Engineering membranes with macrocycles for precise molecular separations

The crystal structure of VOBDC (BDC = 1,4-benzenedicarboxylate) has a 1-dimensional channel system with apertures of ∼8 Å, and shows remarkable flexibility upon adsorption/desorption of various guest molecules in the channels. VOBDC can selectively and rapidly adsorb organic molecules containing sulfur on exposure to a 5% CH4/He stream with different contents of thiophene or dimethyl sulfide at ambient temperature. Selective uptake of thiophene from liquid octane with thiophene concentrations from 2000 ppmw down to 100 ppmw is also observed. X-ray crystallographic data show that the adsorbed thiophene molecules adopt a herringbone packing arrangement within the channels of VOBDC while adsorbed dimethyl sulfide molecules are disordered among several positions in the channels with the sulfur atoms pointing toward the channel walls. The observed adsorptive capacities for thiophene and dimethyl sulfide are 155 mg and 208 mg sulfur per gram of VOBDC, respectively, consistent with the crystal structure data.

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Molecular Container Assembly Capable of Controlling Binding and Release of Its Guest Molecules: Reversible Encapsulation of Organic Molecules in Sodium Ion Complexed Cucurbituril

Journal of the American Chemical Society ◽

10.1021/ja962071x ◽

1996 ◽

Vol 118 (40) ◽

pp. 9790-9791 ◽

Cited By ~ 240

Author(s):

You-Moon Jeon ◽

Jaheon Kim ◽

Dongmok Whang ◽

Kimoon Kim

Keyword(s):

Organic Molecules ◽

Sodium Ion ◽

Guest Molecules ◽

Molecular Container

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Small Molecules, Non-Covalent Interactions, and Confinement

Molecules ◽

10.3390/molecules25143311 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3311 ◽

Cited By ~ 5

Author(s):

Gerd Buntkowsky ◽

Michael Vogel

Keyword(s):

Role Models ◽

Organic Molecules ◽

Guest Molecules ◽

Analytical Technique ◽

Host Interactions ◽

Functionalized Mesoporous Silica ◽

Current Trends ◽

Physico Chemical ◽

Non Covalent Interactions ◽

Covalent Interactions

This review gives an overview of current trends in the investigation of small guest molecules, confined in neat and functionalized mesoporous silica materials by a combination of solid-state NMR and relaxometry with other physico-chemical techniques. The reported guest molecules are water, small alcohols, and carbonic acids, small aromatic and heteroaromatic molecules, ionic liquids, and surfactants. They are taken as characteristic role-models, which are representatives for the typical classes of organic molecules. It is shown that this combination delivers unique insights into the structure, arrangement, dynamics, guest-host interactions, and the binding sites in these confined systems, and is probably the most powerful analytical technique to probe these systems.

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Combining machine learning and high-throughput experimentation to discover photocatalytically active organic molecules

Chemical Science ◽

10.1039/d1sc02150h ◽

2021 ◽

Author(s):

Xiaobo Li ◽

Phillip M. Maffettone ◽

Yu Che ◽

Tao Liu ◽

Linjiang Chen ◽

...

Keyword(s):

Machine Learning ◽

High Throughput ◽

Organic Molecules ◽

Chemical Compounds ◽

Structure Property ◽

Design Rules ◽

Useful Components ◽

High Throughput Experimentation ◽

Unique Chemical

Light-absorbing organic molecules are useful components in photocatalysts, but it is difficult to formulate reliable structure-property design rules. More than 100 million unique chemical compounds are documented in the PubChem...

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Tuning of the Cavity of Water-Soluble Thiacalix[4]arene for the Control of Inclusion Ability Toward Water-Miscible Organic Molecules

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20041080 ◽

2004 ◽

Vol 69 (5) ◽

pp. 1080-1096 ◽

Cited By ~ 5

Author(s):

Noriyoshi Kon ◽

Nobuhiko Iki ◽

Yuichiro Sano ◽

Satoshi Ogawa ◽

Chizuko Kabuto ◽

...

Keyword(s):

Guest Molecule ◽

Organic Molecules ◽

Hydrophobic Effect ◽

Binding Constants ◽

Water Soluble ◽

Main Role ◽

Diethyl Ketone ◽

Guest Molecules ◽

X Ray ◽

H Nmr

Inclusion abilities of water-soluble thiacalix[4]arenetetrasulfonate (3) and mono-O-carboxymethylated derivatives 5 and 6 toward water-miscible organic molecules such as alcohols, ketones, and nitriles in water were investigated by 1H NMR. The limit chemical shift change of the guest upon inclusion in the host suggested that the hosts regioselectively encapsulate the guests from the side of aliphatic moiety. Large guests such as pentan-1-ol showed folding of the alkyl chain to be included inside the cavity. On the other hand, mono-O-substituted 6 included a guest molecule less deep in the cavity than 3 did. Binding constants (K) of 3 toward guest molecules increased with hydrophobicity of the guest, suggesting that hydrophobic effect plays a main role for the complexation. On the contrary, mono-O-carboxymethyl derivatives 5 and 6 showed the opposite dependency of stability on hydrophobicity; higher affinities toward less hydrophobic guests. Among the guests examined, the smallest entities such as CH3OH and CH3CN were best included in 5 with the highest binding constant ever reported (K > 102 M-1). It was concluded that introduction of the carboxymethyl group into one of the phenolic OH of thiacalix[4]arene led to tuning of the cavity shape for stereospecific inclusion of small guests. The tuning of cavity by the O-alkylation was actually confirmed by X-ray crystal analysis of a complex of 5 with diethyl ketone.

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High Resolution Replication of Organoclay Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055126 ◽

1982 ◽

Vol 40 ◽

pp. 576-577

Author(s):

W. W. Barker ◽

W. E. Rigsby ◽

V. J. Hurst ◽

W. J. Humphreys

Keyword(s):

Clay Mineral ◽

Organic Molecule ◽

Organic Molecules ◽

X Ray Diffraction ◽

Xrd Pattern ◽

X Ray ◽

Naturally Occurring ◽

Silicate Layers ◽

Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

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Direct phase determination in electron crystallography: small organic molecules

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130468 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1166-1167

Author(s):

Douglas L. Dorset

Keyword(s):

Organic Molecules ◽

Data Sets ◽

Temperature Structure ◽

3D Analysis ◽

Intensity Data ◽

Electron Crystallography ◽

Phase Determination ◽

Measured Intensity ◽

3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

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