Significant Chiral Signal Amplification of Langmuir Monolayers Probed by Second Harmonic Generation.
With the development of the nonlinear optical technique such as SHG (second harmonic generation), the in situ measurements of the chirality in the monolayers at the air/water interface have become possible. However, when performing the SHG measurement of the chirality in a monolayer, it is still a great challenge to obtain the chiral signals with a good S/N (signal-to-noise) ratio. In this Letter, interfacial assemblies with induced supramolecular chirality were used to amplify the weak chiral SHG signals from the monolayers at the air/water interface. Tetrakis(4-sulfonatophenyl) porphyrin (TPPS) J aggregates were used as the subphase, and when chiral amphiphilic molecules were spread on it, chiral domains of the amphiphile/TPPS J aggregates were formed and then significantly amplified chiral signals that otherwise could not be detected. Moreover, the sign of the DCE (degree of chiral excess) changed with the chirality of the amphiphilic molecules, thus providing a possible way to obtain the absolute chiral information in situ in the monolayers.
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Kai
K
Lv
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Lu
L
Lin
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Xiaoyu
X
Wang
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Li
L
Zhang
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Yuan
Y
Guo
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Zhou
Z
Lu
Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Colloid, Interface and Thermodynamics, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Minghua
M
Liu
D011166:Porphyrins / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013499:Surface Properties
D011166:Porphyrins
SHG signals; TPPS J aggregates; air/water interface; nonlinear optical technique; supramolecular chirality