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Published on: November 21, 2013
Anchoring-group-controlled self-assembly and charge transport in antiaromatic molecular systems
Shintaro Fujii1, Koshiro Isono2, Kazuki Nabeyama1
1Department of Chemistry, School of Science, Institute of Science Tokyo, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan. fujii.s.e8cc@m.isct.ac.jp.
Nanoscale
|May 22, 2026
Summary
Chemically stable antiaromatic molecules show promise for charge transport. Anchoring groups control surface assembly and conductance, crucial for molecular electronics design.
Area of Science:
- Materials Science
- Chemistry
- Physics
Background:
- Antiaromatic π-systems (4n electrons) offer potential for enhanced charge transport due to narrow frontier orbital gaps.
- Experimental studies of antiaromatic systems at the single-molecule level are limited by their instability.
- Nickel(II) norcorrole (Ni(nor)) provides a stable antiaromatic platform for investigation.
Purpose of the Study:
- To investigate the impact of anchoring groups on the surface assembly and charge transport properties of a stable antiaromatic Ni(II) norcorrole.
- To explore the relationship between anchoring chemistry, metal-molecule coupling, and orbital alignment in molecular junctions.
- To elucidate the role of antiaromaticity versus anchoring group chemistry in determining molecular conductance.
Main Methods:
- Utilized scanning tunnelling microscopy (STM) to image surface assemblies.
- Employed single-molecule break-junction (BJ) measurements to quantify charge transport.
- Synthesized Ni(II) norcorrole functionalized with thiol, pyridyl, and carboxyl anchoring groups.
Main Results:
- STM revealed distinct surface assemblies based on anchoring groups: thiols formed upright monolayers, carboxyls formed 1D chains via hydrogen bonding, and pyridyls showed no ordered assembly on Au(111).
- Charge transport efficiency was systematically modulated by anchoring-dependent variations in metal-molecule coupling and orbital alignment.
- Antiaromatic Ni(II) norcorrole provided high intrinsic conductance, while anchoring groups dictated conductance modulation and assembly behavior.
Conclusions:
- Anchoring-group chemistry is the primary design parameter for controlling metal-molecule coupling, surface assembly, and charge transport in molecular junctions.
- Antiaromaticity establishes a favorable electronic baseline for high conductance, but anchoring groups are key drivers of specific trends and assembly.
- This work underscores the critical importance of anchoring chemistry for designing functional molecular devices.
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