28 Feb 12:34
by Eric Koesema,
Animesh Roy,
Nicholas G. Paciaroni,
Carlos Coito,
Michal Tokmina-Roszyk,
Thomas James Kodadek
The discovery of ligands for the “undruggable proteome” is likely to require the development of new chemical matter with a greater “molecular wingspan” than traditional Lipinski-compliant small molecules. A DNA-encoded library (DEL) of non-peptidic thioether macrocycles has been constructed and screened for high affinity protein ligands to a model protein, SA.
Abstract
There is considerable interest in the development of libraries of non-peptidic macrocycles as a source of ligands for difficult targets. We report here the solid-phase synthesis of a DNA-encoded library of several hundred thousand thioether-linked macrocycles. The library was designed to be highly diverse with respect to backbone scaffold diversity and to minimize the number of amide N−H bonds, which compromise cell permeability. The utility of the library as a source of protein ligands is demonstrated through the isolation of compounds that bind Streptavidin, a model target, with high affinity.
03 Jun 07:28
by Sabbir A. Khan,
Lukas Stampfer,
Timo Mutas,
Jung‐Hyun Kang,
Peter Krogstrup,
Thomas S. Jespersen
Methods for growth of high-quality InSb nanocrosses by molecular beam epitaxy are developed, and electrical measurements at low temperature demonstrate ballistic transport in the individual nanowire terminals and through the junction.
Abstract
By studying the time-dependent axial and radial growth of InSb nanowires (NWs), the conditions for the synthesis of single-crystalline InSb nanocrosses (NCs) by molecular beam epitaxy are mapped. Low-temperature electrical measurements of InSb NC devices with local gate control on individual terminals exhibit quantized conductance and are used to probe the spatial distribution of the conducting channels. Tuning to a situation where the NC junction is connected by few-channel quantum point contacts in the connecting NW terminals, it is shown that transport through the junction is ballistic except close to pinch-off. Combined with a new concept for shadow-epitaxy of patterned superconductors on NCs, the structures reported here show promise for the realization of non-trivial topological states in multi-terminal Josephson junctions.
24 Dec 10:51
by Amare Aregahegn Dubale,
Yuanyuan Zheng,
Honglei Wang,
René Hübner,
Yi Li,
Jing Yang,
Jiangwei Zhang,
Navpreet Kaur Sethi,
Lanqi He,
Zhikun Zheng,
Wei Liu
Bismuth doping reduces charge‐transfer resistance, creates a strained surface, and optimizes the d‐band center of porous Ni
x
Bi
y
aerogels. The optimum benefits of the amorphous structure and abundant superficial oxygenated species are realized in a Ni97Bi3 aerogel, which demonstrates unprecedented electrocatalytic performance in methanol oxidation with both high activity and durability.
Abstract
Low‐cost, non‐noble‐metal electrocatalysts are required for direct methanol fuel cells, but their development has been hindered by limited activity, high onset potential, low conductivity, and poor durability. A surface electronic structure tuning strategy is presented, which involves doping of a foreign oxophilic post‐transition metal onto transition metal aerogels to achieve a non‐noble‐metal aerogel Ni97Bi3 with unprecedented electrocatalytic activity and durability in methanol oxidation. Trace amounts of Bi are atomically dispersed on the surface of the Ni97Bi3 aerogel, which leads to an optimum shift of the d‐band center of Ni, large compressive strain of Bi, and greatly increased conductivity of the aerogel. The electrocatalyst is endowed with abundant active sites, efficient electron and mass transfer, resistance to CO poisoning, and outstanding performance in methanol oxidation. This work sheds light on the design of high‐performance non‐noble‐metal electrocatalysts.
15 Jun 19:30
by Joshua B. McManus‡, Jeremy D. Griffin‡†, Alexander R. White§, and David A. Nicewicz*
Journal of the American Chemical Society
DOI: 10.1021/jacs.0c04422
