Photoinduced Electron Transfer within Supramolecular Donor–Acceptor Peptide Nanostructures under Aqueous Conditions

Abstract

We report the synthesis, self-assembly, and electron transfer capabilities of peptide-based electron donor-acceptor molecules and supramolecular nanostructures. These modified peptides contain π-conjugated oligothiophene electron donor cores that are peripherally substituted with naphthalene diimide electron acceptors installed via imidation of site-specific lysine residues. These molecules self-assemble into one-dimensional nanostructures in aqueous media, as shown through steady-state absorption, photoluminescence, and circular dichroism spectra, as well as transmission electron microscopy. Excitation of the oligothiophene donor moieties results in electron transfer to the acceptor units, ultimately creating polar, charge-separated states that persist for over a nanosecond as observed with transient absorption spectroscopy. This study demonstrates how transient electric fields can be engineered into aqueous nanomaterials of biomedical relevance through external, temporally controlled photonic inputs.

Macroscale Biomolecular Electronics and Ionics

“…Alternative approach of using peptides for the formation of electron conducting materials was developed by the group of Tovar who designed a unique form of peptide amphiphiles, where short peptide sequences (3–5 amino acids) were attached to the two ends of an oligo‐phenylenevinylene or an oligothiophene segment ( Figure a) . In this configuration, the peptides direct the self‐assembly of the molecule to a 1D fibril composed of β‐sheet structure, and resulting in the stacking of the oligo‐phenylenevinylene or oligothiophene units to form a π‐conjugated structure (Figure b).…”

DLPNO-CCSD(T) scaled methods for the accurate treatment of large supramolecular complexes

“…In the field of materials science, for instance, different electron‐acceptor nanoforms of carbon, namely fullerenes, carbon nanotubes, and graphene, have been successfully combined by means of NCIs with electron‐donor systems to form donor–acceptor (D–A) supramolecular complexes . Experimental studies on these D–A supramolecular complexes are of great relevance to gain insight into the fundamental and omnipresent photoinduced electron‐transfer process, which is required, for example, in organic photovoltaic applications …”

“…[2][3][4][5][6][7][8][9] Experimental studies on these D-A supramolecular complexes are of great relevance to gain insight into the fundamental and omnipresent photoinduced electron-transfer process, which is required, for example, in organic photovoltaic applications. [10][11][12][13] If we turn our attention to fullerenes, C 60 and its derivatives, a large number of p-conjugated electron-donating systems are able to host the buckyball through p-p intermolecular interactions, [5,7,8,[14][15][16] a particular kind of NCIs. Among the different donor moieties employed, the truxene-tetrathiafulvalene (truxTTF) system ( Fig.…”

Tuning Optoelectronic and Chiroptic Properties of Peptide‐Based Materials by Controlling the Pathway Complexity

“…Thus, controlling the pathway complexity anddetermining the specific parameters to activate and trap theses tates is ac onceptual and technologically relevant issue, introducing it as an ew variable in the aforementioned classical binomial. [5] Furthermore, their final function and applications are dramatically affected by these parameters. [4] However,c ontrolling the morphology and electrochemical and photophysical properties of the formed ensembles still remains an outstanding challenge.…”

“…[4] However,c ontrolling the morphology and electrochemical and photophysical properties of the formed ensembles still remains an outstanding challenge. [5] Furthermore, their final function and applications are dramatically affected by these parameters. Recent investigations have been focused in this direction, for which amino acid mutation, [6] enhancement of the intermolecular p-p interactions betweena romatic units, [7] or solvent-controlled assembly [8] have been used to modify the properties of the functional supramolecular materials.…”