Photophysical and photocatalytic behavior of nickel(II) 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin

Máté M. Major, O. Horváth, Melinda A. Fodor, L. Fodor, Zsolt Valicsek, Günter Grampp, Alexander Wankmüller

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7 Citations (Scopus)

Abstract

Kinetically inert cationic Ni(II)TMPyP4 + (H2TMPyP4 + = 5,10,15,20-tetrakis(methylpyridinium-4-yl)porphyrin) displayed a characteristic fluorescence (τ = 1.2–1.4 ns, Φ = 2.0 × 10− 3), which was quenched with triethanolamine (TEOA) in a static way. This complex proved to be an efficient photocatalyst in the system containing TEOA and methylviologen (MV2 +) as electron donor and acceptor, respectively. Interestingly, however, deviating from the behavior of the analogous Co(III) and Mn(III) complexes in such a system, TEOA did not dynamically quench the triplet excited state of Ni(II)TMPyP4 + (τ = 6.31 μs), hence no reduction of the metal center occured upon irradiation. Instead, in the presence of this electron donor (at 1 × 10− 3 M) the excited-state lifetime dramatically increased (to τ = 36.6 μs), indicating the formation of a Ni(II)TMPyP4 +-TEOA associate. This longer-lived triplet was efficiently quenched by MV2 + (kq = 9.9 × 106 M− 1 s− 1), leading to the formation of MV•+. The overall quantum yield of this one-step photoassisted electron transfer is considerably high (Φ = 0.011–0.013 at Soret-band irradiation). Hence, this system, combined with a suitable co-catalyst, may be applicable for visible light-driven hydrogen generation from water.

Original languageEnglish
Pages (from-to)1-3
Number of pages3
JournalInorganic Chemistry Communications
Volume73
DOIs
Publication statusPublished - Nov 1 2016

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Keywords

  • Fluorescence
  • Nickel(II) porphyrin
  • Photocatalysis
  • Static and dynamic quenching
  • Triplet state
  • Water-soluble

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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