Single molecule spectroscopic investigation on conformational heterogeneity of directly linked zinc(II) porphyrin arrays

Mira Park, Sung Cho, Zin Seok Yoon, Naoki Aratani, Atsuhiro Osuka, Dongho Kim

Research output: Contribution to journalArticle

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Abstract

We have comparatively investigated the photophysical properties of a series of meso-meso directly linked orthogonal porphyrin arrays (Zn, n = 1, 2, 3, 4, 6, 8, 9, 12, 16, 32, 48, 64, and 96) by ensemble average and single molecule fluorescence spectroscopy. In single molecule fluorescence study, we have recorded the fluorescence intensity trajectories of Zn arrays as the number of porphyrin molecules in the array increases. Up to Z8 in porphyrin arrays, each single array exhibits multiple stepwise photobleaching behaviors in fluorescence intensity trajectories, indicating that each porphyrin unit in the array acts as an individual fluorescent unit due to a maintenance of linear rigid structure of the array. On the other hand, porphyrin arrays longer than Z8 such as Z16, Z32, Z48, and Z64 show complicated photobleaching behaviors in fluorescence intensity trajectories. The origin of complex photobleaching behaviors is believed to be increasing nonradiative decay channels contributed by the enhanced structural nonlinearity in longer arrays. The fluorescence measurements of Zn arrays on single molecule level show a mismatch in the maximum fluorescence intensity level as compared to the solution measurements, which is attributable to the difference in local environment surrounding the porphyrin array. In this work, we have demonstrated the presence of conformational heterogeneity in longer porphyrin arrays by analyzing average survival times and fluorescence spectra of single arrays as the number of porphyrin molecules in the array increases. We believe that the fluorescence properties of porphyrin arrays on single molecule level will provide a platform for further applications as molecular photonic wires.

Original languageEnglish
Pages (from-to)15201-15206
Number of pages6
JournalJournal of the American Chemical Society
Volume127
Issue number43
DOIs
Publication statusPublished - 2005 Nov 2

Fingerprint

Porphyrins
Zinc
Fluorescence
Molecules
Photobleaching
Trajectories
Optics and Photonics
Rigid structures
zinc hematoporphyrin
Fluorescence Spectrometry
Fluorescence spectroscopy
Photonics
Maintenance
Wire

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Park, Mira ; Cho, Sung ; Yoon, Zin Seok ; Aratani, Naoki ; Osuka, Atsuhiro ; Kim, Dongho. / Single molecule spectroscopic investigation on conformational heterogeneity of directly linked zinc(II) porphyrin arrays. In: Journal of the American Chemical Society. 2005 ; Vol. 127, No. 43. pp. 15201-15206.
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Single molecule spectroscopic investigation on conformational heterogeneity of directly linked zinc(II) porphyrin arrays. / Park, Mira; Cho, Sung; Yoon, Zin Seok; Aratani, Naoki; Osuka, Atsuhiro; Kim, Dongho.

In: Journal of the American Chemical Society, Vol. 127, No. 43, 02.11.2005, p. 15201-15206.

Research output: Contribution to journalArticle

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AU - Cho, Sung

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AU - Osuka, Atsuhiro

AU - Kim, Dongho

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