Self-assembly and nonlinear optical properties of (μ-oxo)bis[meso-tetrakis(p-bromophenyl-porphyrinato)iron(iii)]

Abstract

A sandwich-type dimer, namely (μ-oxo)bis[tetrakis(p-bromophenyl-porphyrinato)iron(III)], [(TBPP)Fe]₂O, was prepared under solvothermal conditions and structurally characterized for the first time. Its self-assembly behavior has been comparatively investigated with the monomer [(TBPP)Fe]Cl by electronic absorption spectroscopy, scanning electron microscopy (SEM), and powder X-ray diffraction (PXRD) with the help of single crystal analysis. The optical properties of both compounds were studied by an open aperture Z-scan technique, revealing their good third-order nonlinear optical (NLO) properties. In particular, the μ-oxo dimer shows an about one order of magnitude larger two-photon absorption (TPA) cross-section (σ) value than the monomer due to its more extended conjugated electronic structure.