Peptide-based biomimetic catalysts are promising materials
for
efficient catalytic activity in various biochemical transformations.
However, their lack of operational stability and fragile nature in
non-aqueous media limit their practical applications. In this study,
we have developed a cladding technique to stabilize biomimetic catalysts
within porous covalent organic framework (COF) scaffolds. This methodology
allows for the homogeneous distribution of peptide nanotubes inside
the COF (TpAzo and TpDPP) backbone, creating strong noncovalent interactions
that prevent leaching. We synthesized two different peptide-amphiphiles,
C10FFVK and C10FFVR, with lysine (K) and arginine
(R) at the C-termini, respectively, which formed nanotubular morphologies.
The C10FFVK peptide-amphiphile nanotubes exhibit enzyme-like
behavior and efficiently catalyze C–C bond cleavage in a buffer
medium (pH 7.5). We produced nanotubular structures of TpAzo–C10FFVK and TpDPP–C10FFVK through COF cladding
by using interfacial crystallization (IC). The peptide nanotubes encased
in the COF catalyze C–C bond cleavage in a buffer medium as
well as in different organic solvents (such as acetonitrile, acetone,
and dichloromethane). The TpAzo–C10FFVK catalyst,
being heterogeneous, is easily recoverable, enabling the reaction
to be performed for multiple cycles. Additionally, the synthesis of
TpAzo–C10FFVK thin films facilitates catalysis in
flow. As control, we synthesized another peptide-amphiphile, C10FFVR, which also forms tubular assemblies. By depositing
TpAzo COF crystallites on C10FFVR nanotubes through IC,
we produced TpAzo–C10FFVR nanotubular structures
that expectedly did not show catalysis, suggesting the critical role
of the lysines in the TpAzo–C10FFVK.