2 research outputs found
Multimicrometer Noncovalent Monolayer Domains on Layered Materials through Thermally Controlled Langmuir–Schaefer Conversion for Noncovalent 2D Functionalization
As functionalized 2D materials are
incorporated into hybrid materials, ensuring large-area structural
control in noncovalently adsorbed films becomes increasingly important.
Noncovalent functionalization avoids disrupting electronic structure
in 2D materials; however, relatively weak molecular interactions in
such monolayers typically reduce stability toward solution processing
and other common material handling conditions. Here, we find that
controlling substrate temperature during Langmuir–Schaefer
conversion of a standing phase monolayer of diynoic amphiphiles on
water to a horizontally oriented monolayer on a 2D substrate routinely
produces multimicrometer domains, at least an order of magnitude larger
than those typically achieved through drop-casting. Following polymerization,
these highly ordered monolayers retain their structures during vigorous
washing with solvents including water, ethanol, tetrahydrofuran, and
toluene. These findings point to a convenient and broadly applicable
strategy for noncovalent functionalization of 2D materials in applications
that require large-area structural control, for instance, to minimize
desorption at defects during subsequent solution processing
Accelerating Strain-Promoted Azide–Alkyne Cycloaddition Using Micellar Catalysis
Bioorthogonal conjugation reactions
such as strain-promoted azide–alkyne
cycloaddition (SPAAC) have become increasingly popular in recent years,
as they enable site-specific labeling of complex biomolecules. However,
despite a number of improvements to cyclooctyne design, reaction rates
for SPAAC remain significantly lower than those of the related copper-catalyzed
azide–alkyne cycloaddition (CuAAC) reaction. Here we explore
micellar catalysis as a means to increase reaction rate between a
cyclooctyne and hydrophobic azide. We find that anionic and cationic
surfactants provide the most efficient catalysis, with rate enhancements
of up to 179-fold for reaction of benzyl azide with DIBAC cyclooctyne.
Additionally, we find that the presence of surfactant can provide
up to 51-fold selectivity for reaction with a hydrophobic over hydrophilic
azide. A more modest, but still substantial, 11-fold rate enhancement
is observed for micellar catalysis of the reaction between benzyl
azide and a DIBAC-functionalized DNA sequence, demonstrating that
micellar catalysis can be successfully applied to hydrophilic biomolecules.
Together, these results demonstrate that micellar catalysis can provide
higher conjugation yields in reduced time when using hydrophobic SPAAC
reagents