铁脂质体/水分配系数测定及影响因素考察

基于PAF-301分子模型通过Li 掺杂或B取代等模式设计了几种新型多孔芳香骨架(PAFs)材料, 采用量子力学和分子力学方法对新材料的储氢性能进行研究. 由量子力学计算得到了不同分子片段与H₂之间的结合能, 并结合DDEC方法计算了各分子片段的原子电荷分布. 利用巨正则蒙特卡洛(GCMC)模拟方法计算了77和298 K下H₂在不同PAFs材料中的吸附平衡性质. 结果表明, H₂直接与苯环的结合能较低, 但掺杂Li 原子能够提高H₂与六元环的结合能, 同时Li 原子体现出较高的正电性质, B原子取代苯环中的两个C原子后, 使得原有C原子电负性增强; 77 K下PAF-301Li 具有最高的储氢性能, 而PAF-C₄B₂H₄-Li₂-Si 和PAF-C₄B₂H₄-Li₂-Ge体现出较好的常温储氢性能, 各种材料的常温储氢性能远低于其低温储氢性能. 通过77 K下H₂在PAFs材料中的等位能面分布和吸附平衡质心密度分布对H₂在PAFs 材料中的优先吸附位置进行分析, 发现在PAF-301 和PAF-301Li 骨架中, 由于中心能量较低的等位能区域范围较宽, H₂在其中存在四个明显的吸附高密度分布区域, 而其它三种PAFs晶胞中心能量较低的等位能区域范围较窄, 使得H₂在其中只存在两个明显的吸附高密度分布区域.     

一系列基于混合配体策略构筑的金属有机骨架的合成、结构及性质

通过简单高效的醛酮缩合反应,合成了碱性配体2,6-二（4-吡啶基亚甲基）环己酮（BPCH）,采用3种芳香羧酸配体：对苯二甲酸（H₂TP）、间苯二甲酸（H₂IP）和均苯三甲酸（H₃TMA）,以混合配体策略制备了7例金属有机骨架（MOFs）。用单晶X射线衍射、红外光谱、粉末X射线衍射和热重分析对其进行表征并分析其拓扑结构。MOFs1、2、3均呈现为多样的三维结构,MOFs4~7表现为同构的二维结构。荧光测试结果显示该类化合物对Fe³⁺有较好的荧光猝灭效应,同时对于染料具有一定的吸附能力。     

二维TiC 层表面H2的化学吸附与物理吸附

第一性原理计算研究发现由于二维TiC 单原子层具有高的比表面积与大量的暴露在表面的Ti 原子,其是一种非常有潜力的储氢材料. 计算结果显示H₂可以在二维TiC 单原子层表面进行物理吸附与化学吸附. 其中化学吸附能为每个氢分子0.36 eV,物理吸附能是每个氢分子0.09 eV. 覆盖度为1和1/4层（ML）时,H₂分子在二维TiC 单原子层表面的离解势垒分别为1.12 和0.33 eV. 因此,除了物理吸附与化学吸附,TiC 表面还存在H单原子吸附. 最大的H₂储存率可以达到7.69%（质量分数）. 其中,离解的H原子、化学吸附的H₂、物理吸附的H₂的储存率分别为1.54%、3.07%、3.07%. 符合Kubas吸附特征的储存率为3.07%. 化学吸附能随覆盖度的变化非常小,这有利于H₂分子的吸附与释放.     

一个微孔钴基金属有机骨架的合成及其选择性气体吸附

利用硝酸钴与配体5,5''-di(1H-1,2,4-triazol-1-yl)-(1,1''-biphenyl)-2,2''-dicarboxylic acid (H₂DTBDA)进行溶剂热反应,制备了一个结构新颖的金属有机骨架{[Co(DTBDA)]₂·DMF·MeOH}_n (FJI-H37)。FJI-H37不仅具有适合气体分子吸附的0.69 nm的微孔,还具有良好的热稳定性及有机溶剂容忍性。气体吸附测试表明FJI-H37不仅能从C₂H₂/CO₂(体积比50:50)混合气中选择性吸附C₂H₂,还可以从CO₂/N₂(体积比15:85)和CO₂/CH₄(体积比50:50)混合气中选择性捕获CO₂;固定床突破实验进一步证实了其高效的气体分离能力。     

