Macrocycles that assemble into nanotubes exhibit emergent properties stemming from their low dimensionality, structural regularity, and distinct interior environments. Here, we report a versatile strategy to synthesize diverse nanotube structures in a single, efficient reaction by using a conserved building block bearing a pyridine ring. Imine condensation of a 2,4,6-triphenylpyridine-based diamine with various aromatic
Optical
analysis of reaction parameters such as enantiomeric excess
(ee), diastereomeric excess (de), and yield are becoming increasingly
useful as assays for differing functional groups become available.
These assays typically exploit reversible covalent or noncovalent
assemblies that impart optical signals, commonly circular dichroism
(CD), that are indicative of the stereochemistry and ee at a stereocenter
proximal to the functional group of interest. Very few assays have
been reported that determine ee and de when two stereocenters are
present, and none have targeted two different functional groups that
are vicinal and lack chromophores entirely. Using a CD assay that
targets chiral secondary alcohols, a separate CD assay for chiral
primary amines, a UV–vis assay for de, and a fluorescence assay
for concentration, we demonstrate a work-flow for speciation of the
enantiomers and diastereomers of 2-aminocyclohexanol as a test-bed
analyte. Because of the fact the functional groups are vicinal, we
found that the ee determination at the two stereocenters is influenced
by the adjacent center, and this led us to implement a chemometric
patterning approach, resulting in a 4% absolute error in full speciation
of the four stereoisomers. The procedure presented herein would allow
for the total speciation of around 96 reactions in 27 min using a
high-throughput experimentation routine. While 2-aminocyclohexanol
is used to demonstrate the methods, the general workflow should be
amenable to analysis of other stereoisomers when two stereocenters
are present.
An irreversible, three-component assembly with 2-formylphenylboronic acid, catechol, and N-hydroxylamines was achieved in aqueous media. The boronate ester product was formed with substituted catechols including l-DOPA. Assembly was found to be orthogonal to common biological functional groups and both copper(I)-catalyzed alkyne-azide cycloaddition and aminoether/carbonyl condensations. Boronate ester formation and aminoether condensation were achieved in one pot with a hexameric peptide.
Organic electrochemical transistors (OECTs) are devices with broad potential in bioelectronic sensing, circuits, and neuromorphic hardware. Their unique properties arise from the use of organic mixed ionic/electronic conductors (OMIECs) as the active channel. Typical OMIECs are linear polymers, where defined and controlled microstructure/morphology, and reliable characterization of transport and charging can be elusive. Semiconducting two‐dimensional polymers (2DPs) present a new avenue in OMIEC materials development, enabling electronic transport along with precise control of well‐defined channels ideal for ion transport/intercalation. To this end, a recently reported 2DP, TIIP, is synthesized and patterned at 10 µm resolution as the channel of a transistor. The TIIP films demonstrate textured microstructure and show semiconducting properties with accessible oxidation states. Operating in an aqueous electrolyte, the 2DP‐OECT exhibits a device‐scale hole mobility of 0.05 cm2 V–1 s–1 and a µC* figure of merit of 1.75 F cm–1 V–1 s–1. 2DP OMIECs thus offer new synthetic degrees of freedom to control OECT performance and may enable additional opportunities such as ion selectivity or improved stability through reduced morphological modulation during device operation.
Herein, we report the oligopeptide-catalyzed
site-selective acylation
of partially protected monosaccharides. We identified catalysts that
invert site-selectivity compared to N-methylimidazole,
which was used to determine the intrinsic reactivity, for 4,6-O-protected glucopyranosides (trans-diols)
as well as 4,6-O-protected mannopyranosides (cis-diols). The reaction yields up to 81% of the inherently
unfavored 2-O-acetylated products with selectivities
up to 15:1 using mild reaction conditions. We also determined the
influence of protecting groups on the reaction and demonstrate that
our protocol is suitable for one-pot reactions with multiple consecutive
protection steps.
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