- Benzoxazinones as potent positive allosteric AMPA receptor modulators: Part I
-
AMPA receptors (AMPARs) are an increasingly important therapeutic target in the CNS. Aniracetam, the first identified potentiator of AMPARs, led to the rigid and more potent CX614. This lead molecule was optimized in order to increase affinity towards the
- Mueller, Rudolf,Li, Yong-Xin,Hampson, Aidan,Zhong, Sheng,Harris, Clayton,Marrs, Christopher,Rachwal, Stanislaw,Ulas, Jolanta,Nielsson, Lena,Rogers, Gary
-
-
Read Online
- Effect of Functional Groups on the I2 Sorption Kinetics of Isostructural Metal–Organic Frameworks
-
In this work, the effect of functional groups on I2 sorption kinetics is investigated using two different types of isostructural metal-organic frameworks, UiO-66-X series (X = H, Br, NO2, NH2, (OH)2, and (COOH)2) and M2(m-DOBDC) series, (M = Co2+, Mg2+, and Ni2+; m-DOBDC4? = 4,6-dioxo-1,3-benzenedicarboxylate). Among the UiO-66-X series, UiO-66-(COOH)2 exhibits the fastest sorption kinetics and the highest sorption capacity due to dipole-induced dipole interactions between carboxylic acid groups and I2 molecules. In addition, faster I2 chemisorption is observed in M2(m-DOBDC) because of electrophilic aromatic substitution of m-DOBDC4? with I2. The I2 sorption mechanisms are further supported by fitting the I2 adsorption kinetics data to pseudo-first-order and pseudo-second-order kinetic models.
- Lee, Byeongchan,Park, Jinhee
-
-
Read Online
- Synthesis of fused 2-(2′-hydroxyphenyl)benzoxazole derivatives: the impact of meta-/para-substitution on fluorescence and zinc binding
-
A fused bis[2-(2′-hydroxyphenyl)benzoxazole] bis(HBO) 3 was synthesized via reaction of 4,6-dihydroxyisopthalic acid with 2-amnophenol in the presence polyphosphoric acid (PPA). In bis(HBO) 3, two benzoxazol-2-yl groups are connected via meta-phenylene, i
- Abeywickrama, Chathura S.,Pang, Yi
-
-
Read Online
- Rapid mechanochemical synthesis of metal-organic frameworks using exogenous organic base
-
Metal-organic frameworks (MOFs) bearing coordinatively unsaturated metal centers, exemplified by the MOF-74 family of frameworks, are promising for applications ranging from gas separations and storage to Lewis acid catalysis. However, the scalable synthe
- Li, Zongzhe,Milner, Phillip J.,Ng, Marcus,Wang, Zihao
-
-
Read Online
- Record High Hydrogen Storage Capacity in the Metal-Organic Framework Ni2(m-dobdc) at Near-Ambient Temperatures
-
Hydrogen holds promise as a clean alternative automobile fuel, but its on-board storage presents significant challenges due to the low temperatures and/or high pressures required to achieve a sufficient energy density. The opportunity to significantly reduce the required pressure for high density H2 storage persists for metal-organic frameworks due to their modular structures and large internal surface areas. The measurement of H2 adsorption in such materials under conditions most relevant to on-board storage is crucial to understanding how these materials would perform in actual applications, although such data have to date been lacking. In the present work, the metal-organic frameworks M2(m-dobdc) (M = Co, Ni; m-dobdc4- = 4,6-dioxido-1,3-benzenedicarboxylate) and the isomeric frameworks M2(dobdc) (M = Co, Ni; dobdc4- = 1,4-dioxido-1,3-benzenedicarboxylate), which are known to have open metal cation sites that strongly interact with H2, were evaluated for their usable volumetric H2 storage capacities over a range of near-ambient temperatures relevant to on-board storage. Based upon adsorption isotherm data, Ni2(m-dobdc) was found to be the top-performing physisorptive storage material with a usable volumetric capacity between 100 and 5 bar of 11.0 g/L at 25 °C and 23.0 g/L with a temperature swing between -75 and 25 °C. Additional neutron diffraction and infrared spectroscopy experiments performed with in situ dosing of D2 or H2 were used to probe the hydrogen storage properties of these materials under the relevant conditions. The results provide benchmark characteristics for comparison with future attempts to achieve improved adsorbents for mobile hydrogen storage applications.
