Issue 17, 2011
From the journal:

Physical Chemistry Chemical Physics

Fluorescence studies on phenylene moieties embedded in a framework of periodic mesoporous organosilica†

Tadashi Okada,*a   Ken-ichi Yamanaka,bc   Yoshiharu Hirose,b   Yasutomo Goto,bc   Takao Tanibc  and  Shinji Inagaki*bc  

* Corresponding authors

a Toyota Physical & Chemical Research Institute, Nagakute, Aichi 480-1192, Japan
E-mail: riken-okada@mosk.tytlabs.co.jp

b Toyota Central R&D Labs., Inc., Nagakute, Aichi 480-1192, Japan
E-mail: inagaki@mosk.tytlabs.co.jp

c Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan

Abstract

The excited state characteristics of phenylene (Ph)-bridged periodic mesoporous organosilica (PMO) powders with crystal-like and amorphous wall structures are investigated. Crystal-like Ph–PMO has a molecular ordering of the bridging organic moieties with intervals of 0.76 and 0.44 nm parallel and perpendicular to the mesochannel direction, respectively, whereas amorphous Ph–PMO has no molecular-level periodicity in the wall. Fluorescence from the exciton and excimer of the Ph moieties and the defect center in the silicate network were detected at room temperature, but fluorescence from the excimer and the defect center were not detected at 77 K for crystal-like Ph–PMO dispersed in a methanol/ethanol mixed solvent. The decay curve of the exciton fluorescence of crystal-like Ph–PMO at room temperature was analyzed successfully using a one-dimensional diffusion model quenched by the defect center and the excimer site. The results were discussed in comparison with those for the crystal-like biphenylene-bridged PMO reported in the preceding paper (Yamanaka et al., Phys. Chem. Chem. Phys., 2010, 12, 11688–11696). The existence of excited states with various conformations including ground state dimers or aggregates of the Ph moieties was suggested for amorphous Ph–PMO. It was clearly apparent that the differences in the excited state dynamics reflected the differences in the molecular-level structure in the wall.

Graphical abstract: Fluorescence studies on phenylene moieties embedded in a framework of periodic mesoporous organosilica

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Article information

DOI
https://doi.org/10.1039/C0CP02714F
Article type
Paper
Submitted
30 Nov 2010
Accepted
28 Feb 2011
First published
24 Mar 2011

Phys. Chem. Chem. Phys., 2011,13, 7961-7967

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Fluorescence studies on phenylene moieties embedded in a framework of periodic mesoporous organosilica

T. Okada, K. Yamanaka, Y. Hirose, Y. Goto, T. Tani and S. Inagaki, Phys. Chem. Chem. Phys., 2011, 13, 7961 DOI: 10.1039/C0CP02714F

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