一例互穿的阴离子型In（Ⅲ）金属有机骨架用于选择性检测水中Fe3+离子

作为一类新型多孔材料,金属有机骨架（MOFs）常被开发作为荧光传感器用来监测水中的污染物,开发稳定且易制备的MOFs材料实现选择性检测有毒的Fe³⁺仍具有较高挑战。本工作中,我们报道一例水稳定的二重穿插In（Ⅲ）基MOF：（NH₂Me₂）[In （fdc）₂]·2H₂O （BUT-205,BUT代表北京工业大学,H₂fdc=呋喃-2,5-二羧酸）。BUT-205的构筑采用生物质衍生配体,其结构通过单晶X射线衍射确立。这个材料可作为高效的水相Fe³⁺离子传感器,具有高的灵敏度和选择性。检测限达到1.3 μmol·L^-1,低于美国环保局规定的饮用水中安全标准（15.7 μmol·L^-1）,并且该传感材料可以回收利用至少4次。     

中心金属离子改变诱导MOFs结构和光催化性能的改变

在相同的水热条件下,铜盐、钴盐分别和配体H₂PPCA（H₂PPCA=5-pyrazin-2-yl-1H-pyrazole-3-carboxylic acid）发生反应,生成了2个结构截然不同的金属有机配合物,分别是[Cu（PPCA）（H₂O）]·H₂O（HPU-7）和{[Co（PPCA）（H₂O）]·H₂O}_n（HPU-8）。HPU-7是由CuCl₂·2H₂O与配体在160℃下反应而成的,它呈现出零维的双核铜单元结构。HPU-8是由Co（NO₃）₂·6H₂O与配体在160℃下反应生成的,它呈现出由双核钴单元与配体的骨架相连而成的4,4-连接的二维层结构。中心金属离子的改变导致了不同结构MOF的形成,并且它们的电化学性能研究表明它们是很好的半导体材料,它们都对亚甲基蓝（MB）具有较好的光催化效果。     

中心金属离子改变诱导MOFs结构和光催化性能的改变

在相同的水热条件下,铜盐、钴盐分别和配体H₂PPCA（H₂PPCA=5-pyrazin-2-yl-1H-pyrazole-3-carboxylic acid）发生反应,生成了2个结构截然不同的金属有机配合物,分别是[Cu（PPCA）（H₂O）]·H₂O（HPU-7）和{[Co（PPCA）（H₂O）]·H₂O}_n（HPU-8）。HPU-7是由CuCl₂·2H₂O与配体在160℃下反应而成的,它呈现出零维的双核铜单元结构。HPU-8是由Co（NO₃）₂·6H₂O与配体在160℃下反应生成的,它呈现出由双核钴单元与配体的骨架相连而成的4,4-连接的二维层结构。中心金属离子的改变导致了不同结构MOF的形成,并且它们的电化学性能研究表明它们是很好的半导体材料,它们都对亚甲基蓝（MB）具有较好的光催化效果。     

互穿结构及混合配体对金属-有机骨架材料分离性能的影响

在以前的工作中, 我们利用蒙特卡洛和分子动力学模拟计算了具有互穿性结构及混合配体的金属-有机骨架材料(metal-organic frameworks, MOFs)分离CH₄/H₂的吸附选择性及扩散选择性. 研究了材料的互穿结构及混合配体对材料用于分离CH₄/H₂性能的影响. 在本工作中, 我们将以前的工作进行了扩展, 详细研究了材料的互穿结构及混合配体对材料用于分离CO₂/CH₄, CO₂/N₂和CO₂/H₂等含有CO₂的气体混合物性能的影响. 此外, 为了进一步阐明材料的结构对于其分离性能的影响, 我们亦研究了材料用于分离CH₄/H₂及CH₄/N₂. 从我们的结果可以看出, 相比无互穿结构的MOFs材料, 具有互穿结构的MOFs材料对所研究的所有混合气体的渗透选择性明显提高. 这是因为具有互穿结构的MOFs材料对混合气体的吸附选择性明显高于无互穿结构的MOFs材料. 结果表明, 如果将材料作为膜用于气体混合物分离, 使材料产生互穿结构是提高材料分离性能的一个很好的策略.     

