An rht-type metal-organic framework (MOF) prepared from M(2)(carboxylate)(4) (M = Cu, Co) paddlewheel clusters and a flexible C(3)-symmetric hexacarboxylate ligand with acylamide groups exhibits larger CO(2) uptake, an enhanced heat of adsorption, and higher selectivity toward CO(2)/N(2) in comparison with what was previously observed for an analogous MOF with alkyne groups.
The reaction of [Cp*Fe(eta5-P5)] with Cu(I)Cl in solvent mixtures of CH2Cl2/CH3CN leads to the formation of entirely inorganic fullerene-like molecules of the formula [[Cp*Fe(eta5:eta1:eta1:eta1:eta1:eta1-P5)]12[CuCl]10[Cu2Cl3]5[Cu(CH3CN)2]5] (1) possessing 90 inorganic core atoms. This compound represents a structural motif similar to that of C60: cyclo-P5 rings of [Cp*Fe(eta5-P5)] molecules are surrounded by six-membered P4Cu2 rings that result from the coordination of each of the phosphorus lone pairs to CuCl metal centers, which are further coordinated by P atoms of other cyclo-P5 rings. Thus, five- and six-membered rings alternate in a manner comparable to that observed in the fullerene molecules. The so-formed half shells are joined by [Cu2Cl3]- as well as by [Cu(CH3CN)2]+ units. The spherical body has an inside diameter of 1.25 nanometers and an outside diameter of 2.13 nanometers, which is about three times as large as that of C60.
Based upon the (3,6)-connected metal-organic framework {Cu(L1)·2H(2)O·1.5DMF}(∞) (L1 = 5-(pyridin-4-yl)isophthalic acid) (SYSU, for Sun Yat-Sen University), iso-reticular {Cu(L2)·DMF}(∞) (L2 = 5-(pyridin-3-yl)isophthalic acid) (NJU-Bai7; NJU-Bai for Nanjing University Bai group) and {Cu(L3)·DMF·H(2)O}(∞) (L3 = 5-(pyrimidin-5-yl)isophthalic acid) (NJU-Bai8) were designed by shifting the coordination sites of ligands to fine-tune pore size and polarizing the inner surface with uncoordinated nitrogen atoms, respectively, with almost no changes in surface area or porosity. Compared with those of the prototype SYSU, both the adsorption enthalpy and selectivity of CO(2) for NJU-Bai7 and NJU-Bai8 have been greatly enhanced, which makes NJU-Bai7 and NJU-Bai8 good candidates for postcombustion CO(2) capture. Notably, the CO(2) adsorption enthalpy of NJU-Bai7 is the highest reported so far among the MOFs without any polarizing functional groups or open metal sites. Meanwhile, NJU-Bai8 exhibits high uptake of CO(2) and good CO(2)/CH(4) selectivity at high pressure, which are quite valuable characteristics in the purification of natural gases.
A new microporous metal-organic framework Cu(2)(EBTC)(H(2)O)(2) x xG (EBTC = 1,1'-ethynebenzene-3,3',5,5'-tetracarboxylate; G = guest molecule) was rationally designed with a NbO net, exhibiting significantly high acetylene storage of 252 and 160 cm(3) g(-1) at 273 and 295 K under 1 bar, respectively.
An amide-inserted metal-organic framework (NJU-Bai3) presents high storage and high selectivity toward CO(2) and combines these two interesting characters which strongly support our expectation that amide groups can significantly enhance the CO(2) binding ability and selectivity of MOFs.
We developed a physical technique combining an on-line sputtering/evaporation process with an integrated nanocluster deposition process to prepare core-shell-type nanoparticles. High-magnetic-moment (Fe60Co40)coreAushell and (Fe60Co40)coreAgshell superparamagnetic nanoparticles with controllable particle size of 10–20 nm and Au∕Ag shell thickness of 1–3 nm were prepared by using this method. Au shell is not only functional for the potential biocompatibility but also the key to prevent the oxidation of FeCo nanoparticles. Saturation magnetization of (Fe60Co40)coreAushell nanoparticles was found three times higher than that of iron oxide nanoparticles. This technique enables us to control independently the dimensions of core and shell and select individually materials for core and shell for any other core-shell-type nanoparticles.
CO2 capture science and technology, particularly for the post-combustion CO2 capture, has become one of very important research fields, due to great concern of global warming. Metal-organic frameworks (MOFs) with a unique feature of structural fine-tunability, unlike the traditional porous solid materials, can provide many and powerful platforms to explore high-performance adsorbents for post-combustion CO2 capture. Until now, several strategies for finely tuning MOF structures have been developed, in which either the larger quadrupole moment and polarizability of CO2 are considered: metal ion change (I), functional groups attachment (II) and functional group insertion (III), vary the electronic nature of the pore surface; or targeting the smaller kinetic diameter of CO2 over N2 is focused on: framework interpenetration (IV), ligand shortening (V) and coordination site shifting (VI) contract the pore size of frameworks to improve their CO2 capture properties. In this review, from the viewpoint of synthetic materials scientists/chemists, we would like to introduce and summarize these strategies based upon recent work published by other groups and ourselves.
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