Topic
Amine binding
About: Amine binding is a research topic. Over the lifetime, 87 publications have been published within this topic receiving 3255 citations.
Papers published on a yearly basis
Papers
TL;DR: In this paper, the authors measured the conductance of amine-terminated molecules by breaking Au point contacts in a molecular solution at room temperature, and they found that the variability of the observed conductance for the diamine molecule−Au junctions is much less than the variability for diisonitrile− and dithiol−AU junctions.
Abstract: We measure the conductance of amine-terminated molecules by breaking Au point contacts in a molecular solution at room temperature. We find that the variability of the observed conductance for the diamine molecule−Au junctions is much less than the variability for diisonitrile− and dithiol−Au junctions. This narrow distribution enables unambiguous conductance measurements of single molecules. For an alkane diamine series with 2−8 carbon atoms in the hydrocarbon chain, our results show a systematic trend in the conductance from which we extract a tunneling decay constant of 0.91 ± 0.03 per methylene group. We hypothesize that the diamine link binds preferentially to undercoordinated Au atoms in the junction. This is supported by density functional theory-based calculations that show the amine binding to a gold adatom with sufficient angular flexibility for easy junction formation but well-defined electronic coupling of the N lone pair to the Au. Therefore, the amine linkage leads to well-defined conductanc...
858 citations
TL;DR: The results clearly demonstrate that Mn2+:ZnO ferromagnetism is critically sensitive to defects other than the magnetic dopants themselves, offering some insight into the diversity of experimental observations reported previously for this material.
Abstract: We report the discovery that high-TC ferromagnetism in manganese-doped ZnO (Mn2+:ZnO) can be activated by amine binding and calcination. The activation of ferromagnetism is attributed to the incorporation of uncompensated p-type dopants into the ZnO lattice upon amine calcination, a process that has substantial precedence in the literature surrounding p-type ZnO. The experimental observations are consistent with a microscopic mechanism involving formation of bound magnetic polarons upon introduction of p-type dopants into Mn2+:ZnO. These results clearly demonstrate that Mn2+:ZnO ferromagnetism is critically sensitive to defects other than the magnetic dopants themselves, offering some insight into the diversity of experimental observations reported previously for this material.
183 citations
TL;DR: Higher CO2 capacity and uptake rate is demonstrated for PEI supported in a hydrophobically modified silica, which exhibits repulsive interactions with the PEI, freeing up binding sites.
Abstract: Composites of poly(ethylenimine) (PEI) and mesoporous silica are effective, reversible adsorbents for CO2, both from flue gas and in direct air-capture applications. The morphology of the PEI within the silica can strongly impact the overall carbon capture efficiency and rate of saturation. Here, we directly probe the spatial distribution of the supported polymer through small-angle neutron scattering (SANS). Combined with textural characterization from physisorption analysis, the data indicate that PEI first forms a thin conformal coating on the pore walls, but all additional polymer aggregates into plug(s) that grow along the pore axis. This model is consistent with observed trends in amine-efficiency (CO2/N binding ratio) and pore size distributions, and points to a trade-off between achieving high chemical accessibility of the amine binding sites, which are inaccessible when they strongly interact with the silica, and high accessibility for mass transport, which can be hampered by diffusion through PE...
155 citations
TL;DR: A mechanism of action, derived from that of thermolysin, is proposed for these aminopeptidases, which explains the importance of E350 in transition state formation, rather than in the Michaelis complex.
Abstract: The molecular components ensuring the strict exopeptidase action of aminopeptidase N (APN) and related zinc aminopeptidases of the M1 family have not yet been clearly established. The specific recognition of the N-terminal amino acid of the substrates by the enzymes has been proposed to involve either the complexation of the free amino group by the catalytic zinc ion or an interaction with an anionic binding site, which could be constituted by an aspartate or glutamate residue. To investigate the existence of such an ionic binding site, site-directed mutagenesis experiments have been performed on acidic residues of pig APN. Given that aminopeptidases of the M1 family are likely to have a common mechanism of action, only strictly conserved residues were mutated. As compared to the wild-type enzyme, the mutation D220E led only to slight modifications in the kinetic parameters of the enzyme and in the Ki values of various inhibitors, indicating that this residue is not critically involved in the hydrolytic m...
109 citations
TL;DR: The results suggest that the catalytic activity can be enhanced by employing a more electron-deficient ligand backbone and the overall reaction rate is limited either by amide exchange or alkene insertion, as supported by reaction kinetics, kinetic isotope effects, and isotopic labeling studies.
Abstract: The intermolecular hydroaminoalkylation of unactivated alkenes and vinyl arenes with secondary amines occurs readily in the presence of tantalum and niobium binaphtholate catalysts with high regio- and enantioselectivity (up to 98% ee). Mechanistic studies have been conducted in order to determine the kinetic order of the reaction in all reagents and elucidate the rate- and stereodetermining steps. The effects of substrate steric and electronic properties on the overall reaction rate have been evaluated. The reaction is first order in amine and the catalyst, while exhibiting saturation in alkene at high alkene concentration. Unproductive reaction events including reversible amine binding and arene C–H activation have been observed. The formation of the metallaaziridine is a fast reversible nondissociative process and the overall reaction rate is limited either by amide exchange or alkene insertion, as supported by reaction kinetics, kinetic isotope effects, and isotopic labeling studies. These results sug...
107 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 3 |
| 2019 | 2 |
| 2018 | 3 |
| 2017 | 2 |
| 2016 | 4 |
| 2015 | 4 |