一个微孔钴基金属有机骨架的合成及其选择性气体吸附

利用硝酸钴与配体5，5''-di (1H-1，2，4-triazol-1-yl)-(1，1''-biphenyl)-2，2''-dicarboxylic acid (H₂DTBDA)进行溶剂热反应，制备了一个结构新颖的金属有机骨架{[Co (DTBDA)]₂·DMF·MeOH}_n (FJI-H37)。FJI-H37不仅具有适合气体分子吸附的0.69 nm的微孔，还具有良好的热稳定性及有机溶剂容忍性。气体吸附测试表明FJI-H37不仅能从C₂H₂/CO₂(体积比50∶50)混合气中选择性吸附C₂H₂，还可以从CO₂/N₂(体积比15∶85)和CO₂/CH₄(体积比50∶50)混合气中选择性捕获CO₂；固定床突破实验进一步证实了其高效的气体分离能力。     

一个微孔钴基金属有机骨架的合成及其选择性气体吸附

利用硝酸钴与配体5，5''-di (1H-1，2，4-triazol-1-yl)-(1，1''-biphenyl)-2，2''-dicarboxylic acid (H₂DTBDA)进行溶剂热反应，制备了一个结构新颖的金属有机骨架{[Co (DTBDA)]₂·DMF·MeOH}_n (FJI-H37)。FJI-H37不仅具有适合气体分子吸附的0.69 nm的微孔，还具有良好的热稳定性及有机溶剂容忍性。气体吸附测试表明FJI-H37不仅能从C₂H₂/CO₂(体积比50∶50)混合气中选择性吸附C₂H₂，还可以从CO₂/N₂(体积比15∶85)和CO₂/CH₄(体积比50∶50)混合气中选择性捕获CO₂；固定床突破实验进一步证实了其高效的气体分离能力。     

Adsorption of RDX and TATP on IRMOF-1: an ab initio study

The adsorption of 1,3,5-trinitro-s-triazine (RDX) and triacetone triperoxide (TATP) on representative fragments of metal organic framework (IRMOF-1) was studied at the B3LYP/6-31G(d) level of theory. For examined adsorbates several possible adsorption positions toward the IRMOF-1 fragments were found. The adsorption strength of the adsorbate on IRMOF-1 is largely affected by the geometry of the active site of IRMOF-1 which controls the orientation of the target molecule with respect to the IRMOF-1 fragment. The calculations show that the adsorption on these fragments occurs due to the formation of hydrogen bonds between the molecular C–H groups and the oxygen atoms of IRMOF-1. The RDX and TATP molecules are the most strongly adsorbed on the linker fragment of IRMOF-1. This type of adsorption results in the polarization of RDX and TATP on the IRMOF-1 fragments. The interaction energy of two most stable RDX-, and TATP-IRMOF-1 adsorption systems are ?9.8 and ?12.8 kcal/mol, respectively. It can be concluded that the 1,4-benzenedicarboxylate site of IRMOF-1 shows the stronger molecular adsorption of RDX and TATP than the site containing [Zn₄O(CO₂)₆] and also it is characterized by higher reactivity than the other considered sites. The binding of studied explosive molecules to IRMOF-1 consists of interplay between attractive interactions between the target molecule and MOF as well as the shielding by the IRMOF-1 fragment induced by the molecular adsorption. The relative importance of these effects depends on the chemical nature, the size, and the shape of the molecule and MOF. Small-size molecules require smaller space for the adsorption and also they are less shielded by the sizeable adsorbent. So they interact better when adsorbed on larger IRMOF-1 fragment. On the other side, larger molecules show higher adsorption strength with small fragments of IRMOF-1.     

