动态共价化学桥的电荷传输《Nano Letters》

Charge Transport Across Dynamic Covalent Chemical Bridges

Zelin Miao, Timothy Quainoo, Thomas M. Czyszczon-Burton, Nils Rotthowe, Joseph M. Parr, Zhen-Fei Liu*, and Michael S. Inkpen*

Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States

Nano Lett. 2022, XXXX, XXX, XXX-XXX

Publication Date: October 10, 2022

https://doi.org/10.1021/acs.nanolett.2c03288

LETTER

Abstract

Relationships between chemical structure and conductivity in ordered polymers (OPs) are difficult to probe using bulk samples. We propose that conductance measurements of appropriate molecular-scale models can reveal trends in electronic coupling(s) between repeat units that may help inform OP design. Here, we apply the scanning tunneling microscope-based break-junction (STM-BJ) method to study transport through single-molecules comprising OP-relevant imine, imidazole, diazaborole, and boronate ester dynamic covalent chemical bridges. Notably, solution-stable boron-based compounds dissociate in situ unless measured under a rigorously inert glovebox atmosphere. We find that junction conductance negatively correlates with the electronegativity difference between bridge atoms, and corroborative first-principles calculations further reveal a different nodal structure in the transmission eigenchannels of boronate ester junctions. This work reaffirms expectations that highly polarized bridge motifs represent poor choices for the construction of OPs with high through-bond conductivity and underscores the utility of glovebox STM-BJ instrumentation for studies of air-sensitive materials.

SUBJECTS:

• Atmospheric chemistry,

• Electrical conductivity,

• Molecular structure,

• Molecules,

• Organic compounds