Nonlinear absorption dynamics in tetrapyridyl metalloporphyrins

J Phys Chem B. 2005 Sep 15;109(36):17340-5. doi: 10.1021/jp052168i.

Abstract

Nonlinear absorption dynamics of Zn(2+), Cu(2+), and Ni(2+) tetrapyridyl porphyrins in chloroform/methanol solutions were investigated at 532 nm with the Z-scan technique. Additional techniques such as UV-vis absorption spectroscopy and time-resolved fluorescence were used to obtain parameters that are important for the analysis of the population dynamics. A marked difference was observed in the nonlinear absorption and excited-state dynamics of closed (ZnTPyP)- and open-shell metalloporphyrins (CuTPyP and NiTPyP). ZnTPyP presents a reverse saturable absorption whose dynamics can be completely described by means of a simple five-energy-level diagram. On the other hand, CuTPyP and NiTPyP have a different excited-state dynamics, presenting a saturable absorption behavior and faster relaxation rates that were attributed to the presence of unfilled d shells of the central ion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Metalloporphyrins / chemistry*
  • Pyridines / chemistry*
  • Spectrum Analysis / methods

Substances

  • Metalloporphyrins
  • Pyridines
  • pyridine