Cubic nonlinear optical properties of new zinc tetraphenyl porphyrins peripherally functionalized with electron-rich Ru(II) alkynyl substituents

We report the synthesis and characterization of new organometallic assemblies consisting of a central Zn(II) tetraphenylporphyrin (ZnTPP) core surrounded by four Ru(II) alkynyl complexes (trans-Ru(dppe)2R) appended at the para phenyl positions and acting as peripheral donor groups. The synthesis of the tetra-chlorido derivative 2 (R=Cl) is reported first, followed by that of three extended homologues (3–X) obtained from this building block by substitution of the chlorido ligands by functionalized arylacetylenes (R=Ctriple bond; length of mdashC(4-C6H4X); X=NO2, H, OMe). Measurement of the nonlinear absorption properties of the pentametallic derivatives 3–X reveals that these extended π-networks incorporating polarizable organometallic units behave as good two-photon absorbers in the visible and near-IR range.