- Kapelewski, Matthew T.,Run?evski, Tom?e,Tarver, Jacob D.,Jiang, Henry Z. H.,Hurst, Katherine E.,Parilla, Philip A.,Ayala, Anthony,Gennett, Thomas,Fitzgerald, Stephen A.,Brown, Craig M.,Long, Jeffrey R.
-
-
Read Online
- M2(m-dobdc) (M = Mg, Mn, Fe, Co, Ni) metal-organic frameworks exhibiting increased charge density and enhanced H2 binding at the open metal sites
-
The well-known frameworks of the type M2(dobdc) (dobdc 4- = 2,5-dioxido-1,4-benzenedicarboxylate) have numerous potential applications in gas storage and separations, owing to their exceptionally high concentration of coordinatively unsaturated metal surface sites, which can interact strongly with small gas molecules such as H2. Employing a related meta-functionalized linker that is readily obtained from resorcinol, we now report a family of structural isomers of this framework, M 2(m-dobdc) (M = Mg, Mn, Fe, Co, Ni; m-dobdc4- = 4,6-dioxido-1,3-benzenedicarboxylate), featuring exposed M2+ cation sites with a higher apparent charge density. The regioisomeric linker alters the symmetry of the ligand field at the metal sites, leading to increases of 0.4-1.5 kJ/mol in the H2 binding enthalpies relative to M 2(dobdc). A variety of techniques, including powder X-ray and neutron diffraction, inelastic neutron scattering, infrared spectroscopy, and first-principles electronic structure calculations, are applied in elucidating how these subtle structural and electronic differences give rise to such increases. Importantly, similar enhancements can be anticipated for the gas storage and separation properties of this new family of robust and potentially inexpensive metal-organic frameworks.
- Kapelewski, Matthew T.,Geier, Stephen J.,Hudson, Matthew R.,Stück, David,Mason, Jarad A.,Nelson, Jocienne N.,Xiao, Dianne J.,Hulvey, Zeric,Gilmour, Elizabeth,Fitzgerald, Stephen A.,Head-Gordon, Martin,Brown, Craig M.,Long, Jeffrey R.
-
-
Read Online
- Polyhydrazide-Based Organic Nanotubes as Efficient and Selective Artificial Iodide Channels
-
Reported herein is a series of pore-containing polymeric nanotubes based on a hydrogen-bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of about a 6.5 ? diameter, mediate highly efficient transport of diverse types of anions, rather than cations, across lipid membranes. The reported polymer channel, having an average molecular weight of 18.2 kDa and 3.6 nm in helical height, exhibits the highest anion-transport activities for iodide (EC50=0.042 μm or 0.028 mol % relative to lipid), whcih is transported 10 times more efficiently than chlorides (EC50=0.47 μm). Notably, even in cholesterol-rich environment, iodide transport activity remains high with an EC50 of 0.37 μm. Molecular dynamics simulation studies confirm that the channel is highly selective for anions and that such anion selectivity arises from a positive electrostatic potential of the central lumen rendered by the interior-pointing methyl groups.
- Aksimentiev, Aleksei,Chen, Feng,Joshi, Himanshu,Roy, Arundhati,Shen, Jie,Ye, Ruijuan,Zeng, Huaqiang
-
supporting information
p. 4806 - 4813
(2020/02/11)
-
- Separation of Xylene Isomers through Multiple Metal Site Interactions in Metal-Organic Frameworks
-
Purification of the C8 alkylaromatics o-xylene, m-xylene, p-xylene, and ethylbenzene remains among the most challenging industrial separations, due to the similar shapes, boiling points, and polarities of these molecules. Herein, we report the evaluation of the metal-organic frameworks Co2(dobdc) (dobdc4- = 2,5-dioxido-1,4-benzenedicarboxylate) and Co2(m-dobdc) (m-dobdc4- = 4,6-dioxido-1,3-benzenedicarboxylate) for the separation of xylene isomers using single-component adsorption isotherms and multicomponent breakthrough measurements. Remarkably, Co2(dobdc) distinguishes among all four molecules, with binding affinities that follow the trend o-xylene > ethylbenzene > m-xylene > p-xylene. Multicomponent liquid-phase adsorption measurements further demonstrate that Co2(dobdc) maintains this selectivity over a wide range of concentrations. Structural characterization by single-crystal X-ray diffraction reveals that both frameworks facilitate the separation through the extent of interaction between each C8 guest molecule with two adjacent cobalt(II) centers, as well as the ability of each isomer to pack within the framework pores. Moreover, counter to the presumed rigidity of the M2(dobdc) structure, Co2(dobdc) exhibits an unexpected structural distortion in the presence of either o-xylene or ethylbenzene that enables the accommodation of additional guest molecules.
