10.1021/acs.nanolett.8b00949.s001
Chunhui Gu
Chunhui
Gu
Chen Hu
Chen
Hu
Ying Wei
Ying
Wei
Dongqing Lin
Dongqing
Lin
Chuancheng Jia
Chuancheng
Jia
Mingzhi Li
Mingzhi
Li
Dingkai Su
Dingkai
Su
Jianxin Guan
Jianxin
Guan
Andong Xia
Andong
Xia
Linghai Xie
Linghai
Xie
Abraham Nitzan
Abraham
Nitzan
Hong Guo
Hong
Guo
Xuefeng Guo
Xuefeng
Guo
Label-Free Dynamic Detection of Single-Molecule Nucleophilic-Substitution
Reactions
American Chemical Society
2018
biophysics investigations
nucleophilic-substitution reaction
single-molecule approach
elucidating time trajectories
9- phenyl -9-fluorenol
bromide species
Label-Free Dynamic Detection
mechanism
single-molecule level
reaction chemistry
equilibrium conditions
non-equilibrated systems
single-molecule dynamics
formation dynamics
chemical reactions
single-molecule junctions
Single-Molecule Nucleophilic-Substitution Reactions
nanogapped graphene electrodes
carbocation intermediates
transformation pathways
2018-06-06 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Label-Free_Dynamic_Detection_of_Single-Molecule_Nucleophilic-Substitution_Reactions/6463106
The
mechanisms of chemical reactions, including the transformation
pathways of the electronic and geometric structures of molecules,
are crucial for comprehending the essence and developing new chemistry.
However, it is extremely difficult to realize at the single-molecule
level. Here, we report a single-molecule approach capable of electrically
probing stochastic fluctuations under equilibrium conditions and elucidating
time trajectories of single species in non-equilibrated systems. Through
molecular engineering, a single molecular wire containing a functional
center of 9-phenyl-9-fluorenol was covalently wired into nanogapped
graphene electrodes to form stable single-molecule junctions. Both
experimental and theoretical studies consistently demonstrate and
interpret the direct measurement of the formation dynamics of individual
carbocation intermediates with a strong solvent dependence in a nucleophilic-substitution
reaction. We also show the kinetic process of competitive transitions
between acetate and bromide species, which is inevitable through a
carbocation intermediate, confirming the classical mechanism. This
unique method creates plenty of opportunities for carrying out single-molecule
dynamics or biophysics investigations in broad fields beyond reaction
chemistry through molecular design and engineering.