1 research outputs found
Recyclable l‑Proline Functional Nanoreactors with Temperature-Tuned Activity Based on Core–Shell Nanogels
Recyclable core–shell (CS)
nanogels based on l-proline-containing
hydrophobic cores with a thermoresponsive polyÂ(<i>N</i>-isopropylacrylamide)
(PNIPAM) shell have been synthesized via a seeded precipitation polymerization
process. Dynamic light scattering (DLS) and transmission electron
microscopy (TEM) were used to verify the successful addition of the
shell and investigate the thermoresponsive properties of the nanostructures.
The catalytic activity of the nanogels was assessed in a model asymmetric
aldol reaction, where an enhancement was observed with increasing
temperature, attributed to the hydrophobic nature of the PNIPAM shell.
However, when a nanogel was synthesized with core–shell morphology
based on a gradient of cross-linking density in the corona (GS), a
dramatic drop in activity was observed at elevated temperatures: the
collapse of the outer, lightly cross-linked, “corona”
polymer chains appears to block access to the catalytic core. High
activity and enantioselectivity were maintained in a number of recovery
and reuse cycles, highlighting the recycling potential of these catalytic
nanostructures