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. Zirconium-phenolate open frameworks based on metalloporphyrin, which are fairly robust in the alkaline conditions, exhibit enhanced third-order optical nonlinearity in comparison with the metal-free counterpart in the porphyrin core. Image 1 • Zr-phenolate open structures remain intact in some common solvents. • Zr-pyrogallol porphyrinic nets exhibit nonlinear optical limiting effect. • Optical limiting performance could be greatly improved by the metal chelation. [ABSTRACT FROM AUTHOR]