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Direct Visualization of the Two-step Nucleation Model by Fluorescence Color Changes during Evaporative
Fuyuki Ito1, Yukino Suzuki1, Jun-ichi Fujimori1
1Department of Chemistry, Institute of Education, Shinshu University, 6-ro Nishinagano, Nagano 380-8544, Japan.
Scientific Reports
|March 9, 2016
Summary
This study visualizes the two-step nucleation model in organic crystallization using mechanofluorochromic molecules. Researchers observed transitional emission from amorphous clusters, confirming a key step in crystal formation.
Area of Science:
- Materials Science
- Chemical Physics
- Crystallography
Background:
- Classical nucleation theory (CNT) describes crystal formation but has limitations.
- The two-step nucleation model proposes an intermediate amorphous cluster phase.
- Direct visualization of this intermediate phase in organic crystallization remains challenging.
Purpose of the Study:
- To provide direct visualization of the two-step nucleation model in organic molecular crystallization.
- To investigate the role of amorphous clusters in the crystallization process.
- To utilize mechanofluorochromism as a probe for nucleation events.
Main Methods:
- Evaporative crystallization of a dibenzoylmethane boron complex was employed.
- Mechanofluorochromism of the complex was used to monitor crystallization via fluorescence changes.
- The influence of complex concentration in a polymer matrix on fluorescence was studied.
Main Results:
- Transitional fluorescence emission was detected from amorphous clusters preceding crystallization.
- The fluorescence changes correlated with the dispersion concentration of the complex.
- This observation provides direct evidence for the amorphous cluster intermediate.
Conclusions:
- The study successfully demonstrates the two-step nucleation model for organic crystallization.
- Mechanofluorochromism offers a novel method for probing nucleation dynamics.
- The findings support the existence of an amorphous cluster state in crystal nuclei formation.
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