In:
Angewandte Chemie, Wiley, Vol. 133, No. 28 ( 2021-07-05), p. 15580-15586
Abstract:
Clarifying interfacial electronic effects on molecular adsorption is significant in many chemical and biochemical processes. Here, we used STM breaking junction and shell‐isolated nanoparticle‐enhanced Raman spectroscopy to probe electron transport and adsorption geometries of 4,4′‐bipyridine (4,4′‐BPY) at Au(111). Modifying the surface with 1‐butyl‐3‐methylimidazolium cation‐containing ionic liquids (ILs) decreases surface electron density and stabilizes a vertical orientation of pyridine through nitrogen atom σ‐bond interactions, resulting in uniform adsorption configurations for forming molecular junctions. Modulation from vertical, tilted, to flat, is achieved on adding water to ILs, leading to a new peak ascribed to CC stretching of adsorbed pyridyl ring and 316 % modulation of single‐molecule conductance. The dihedral angle between adsorbed pyridyl ring and surface decreases with increasing surface electronic density, enhancing electron donation from surface to pyridyl ring.
Type of Medium:
Online Resource
ISSN:
0044-8249
,
1521-3757
DOI:
10.1002/ange.v133.28
DOI:
10.1002/ange.202102587
Language:
English
Publisher:
Wiley
Publication Date:
2021
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514305-6
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505872-7
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1479266-7
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