Unusual picosecond 1(π, π*) deactivation of ruffled nonplanar porphyrins

Steve Gentemann, Craig J. Medforth, Tadashi Ema, Nora Y. Nelson, Kevin M. Smith, Jack Fajer, Dewey Holten

Research output: Contribution to journalArticlepeer-review

104 Citations (Scopus)


Time-resolved and steady-state optical data are presented for metal-free meso-tetraalkylporphyrins, H2T(alkyl)P. Introduction of bulky tertiary-butyl or adamantyl substituents at the meso positions induces large ruffling distortions of the macrocycle skeleton that give rise to highly novel photophysical properties of the porphyrins. These include ultrashort 1(π, π*) lifetimes of 10-50 ps at 296 K that, intriguingly, lenghten to 10-15 ns at 78 K, the typical timescale found at both temperatures for planar derivatives such as tetra(n-pentyl) and tetraphenyl porphyrins. The ability of the nonplanar ruffled porphyrins to undergo additional structural deformations in the excited singlet state likely underlies their dramatically enhanced rates of internal conversion.

Original languageEnglish
Pages (from-to)441-447
Number of pages7
JournalChemical Physics Letters
Issue number4-5
Publication statusPublished - Nov 3 1995

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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