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Why are Solutions of C60-Piperazine Purple at pH 11?
Journal article   Peer reviewed

Why are Solutions of C60-Piperazine Purple at pH 11?

Hanying Xu, Jun Tian, Mikhail V. Korobov, Karl Sohlberg and Allan Smith
Fullerenes, nanotubes, and carbon nanostructures, v 15(4)
01 Jul 2007

Abstract

Jahn-Teller active vibrational mode piperazine mono adduct PM3, ZINDO(s) vibronic coupling
The C 60 -piperazine mono adduct was synthesized by the reaction of C 60 and piperazine. The saturated C 60 -piperazine aqueous solution was colorless when pH is 8 or below. A purple color was developed when pH is around 9 and the pink color is most intense at pH 11. The color of the C 60 -piperazine solution fades out when pH is approaching 12 from 11, and the solution remains colorless when pH is 13 or higher. The UV-Vis spectra of the C 60 -piperazine solution were recorded at pH 4, 11 and 14. The mono-protonated C 60 -piperazine was identified to be responsible for the purple color observed. The computational investigation of the un-protonated, mono-protonated and di-protonated C 60 -piperazine was conducted at the PM3 and ZINDO(s) levels of theory. Vibronic coupling of the Jahn-Teller active vibrational mode to the electronic transition was applied to re-generate the weak absorption between 550-600 nm in the UV-Vis spectrum of the mono-protonated C 60 -piperazine.

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Collaboration types
Domestic collaboration
International collaboration
Web of Science research areas
Chemistry, Physical
Materials Science, Multidisciplinary
Nanoscience & Nanotechnology
Physics, Atomic, Molecular & Chemical
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