Polarity-Induced Excited-State Intramolecular Proton Transfer (ESIPT) in a Pair of Supramolecular Isomeric Multifunctional Dynamic Metal–Organic Frameworks

A pair of supramolecular isomers of Cd^II-based MOF have been synthesized by utilizing a flexible N,N′-donor linker and a dicarboxylate with ESIPT (excited-state intramolecular proton transfer) fluorophore by varying the reaction media. One of the MOFs has a 3D four-fold interpenetrating framework with guest solvent in the structure that undergoes a solvent-dependent crystalline-to-crystalline structural transformation, which has been extensively studied by powder XRD and IR spectroscopy. The other MOF is structurally rigid in nature and has a two-fold interpenetrating structure without any guest molecules. Both the compounds show moderate CO₂ adsorption and one of them, the MOF with the four-fold interpenetrating structure, also shows moderately high H₂ adsorption. Furthermore, both the compounds show interesting luminescence behavior. In the solid state, the two compounds show single-peak spectra, whereas upon suspension of these compounds in polar solvents, the maxima split into two peaks with a large Stokes shift. On the other hand, in nonpolar solvents, only one emission maximum is observed. This solvatochromic dual-emission phenomenon is due to ESIPT, which has been extensively studied.     

Room temperature synthesis of metal-organic frameworks: MOF-5, MOF-74, MOF-177, MOF-199, and IRMOF-0

Room temperature synthesis of metal-organic frameworks (MOFs) has been developed for four well-known MOFs: MOF-5, MOF-74, MOF-177, and MOF-199. A new isoreticular metal framework (IRMOF), IRMOF-0, having the same cubic topology as MOF-5, has been synthesized from acetylenedicarboxylic acid using this method to accommodate the thermal sensitivity of the linker. Despite acetylenedicarboxylate being the shortest straight linker that can be made into an IRMOF, IRMOF-0 forms as a doubly interpenetrating structure, owing to the rod-like nature of the linker.     

Discovery of Complex Binding and Reaction Mechanisms from Ternary Gases in Rare Earth Metal–Organic Frameworks

Understanding the selectivity of metal–organic frameworks (MOFs) to complex acid gas streams will enable their use in industrial applications. Herein, ab initio molecular dynamic simulations (AIMD) were used to simulate ternary gas mixtures (H₂O-NO₂-SO₂) in rare earth 2,5-dihydroxyterephthalic acid (RE-DOBDC) MOFs. Stronger H₂O gas-metal binding arose from thermal vibrations in the MOF sterically hindering access of SO₂ and NO₂ molecules to the metal sites. Gas-gas and gas-linker interactions within the MOF framework resulted in the formation of multiple secondary gas species including HONO, HNO₂, NOSO, and HNO₃⁻. Four gas adsorption sites were identified along with a new de-protonation reaction mechanism not observable through experiment. This study not only provides valuable information on competitive gas binding energies in the MOF, it also provides important chemical insights into transient chemical reactions and mechanisms.     

Advances of Metal‐Organic Frameworks in Energy and Environmental Applications

Nowadays, energy shortage and environmental pollution issues are increasingly severe and urgent to be solved. The effective storage and use of environmentally friendly fuels and removal of harmful gases from the environment are great challenges and of great importance both for the environment protection and for human health. Porous metal‐organic frameworks (MOFs) are highly ordered crystalline materials formed by the self‐assembly process of metal ions and organic ligands. Their good features such as ultrahigh porosity, large surface area, structural diversity and functionalities make them promising candidates for applications in energy and environmental fields. MOF thin films and MOF composites have also been investigated to further enhance the properties and introduce new functionalities. This review provides an overview of the synthesis methods of pristine MOFs, MOF thin films and MOF composites, and significant advances of MOFs in energy and environment applications such as energy storage (H₂, CH₄), CO₂ capture and separation, adsorption removal and sensing of harmful gases in the environment.     

Functionality proportion and corresponding stability study of multivariate metal-organic frameworks

Zn-based multivariate metal-organic frameworks (MTV-MOFs) with different functionality proportions and with different thermal and chemical stabilities can be obtained by employing the appropriate synthesis method.     

