Organic/polyoxometalate hybridization dyes: Crystal structure and enhanced two-photon absorption

The structures of four novel organic–inorganic hybrid dyes, namely trans-4-(4′-(N,N-Dialkylaminostyryl))-N-Methyl-pyridinium[Mo6O192−] [alkyl = Et(POM1), Pr(POM2), n-Bu(POM3) and Me, hydroxyethyl(POM4)], were characterized by single crystal X-ray diffraction analysis. Hybridization of the organic chromophores with polyoxometalate enhanced their two-photon absorption cross sections and thermal stability. The linear optical properties of the hybrid dyes were investigated using absorption and fluorescence spectra in both the solution and solid states. The two-photon absorption cross section δ and coefficient β were obtained using the Z-scan technique. Correlations between dye structure and optical property were investigated.