On the Search of a Silver Bullet for the Preparation of Bioinspired Molecular Electrets with Propensity to Transfer Holes at High Potentials.

James Bennett Derr,Valentine Ivanov Vullev,John Anthony Clark,Katarzyna Rybicka-Jasińska,Eli Misael Espinoza,Mimi Karen Billones,Maryann Morales

doi:10.3390/biom11030429

James Bennett Derr, Valentine Ivanov Vullev + Show 5 more

Open Access

https://doi.org/10.3390/biom11030429

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Journal: Biomolecules	Publication Date: Mar 15, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: University of California, Riverside

Abstract

Biological structure-function relationships offer incomparable paradigms for charge-transfer (CT) science and its implementation in solar-energy engineering, organic electronics, and photonics. Electrets are systems with co-directionally oriented electric dopes with immense importance for CT science, and bioinspired molecular electrets are polyamides of anthranilic-acid derivatives with designs originating from natural biomolecular motifs. This publication focuses on the synthesis of molecular electrets with ether substituents. As important as ether electret residues are for transferring holes under relatively high potentials, the synthesis of their precursors presents formidable challenges. Each residue in the molecular electrets is introduced as its 2-nitrobenzoic acid (NBA) derivative. Hence, robust and scalable synthesis of ether derivatives of NBA is essential for making such hole-transfer molecular electrets. Purdie-Irvine alkylation, using silver oxide, produces with 90% yield the esters of the NBA building block for iso-butyl ether electrets. It warrants additional ester hydrolysis for obtaining the desired NBA precursor. Conversely, Williamson etherification selectively produces the same free-acid ether derivative in one-pot reaction, but a 40% yield. The high yields of Purdie-Irvine alkylation and the selectivity of the Williamson etherification provide important guidelines for synthesizing building blocks for bioinspired molecular electrets and a wide range of other complex ether conjugates.

Highlights

IntroductionA principal task in this line of research was making the Aa bioinspired molecules [28,29], which is the focus of this publication
To take the field out of this confinement, we developed the concept for charge transfer (CT) bioinspired molecular electrets (Figure 1) [17,18,19,20,21,22,23,24,25,26,27,28,29]
To build the Aa strands from the C- to the N-terminus, we introduced each of the amino acids as its 2-nitrobenzoic acid (NBA) analogues (Figure 2b)

Summary

Introduction

A principal task in this line of research was making the Aa bioinspired molecules [28,29], which is the focus of this publication While they are polypeptides of aromatic β-amino acids, none of the strategies for chemical or biochemical synthesis of biological and biomimetic peptides works for making Aa conjugates (Figure 2a) [29]. With ether 3 in hand, we demonstrate the synthesis of electret oligomers that revealed substantial differences in the reactivities for coupling different residues together These findings about PIA and on building the oligomers provide key guidelines for the design of the synthesis of bioinspired molecular electrets, and for a wide range of ether derivatives

Choice of Substrates

Synthesis Design

Testing Beyond Ag2 O

Box-Containing Oligomers

Conclusions