Halter Dominik P, Klein Ryan A, Boreen Michael A, Trump Benjamin A, Brown Craig M, Long Jeffrey R
Department of Chemistry , University of California , Berkeley , CA 94720 , USA . Email:
Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , CA 94720 , USA.
Chem Sci. 2020 May 27;11(26):6709-6716. doi: 10.1039/d0sc02394a. eCollection 2020 Jul 14.
A new, air-stable, permanently porous uranium(iv) metal-organic framework U(bdc) (, bdc = 1,4-benzenedicarboxylate) was synthesized and its H and CH adsorption properties were investigated. Low temperature adsorption isotherms confirm strong adsorption of both gases in the framework at low pressures. gas-dosed neutron diffraction experiments with different D loadings revealed a rare example of cooperative framework contraction (Δ = -7.8%), triggered by D adsorption at low pressures. This deformation creates two optimized binding pockets for hydrogen ( = -8.6 kJ mol) per pore, in agreement with H adsorption data. Analogous experiments with CD ( = -24.8 kJ mol) and ,-dimethylformamide as guests revealed that the binding pockets in adjust by selective framework contractions that are unique for each adsorbent, augmenting individual host-guest interactions. Our results suggest that the strategic combination of binding pockets and structural flexibility in metal-organic frameworks holds great potential for the development of new adsorbents with an enhanced substrate affinity.
合成了一种新型的、空气稳定的、具有永久孔隙率的铀（IV）金属有机骨架材料U(bdc)（bdc = 1,4-苯二甲酸），并研究了其对H₂和CH₄的吸附性能。低温吸附等温线证实了在低压下该骨架材料对两种气体都有强烈吸附。不同D负载量的气体注入中子衍射实验揭示了一个罕见的协同骨架收缩（Δ = -7.8%）的例子，这是由低压下D的吸附引发的。这种变形为每个孔创造了两个优化的氢结合位点（E = -8.6 kJ mol⁻¹），与H₂吸附数据一致。以CD₄（E = -24.8 kJ mol⁻¹）和N,N-二甲基甲酰胺作为客体的类似实验表明，U(bdc)中的结合位点通过对每种吸附剂独特的选择性骨架收缩进行调整，增强了个体主客体相互作用。我们的结果表明，金属有机骨架中结合位点和结构灵活性的策略性组合对于开发具有增强底物亲和力的新型吸附剂具有巨大潜力。
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