Optical limiting properties of metalloporphyrin-based zirconium-polyphenolate frameworks

As lasers are used more extensively, protection from lasers is becoming increasingly important. Human eyes and many optical sensors are so sensitive to 532 nm wavelength lasers that laser protection at this wavelength is extremely critical. We demonstrate here that a series of exceptionally stable and isoreticular zirconium-polyphenolate-porphyrin frameworks, ZrPP-n-H-2 (n = 1, 2) and ZrPP-1-M (M = Fe, Ni, Cu, Zn, Mn and Co) exhibit nonlinear optical (NLO) limiting properties. Compared with ZrPP-1-H-2 at the same transmittance, there was no obvious improvement of NLO limiting performance for the extended version of ZrPP-2-H-2. However, the NLO limiting behaviors were greatly improved when ZrPP-1-H-2 involved chelated metal ions, especially Mn or Co ions in a porphyrin ring. Our results indicate that while the NLO limiting effects may not be improved by extending the ligand for metalloporphyrin-based networks, but they can be greatly improved by the introduction of the appropriate metal ions into a porphyrin core. This work may provide a new insight into laser protection by microporous coordination materials.