Crystal Dynamics in Multi‐stimuli‐Responsive Entangled Metal–Organic Frameworks

An understanding of solid‐state crystal dynamics or flexibility in metal–organic frameworks (MOFs) showing multiple structural changes is highly demanding for the design of materials with potential applications in sensing and recognition. However, entangled MOFs showing such flexible behavior pose a great challenge in terms of extracting information on their dynamics because of their poor single‐crystallinity. In this article, detailed experimental studies on a twofold entangled MOF ( f‐MOF‐1) are reported, which unveil its structural response toward external stimuli such as temperature, pressure, and guest molecules. The crystallographic study shows multiple structural changes in f‐MOF‐1 , by which the 3 D net deforms and slides upon guest removal. Two distinct desolvated phases, that is, f‐MOF‐1 a and f‐MOF‐1 b , could be isolated; the former is a metastable one and transformable to the latter phase upon heating. The two phases show different gated CO₂ adsorption profiles. DFT‐based calculations provide an insight into the selective and gated adsorption behavior with CO₂ of f‐MOF‐1 b . The gate‐opening threshold pressure of CO₂ adsorption can be tuned strategically by changing the chemical functionality of the linker from ethanylene (?CH₂?CH₂?) in f‐MOF‐1 to an azo (?N=N?) functionality in an analogous MOF, f‐MOF‐2 . The modulation of functionality has an indirect influence on the gate‐opening pressure owing to the difference in inter‐net interaction. The framework of f‐MOF‐1 is highly responsive toward CO₂ gas molecules, and these results are supported by DFT calculations.     

A Hydrophobic Metal–Organic Framework Based on Cubane‐Type [Co4(μ3‐F)3(μ3‐SO4)]3+ Clusters for Gas Storage and Adsorption Selectivity of Benzene over Cyclohexane

Hydrophobic metal‐organic frameworks (MOFs) not only have high water stability, but also exhibit high adsorption capacity towards organic molecules, in particular hydrocarbons. Herein we report a rare metal fluoride organic framework MFOF‐1 with high hydrophobicity, which is constructed from unprecedented fluoride‐ and sulfate‐bridged cubane‐type tetranuclear cobalt clusters. MFOF‐1 consists of three types of polyhedral cages with face‐sharing configurations, and possesses a novel (3,9)‐connected 3D+3D→3D self‐interpenetrating array or the rare pyr topology. MFOF‐1 shows high thermal stability and high stability in water and even acid/base aqueous solutions, and exhibits rather high H₂ and CO₂ storage capacities at ambient pressure. Remarkably, MFOF‐1 shows little adsorption of water but considerably high uptakes of methanol, n‐hexane, cyclohexane, and benzene, and exhibits a certain degree of adsorption selectivity of benzene over cyclohexane.     

On the nature of the interaction between H2 and metal-organic frameworks

The mechanism of adsorption of molecular hydrogen (H₂) on IRMOF-1 is studied at the MP2 level. The role of the two principal MOF components, the inorganic connector and the organic linker, for H₂ adsorption is evaluated. Correlation methods and large basis sets are necessary to describe correctly the weak interactions (London dispersion) and to account for the polarisability of H₂. We proof that the electrostatic interactions have a negligible contribution to the interaction energy and the adsorption mechanism is governed by London dispersion (3–5 kJ mol^?1).     

Charge Control in Two Isostructural Anionic/Cationic CoII Coordination Frameworks for Enhanced Acetylene Capture

Two isostructural Co^II‐based metal–organic frameworks (MOFs) with the opposite framework charges have been constructed, which can be simply controlled by changing the tetrazolyl or triazolyl terminal in two bifunctional ligands. Notably, the cationic MOF 2 can adsorb much more C₂H₂ than the anionic MOF 1 with an increase of 88 % for C₂H₂ uptake at 298 K in spite of more active nitrogen sites in 1 . Theoretical calculations indicate that both nitrate and triazolyl play vital roles in C₂H₂ binding and the C₂H₂ adsorption isotherm confirms that the enhanced C₂H₂ uptake for 2 (225 and 163 cm³g^?1 at 273 and 298 K) is exceptionally high for MOF materials without open metal sites or uncoordinated polar atom groups on the frameworks.