- Gonzalez, Miguel I.,Kapelewski, Matthew T.,Bloch, Eric D.,Milner, Phillip J.,Reed, Douglas A.,Hudson, Matthew R.,Mason, Jarad A.,Barin, Gokhan,Brown, Craig M.,Long, Jeffrey R.
-
p. 3412 - 3422
(2018/03/13)
-
- Highly Ordered Nanoporous Films from Supramolecular Diblock Copolymers with Hydrogen-Bonding Junctions
-
We designed efficient precursors that combine complementary associative groups with exceptional binding affinities and thiocarbonylthio moieties enabling precise RAFT polymerization. Well defined PS and PMMA supramolecular polymers with molecular weights up to 30 kg mol?1are synthesized and shown to form highly stable supramolecular diblock copolymers (BCPs) when mixed, in non-polar solvents or in the bulk. Hierarchical self-assembly of such supramolecular BCPs by thermal annealing affords morphologies with excellent lateral order, comparable to features expected from covalent diblock copolymer analogues. Simple washing of the resulting materials with protic solvents disrupts the supramolecular association and selectively dissolves one polymer, affording a straightforward process for preparing well-ordered nanoporous materials without resorting to crosslinking or invasive chemical degradations.
- Montarnal, Damien,Delbosc, Nicolas,Chamignon, Cécile,Virolleaud, Marie-Alice,Luo, Yingdong,Hawker, Craig J.,Drockenmuller, Eric,Bernard, Julien
-
p. 11117 - 11121
(2016/07/06)
-
- Inclusion complex containing epoxy resin composition for semiconductor encapsulation
-
The invention is an epoxy resin composition for sealing a semiconductor, including (A) an epoxy resin and (B) a clathrate complex. The clathrate complex is one of (b1) an aromatic carboxylic acid compound, and (b2) at least one imidazole compound represented by formula (II): wherein R2 represents a hydrogen atom, C1-C10 alkyl group, phenyl group, benzyl group or cyanoethyl group, and R3 to R5 represent a hydrogen atom, nitro group, halogen atom, C1-C20 alkyl group, phenyl group, benzyl group, hydroxymethyl group or C1-C20 acyl group. The composition has improved storage stability, retains flowability when sealing, and achieves an effective curing rate applicable for sealing delicate semiconductors.
- -
-
-
- Non-aggregational aromatic oligoamide macrocycles
-
Attaching peripheral amide groups to the backbone of cyclic aromatic oligoamides 1 leads to new macrocycles 2 that show drastically changed behavior including modest yields of formation and no tendency to aggregate while maintaining a rigid backbone and a
- Wu, Xiangxiang,Liang, Guoxing,Ji, Gang,Fun, Hoong-Kun,He, Lan,Gong, Bing
-
supporting information; experimental part
p. 2228 - 2230
(2012/03/09)
-
- A highly stable, six-hydrogen-bonded molecular duplex
-
This paper describes the design, synthesis, and characterization of a hydrogen-bonded molecular duplex (3·4). Two oligoamide molecular strands, 3 and 4, with the complementary hydrogen-bonding sequences ADAADA and DADDAD, respectively, were found to form
- Zeng, Huaqiang,Miller, Rebecca S.,Flowers II, Robert A.,Gong, Bing
-
p. 2635 - 2644
(2007/10/03)
-
- Process for dicarboxylating dihydric phenols
-
A process is disclosed for dicarboxylating dihydric phenols, notably those where the hydroxyl groups are in the para or the ortho position vis-+E,gra a+EE -vis one another. More particularly, the invention pertains to a process for preparing 2,5-dihydroxy
- -
-
-
