Chemical reactivity of C–F bonds attached to graphene with diamines depending on their nature and location

ATP-binding cassette (ABC) transporters form a large superfamily of ATP-dependent protein complexes that mediate transport of a vast array of substrates across membranes. The 14 currently available structures of ABC transporters have greatly advanced insight into the transport mechanism and revealed a tremendous structural diversity. Whereas the domains that hydrolyze ATP are structurally related in all ABC transporters, the membrane-embedded domains, where the substrates are translocated, adopt four different unrelated folds. Here, we review the structural characteristics of ABC transporters and discuss the implications of this structural diversity for mechanistic diversity.

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Hydration of a sulfuric acid–oxalic acid complex: acid dissociation and its atmospheric implication

RSC Advances ◽

10.1039/c5ra06116d ◽

2015 ◽

Vol 5 (60) ◽

pp. 48638-48646 ◽

Cited By ~ 34

Author(s):

Shou-Kui Miao ◽

Shuai Jiang ◽

Jiao Chen ◽

Yan Ma ◽

Yu-Peng Zhu ◽

...

Keyword(s):

Density Functional Theory ◽

Sulfuric Acid ◽

Oxalic Acid ◽

Density Functional ◽

Structural Characteristics ◽

Acid Dissociation ◽

Acid Complex ◽

Functional Theory ◽

Insight Into

We have investigated structural characteristics and thermodynamics of the hydration of a sulfuric acid–oxalic acid complex using density functional theory to gain insight into the ternary nucleation and its atmospheric implication.

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A Graph-Convolutional Neural Network Model for the Prediction of Chemical Reactivity

10.26434/chemrxiv.7163189 ◽

2018 ◽

Author(s):

Connor W. Coley ◽

Wengong Jin ◽

Luke Rogers ◽

Timothy F. Jamison ◽

Tommi S Jaakkola ◽

...

Keyword(s):

Chemical Reactivity ◽

Neural Model ◽

Major Product ◽

Formal Training ◽

Learning Approach ◽

Learning Approaches ◽

Additional Insight ◽

Patent Literature ◽

Two Stages ◽

Insight Into

We present a supervised learning approach to predict the products of organic reactions given their reactants, reagents, and solvent(s). The prediction task is factored into two stages comparable to manual expert approaches: considering possible sites of reactivity and evaluating their relative likelihoods. By training on hundreds of thousands of reaction precedents covering a broad range of reaction types from the patent literature, the neural model makes informed predictions of chemical reactivity. The model predicts the major product correctly over 85% of the time requiring around 100 ms per example, a significantly higher accuracy than achieved by previous machine learning approaches, and performs on par with expert chemists with years of formal training. We gain additional insight into predictions via the design of the neural model, revealing an understanding of chemistry qualitatively consistent with manual approaches.

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Effect of sodium hypochlorite concentration during pre-treatment on isolation of nanocrystalline cellulose from Leucaena leucocephala (Lam.) mature pods

BioResources ◽

10.15376/biores.16.2.3137-3158 ◽

2021 ◽

Vol 16 (2) ◽

pp. 3137-3158

Author(s):

Aida Safina Aridi ◽

Nyuk Ling Chin ◽

Nur Akmal Ishak ◽

Nor Nadiah Mohamad Yusof ◽

Kazunori Kadota ◽

...

Keyword(s):

Sodium Hypochlorite ◽

Leucaena Leucocephala ◽

Alkali Treatment ◽

Structural Characteristics ◽

Alkaline Treatment ◽

Nanocrystalline Cellulose ◽

Raw Material ◽

Pre Treatment ◽

Bleaching Treatment ◽

Insight Into

Mature pods of Leucaena leucocephala (Lam.) de Wit were utilized as raw material for nanocrystalline cellulose (NCC) production. NCC’s isolation begins with L. leucocephala fiber’s alkaline treatment with sodium hydroxide, followed by bleaching treatment at three different percentages (3%, 5%, and 7%) of sodium hypochlorite. Acid hydrolysis was then conducted to obtain NCC, which was comprehensively characterized in terms of morphology, chemical functional groups, whiteness index, and crystallinity. Fourier-transform infrared spectroscopy (FTIR) and chemical composition results showed that alkali treatment (NaOH) and bleaching (3%, 5%, and 7% of sodium hypochlorite, NaClO) were effective in the removal of lignin and hemicellulose. The variation of sodium hypochlorite concentration affected physical and structural characteristics of the NCC produced, which exhibited a rod-shaped structure with diameters ranging from 17 to 49 nm. These observations provide insight into the potential utilization of L. leucocephala as raw material for preparing nanocellulose, which may address problems of the underutilized mature pods.

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Electronic structure and properties of alkoxymethylenemalonic acid derivatives

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19791423 ◽

1979 ◽

Vol 44 (5) ◽

pp. 1423-1433 ◽

Cited By ~ 6

Author(s):

Dušan Ilavský ◽

Jiří Krechl ◽

Petr Trška ◽

Josef Kuthan

Keyword(s):

Electronic Structure ◽

Quantum Chemical ◽

Chemical Reactivity ◽

Dipole Moments ◽

Structure And Properties ◽

Geometrical Isomers ◽

H Nmr ◽

Geometrical Isomerism ◽

Pmr Spectra ◽

Insight Into

Six compounds RO(H)C=C(X)CN with R = CH3 or C2H5 and X = CO2CH3, CO2C2H5 or CN are characterized by some spectral data (IR, UV, 1H NMR - solvent effect). The PMR spectra did not confirm the presence of two geometrical isomers. Employing the quantum chemical calculations of the substance with R = CH3 and X = CO2CH3 based on EHT, PPP, HMO and CNDO/2, the geometrical isomerism is discussed in relation to the experimental dipole moments. The HMO indices of chemical reactivity agree with our present synthetic insight into nucleophilic substitution of the derivatives under study.

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