Fluorinated aminoanthranilamides: non-native amino acids for bringing proteomic approaches to charge-transfer systems

Abstract

The ability to control charge transfer at molecular and nanometer scales represents the ultimate level of electronic mastery, and its impacts cannot be overstated. As electrostatic analogues of magnets, electrets possess ordered electric dipoles that present key paradigms for directing transduction of electrons and holes. Herein we describe the design and development of fluorinated aminoanthranilamides, derivatives of non-native aromatic beta-amino acids, as building blocks for hole-transfer molecular electrets. A highly regio-selective nucleophilic aromatic substitution of difluorinated nitrobenzoic acid provides the underpinnings for an array of unprecedented anthranilamide structures. Spin density distribution and electrochemical analyses reveal that fluorine induces about 200 mV positive shifts in reduction potentials without compromising the stability of the oxidized residues, making them invaluable building blocks for hole-transfer systems. These findings open unexplored routes to novel amino-acid structures, setting a foundation for bringing principles of proteomics to designs of charge-transfer systems.

Covalently Linked Bis(Amido‐Corroles): Inter‐ and Intramolecular Hydrogen‐Bond‐Driven Supramolecular Assembly

“…These structures include helices, [13] zig-zags, [14] antiparallel b-strands, [15] tapes, [16] macrocycles, [17] cryptands, [18] capsules, [19] Janus-dendrimers, [20] and molecular electrets. [21] Clearly,this ability has been utilized by naturet oformthree-dimensional peptide and protein secondary structures. [22] Although the propensity of -NHCO-groups to form strong hydrogen bondsh as been known for al ong time, chemists continue to reinvent it by revealing new typeo fs tructures every once in aw hile.…”

Bioinspired approach toward molecular electrets: synthetic proteome for materials

“…For chemical stability, however, the spin-density distribution of the radical cation of a residue, Aa˙+, which closely resembles the distribution of the HOMO of the ground-state electroneutral species, Aa, should not extend over its C-terminal amide (Fig. 4) [32,33]. Therefore, a covalent attachment via the N-terminal amide of such Aa moiety provides a stronger electronic coupling for hole injection than attachment via the C-terminal amide.…”

“…1c), with N-and C-termini capped as alkylamides (black -excess spin up, i.e. radical cation; and white, excess spin down) [32,33,35]. The residues are grouped according to the reversibility of their electrochemical oxidation.…”

“…Aaa, i.e. N,N′-(2-(heptan-4-ylcarbamoyl)-1,4-phenylene)bis(2-propylpentanamide), was prepared in three steps (Scheme 1), employing adopted procedures for making anthranilamide derivatives [31,33]. The wavelength values of the two maxima of the absorption spectra (around 315 and 270 nm) and the maxima of the fluorescence spectra (at around 390 nm) were obtained from Gaussian fits of the tip of the spectral bands (Fig.…”

“…We focus on electron-donating substituents (Fig. 1c,d) producing residues for HT molecular electrets [31][32][33]. One of the distal sites, R 2 ( Fig.…”