Quantum Interference and Aromaticity Control in Triazine-Based Molecular Junctions: A Combined Green's Function and...

Area of Science:

• Molecular electronics
• Quantum transport phenomena
• Single-molecule studies

Background:

• Charge transport at the single-molecule level is dictated by molecular structure, connectivity, and electronic delocalization.
• Graphitic carbon nitride motifs serve as inspiration for novel molecular electronic components.

Purpose of the Study:

• To computationally investigate electron transport through triazine-based molecular junctions.
• To analyze quantum interference effects and their dependence on molecular architecture.
• To understand the relationship between electronic delocalization, aromaticity, and molecular conductance.

Main Methods:

• Utilized a bottom-up approach to model triazine monomers, heptazine, and tri-heptazine scaffolds.
• Employed the nonequilibrium Green's function formalism combined with density functional theory (DFT).
• Analyzed transmission spectra, local transmission pathways, and quantum interference patterns.

Main Results:

• Nitrogen-rich conjugated frameworks exhibit diverse quantum interference patterns (constructive, destructive, shifted destructive).
• Interference features are sensitive to molecular connectivity and substitution patterns.
• Substituent effects modulate molecular conductance in a topology-dependent manner, correlating with electronic delocalization and aromaticity.

Conclusions:

• Molecular connectivity and substituents significantly influence quantum interference and conductance in triazine-based systems.
• Aromaticity descriptors correlate with transmission behavior, highlighting the role of electronic delocalization.
• Complex interplay between transmission pathways in extended architectures leads to non-trivial aromaticity-conductance relationships.