Single-wall carbon nanotubes bearing covalently linked phthalocyanines - Photoinduced electron transfer

Abstract

HiPco single-walled carbon nanotubes (SWNTs) have been sidewall-functionalized with phthalocyanine addends following two different approaches:  a straightforward Prato reaction with $N$-octylglycine and a formyl-containing phthalocyanine, and a stepwise approach that involves a former Prato cycloaddition to the double bonds of SWNTs using $p$-formyl benzoic acid followed by esterification of the derivatized nanotubes with an appropriate phthalocyanine molecule. The two materials obtained by these routes comprise different carbon/Pc-addenda ratios, as evidenced by Raman, TGA, and photophysical studies. The occurrence of electron transfer from photoexcited phthalocyanines to the nanotube framework in these ZnPc-SWNT ensembles is observed in transient absorption experiments, which confirm the absorption of the one-electron oxidized ZnPc cation and the concomitant bleaching of the van Hove singularities typical from SWNTs. Charge-separation (i.e., $2.0 \times 10^{10}$ s$^{-1}$) and charge-recombination (i.e., $1.5 \times 10^6$ s$^{-1}$) dynamics reveal a notable stabilization of the radical ion pair product in dimethylformamide.

Publication
J. Am. Chem. Soc. 129, 5061–5068 (2007)

Full citation
B. Ballesteros, G. de la Torre, C. Ehli, G. M. A. Rahman, F. Agulló-Rueda, D. M. Guldi, and T. Torres, “Single-wall carbon nanotubes bearing covalently linked phthalocyanines - Photoinduced electron transfer,” J. Am. Chem. Soc. 129, 5061–5068 (2007). DOI: 10.1021/ja068240n

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