Synthesis and characterization of highly photoresponsive fullerenyl dyads with a close chromophore antenna-C60 contact and effective photodynamic potential

Long Y. Chiang, Prashant A. Padmawar, Joy E. Rogers-Haley, Grace So, Taizoon Canteenwala, Sammaiah Thota, Loon Seng Tan, Kenneth Pritzker, Ying Ying Huang, Sulbha K. Sharma, Divya Balachandran Kurup, Michael R. Hamblin, Brian Wilson, Augustine Urbas

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)

Abstract

We report the synthesis of a new class of photoresponsive C 60-DCE-diphenylaminofluorene nanostructures and their intramolecular photoinduced energy and electron transfer phenomena. Structural modification was made by chemical conversion of the keto group in C60(>DPAF-C n) to a stronger electron-withdrawing 1,1-dicyanoethylenyl (DCE) unit leading to C60(>CPAF-Cn) with an increased electronic polarization of the molecule. The modification also led to a large bathochromic shift of the major band in visible spectrum giving measureable absorption up to 600 nm and extended the photoresponsive capability of C60-DCE-DPAF nanostructures to longer red wavelengths than C60(>DPAF-C n). Accordingly, C60(>CPAF-Cn) may allow 2γ-PDT using a light wavelength of 1000-1200 nm for enhanced tissue penetration depth. Production efficiency of singlet oxygen by closely related C60(>DPAF-C2M) was found to be comparable with that of tetraphenylporphyrin photosensitizer. Remarkably, the 1O2 quantum yield of C60(>CPAF-C2M) was found to be nearly 6-fold higher than that of C60(>DPAF-C2M), demonstrating the large light-harvesting enhancement of the CPAF-C2M moiety and leading to more efficient triplet state generation of the C 60> cage moiety. This led to highly effective killing of HeLa cells by C60(>CPAF-C2M) via photodynamic therapy (200 J cm-2 white light). We interpret the phenomena in terms of the contributions by the extended π-conjugation and stronger electron-withdrawing capability associated with the 1,1-dicyanoethylenyl group compared to that of the keto group.

Original languageEnglish
Pages (from-to)5280-5293
Number of pages14
JournalJournal of Materials Chemistry
Volume20
Issue number25
DOIs
Publication statusPublished - 2010
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • Materials Chemistry

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