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Updated: Feb 1, 2026

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
Conformational change due to intramolecular hydrophobic interaction leads to large blue-shifted emission from single
Hui Li1, Ting-Zheng Xie, Zihao Liang
1Department of Polymer Science, The University of Akron, Akron, Ohio 44325, USA.
Abstract:
We demonstrate a unique negative solvatochromic emission (NSE) process from a conformational change of a coordination cage in response to solvent composition. The cationic cage contains two tetra-(4-pyridylphenyl)ethylene (TPPE) luminogens on two opposite faces, linked by Pt(PEt3)2 and isophthalate. When the solvent changes from acetone/acetonitrile/methanol to water, the emission of single cages gradually shifts to short wavelength (NSE) with a drastic value of ∼60 nm. Small angle X-ray scattering (SAXS) measurements indicate a molecular conformational change during the process and intramolecular π-π stacking and hydrophobic interaction between the TPPE planes could be the driving forces. As a comparison, a cage with a longer inter-fluorophore distance does not have such strong intramolecular interactions and only shows regular positive solvatochromic emission (PSE) under the same conditions.
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