Achievement of stereoselective up-conversion processes using a chiral donor/acceptor pair in the presence of synthetic saponite

1. Up-conversion is achieved for a colloidal dispersion of synthetic saponite.
2. Ru(II) complex and DPA were used as a donor/acceptor pair for triplet-triplet annihilation.
3. Synthetic saponite showed an effect of decreasing the minimum concentration of DPA required for up-conversion.
4. Stereoselectivity was observed between diastereomeric pairs in the efficiency of up-conversion.

The purposes of the present work are: (i) to achieve the up-conversion of photon energy in the presence of colloidal clay; (ii) to introduce molecular recognition in up-conversion to be utilized for molecular chiral sensing.
The up-conversion (UC) of photon energy was attempted for a system of colloidal clay dispersion through the mechanism of triplet-triplet annihilation (TTA). Tris（1,10-phenanthroline）ruthenium (II) ([Ru(phen)₃]²⁺) and 9,10-diphenylanthracne (DPA) were used as donor and acceptor, respectively. A clay mineral used was synthetic saponite. The medium was 1:1:0.1 (v/v) methanol/dichloromethane/water. Δ-[Ru(phen)₃]²⁺ was adsorbed by SAP to 26% CEC (cation exchange capacity). The dispersion was irradiated by a laser light (0.5 mW) at 450 nm in the presence of DPA. The emission, which peaked around 430 nm, was observed under air. This indicates that the Ru(II) complex adsorbed by colloidal clay acted as a donor to achieve UC. Stereoselectivity was observed when a chiral donor/acceptor pair was employed. The results implied that the fixation of a donor molecule on a clay surface resulted in enhancing chiral selectivity during the courses of donor/acceptor energy transfer and/or TTA of excited acceptors. The results open up the possibility of developing chiral sensing on the basis of the up-conversion of colloidal clay systems.

Reference URL: https://www.sciencedirect.com/science/article/abs/pii/S0169131724001455

Bibliographic Information

Up-conversion of Photon Energy in Colloidal Clay Systems
Akihiko Yamagishi, Kenji Tamura＊, Shohei Yamamoto, Fumi Sato, Jun Yoshida and Hisako Sato＊
Apply Clay Sci. 2024, 255, 107397

Fundings

• Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number JP17H03044, JP20K21090, JP22H02033

Media

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  Construction of an Up-conversion of a photon energy system in the presence of colloidally dispersed synthetic saponite.

  Stereoselective up-conversion with a chiral donor/acceptor pair in the presence of colloidally dispersed synthetic saponite.

  credit : Hisako Sato
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