Open AccessSelf-Assembly of Metallo-Supramolecules under Kinetic or Thermodynamic Control: Characterization of Positional Isomers Using Scanning Tunneling Spectroscopy
Author(s) -
Lei Wang,
Bo Song,
Yiming Li,
Lele Gong,
Xin Jiang,
Ming Wang,
Shuai Lu,
XinQi Hao,
Zhaoqiang Xia,
Yuan Zhang,
SawWai Hla,
Xiaopeng Li
Publication year - 2020
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.0c03459
Subject(s) - chemistry , scanning tunneling microscope , kinetic control , self assembly , characterization (materials science) , kinetic energy , spectroscopy , scanning tunneling spectroscopy , substrate (aquarium) , chemical physics , computational chemistry , nanotechnology , organic chemistry , catalysis , materials science , physics , quantum mechanics , oceanography , geology
Coordination-driven self-assembly has been extensively employed to construct a variety of discrete structures as a bottom-up strategy. However, mechanistic understanding regarding whether self-assembly is under kinetic or thermodynamic control is less explored. To date, such mechanistic investigation has been limited to distinct, assembled structures. It still remains a formidable challenge to study the kinetic and thermodynamic behavior of self-assembly systems with multiple assembled isomers due to the lack of characterization methods. Herein, we use a stepwise strategy which combined self-recognition and self-assembly processes to construct giant metallo-supramolecules with 8 positional isomers in solution. With the help of ultrahigh-vacuum, low-temperature scanning tunneling microscopy and scanning tunneling spectroscopy, we were able to unambiguously differentiate 14 isomers on the substrate which correspond to 8 isomers in solution. Through measurement of 162 structures, the experimental probability of each isomer was obtained and compared with the theoretical probability. Such a comparison along with density functional theory (DFT) calculation suggested that although both kinetic and thermodynamic control existed in this self-assembly, the increased experimental probabilities of isomers compared to theoretical probabilities should be attributed to thermodynamic control.