃O)₂[Fe(CN)₆]路2H₂O} (2), {[(H₂-bpee)(H-bpee)]₂[Fe(CN)₆]₂路5H₂O} (3), and {[(H_1.5鈥揵pee)₂][Fe(CN)₆]路6H₂O}, (4) [bpee = 1,2-bis(4鈥損yridyl)ethylene] have been synthesized by the reaction of bpee and K₄[Fe(CN)₆] (for 1 and 2) or K₃[Fe(CN)₆] (for 3 and 4) in aqueous medium. The supramolecular structures are constructed by cooperative noncovalent hydrogen bonding and 蟺路路路蟺 interactions between protonated bpee, [Fe(CN)₆]^{3/4鈥?/sup>, and crystalline water molecules. All the supramolecular soft hosts transformed to two different states depending upon the dehydration condition, as observed from the PXRD patterns. When the compounds were activated under vacuum at 373 K (1鈥测€?b>4鈥?, they exhibit different adsorption behavior with different adsorbates like H₂O, MeOH, and EtOH compared to when they were activated under high vacuum at room temperature for 24 h (1鈥斥€?b>4鈥?. Desolvated compounds 1鈥测€?b>4鈥?show gradual uptake of water, while multistep water adsorption profiles were observed with 1鈥斥€?b>4鈥? suggesting a difference in hydrophilicity in these two sets of compounds. Further, 1鈥测€?b>4鈥?and 1鈥斥€?b>4鈥?unveil type I and double step MeOH (at 293 K) adsorption profiles, respectively, which have been correlated to guest-induced structural transformation in the desolvated soft frameworks obtained at two different activation conditions.}