Published on Web 10/18/2006
Photooxidation of Olefins under Oxygen in Platinum(II)
Complex-Loaded Mesoporous Molecular Sieves
Ke Feng,† Ren-Yuan Zhang,‡ Li-Zhu Wu,*,† Bo Tu,‡ Ming-Li Peng,† Li-Ping Zhang,†
Dongyuan Zhao,*,‡ and Chen-Ho Tung†
Contribution from the Laboratory of Supramolecular Photochemistry, Technical Institute of
Physics and Chemistry & Graduate UniVersity, the Chinese Academy of Sciences, Beijing
100080, People’s Republic of China, and Department of Chemistry, Shanghai Key Laboratory of
Molecular Catalysis and InnoVatiVe Materials and AdVanced Materials Laboratory, Fudan
UniVersity, Shanghai 200433, People’s Republic of China
Received July 14, 2006; E-mail: lzwu@mail.ipc.ac.cn; dyzhao@fudan.edu.cn
Abstract: Cyclometalated platinum(II) complex has been successfully incorporated into the (3-aminopropyl)
triethoxysilane-modified channels of ordered mesoporous silica SBA-15 that has large pore hexagonal
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channels. Studies on the O2 generation conclusively demonstrates that the olefins in the nano-channels
of SBA-15 can be enriched 8 times higher than those in the homogeneous solution as the diffusion quantum
yield of singlet oxygen (1O2) is assumed to be unit. The platinum(II) complex loaded in the channel of
SBA-15 is stable, and the photosensitized oxidation occurs efficiently. No obvious degradation and leaching
of photosensitizers is observed even after 10 runs. Only a simple filtration is needed for the recycled use
of the expensive noble metal catalysts. This versatile system is a good example of photochemical reactions
occurring in the mesoporous silica molecular sieve. SBA-15 not only provides a support for the
photosensitizer, but also acts as a nano-reactor to facilitate the photooxidation.
such as optical power limiting,3 electroluminescence,4 sensors,5,6
and multi-electron-transfer processes.7 In the context of the
Introduction
Square-planar platinum(II) polypyridyl complexes represent
an important class of compounds that possess a rich range of
spectroscopic and photophysical properties.1-10 Some of them
have demonstrated promising potentials in various applications,
photochemistry, this kind of complex has appeared at the
forefront due to its unique properties of open axial coordination
site and strong visible absorptions.1 Gray took the lead in
developing solar chemistry of metal complexes.8 Eisenberg and
our group have shown that the platinum(II) terpyridyl complexes
can be employed as photocatalysts to produce H2 from either
aqueous protons in the presence of a sacrificial electron donor
or Hantzsch dihydropyridine derivatives.9 More recently, we
have further employed platinum(II) polypyridyl complexes as
sensitizers for photooxidation using molecular oxygen,10 where
singlet oxygen (1O2) was generated upon irradiation of light in
visible region. However, these appealing features are out-
weighted by the relatively high costs and low stability in
solution, which make their synthetic application impractical.
Thus, seeking new photosensitizers or photosensitized systems
† Technical Institute of Physics and Chemistry, the Chinese Academy
of Sciences.
‡ Fudan University.
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10.1021/ja0648256 CCC: $33.50 © 2006 American Chemical Society
J. AM. CHEM. SOC. 2006, 128, 14685-14690
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