Web Release Date: February 21,
Solvent-Controlled Photoinduced Electron Transfer between Porphyrin and Carbon Nanotubes
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. China
Received November 6, 2007
Abstract:
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-Cyclodextrin (-CD)-modified multiwalled carbon nanotubes (MWCNTs) were successfully prepared
by reaction of surface-bound carboxylic chloride groups of MWCNTs with aminoethyleneamino-deoxy--CD (ENCD) and comprehensively characterized by FTIR, Raman, and X-ray photoelectron spectroscopy
and thermogravimetric and differential thermal analysis. The -CD-modified MWCNTs (ENCD-MWCNTs) are highly water-soluble, with a solubility of ca. 9.0 mg·mL-1. Furthermore, the photoinduced
electron transfer (PET) process between tetrakis(4-carboxyphenyl)porphyrin (TCPP) and ENCD-MWCNTs
was investigated by means of fluorescence, fluorescence decay, transient absorption spectroscopy, and
cyclic voltammetry. Obvious quenching processes were observed upon addition of both MWCNT-COOH
and ENCD-MWCNTs to the aqueous solutions of TCPP, indicating that the PET process between TCPP
and carbon nanotubes takes place upon irradiation. When 1-adamantane acetic acid was added to the
aqueous solutions of TCPP/MWCNT-COOH and TCPP/ENCD-MWCNTs, respectively, the former
fluorescence remains, while the latter fluorescence recovers. On the contrary, the fluorescence intensity
of TCPP in the DMF solution was hardly decreased upon addition of ENCD-MWCNTs, whereas its
fluorescence was quenched in the presence of MWCNT-COOH. The observations indicate that the CD
cavities play a vital role on the control of the PET process.
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