Nonlinear absorption properties of 5,10-A2B2porphyrins—correlation of molecular structure with the nonlinear responses

Abstract

The nonlinear absorption properties of two series of novel free base and metalated meso 5,10-A 2 B 2 substituted porphyrins, both bearing p-tolyl as an A substituent and TMS-ethynyl or bromine as a B substituent, were investigated with the open Z-scan technique at 532 nm in the ns time regime. Most of the compounds exhibited a transmission drop with increasing input fluence. This behavior is desirable for their applications in optical limiting. More complex responses: a drop in transmission followed by an increase in transmission or an increase in transmission followed by a transmission drop, with increasing input fluence, were detected for certain compounds. All of the recorded responses were successfully fitted with a four-level model with simultaneous two-photon absorption arising from the higher excited states (consecutive one-+ one-+ two-photon absorption). The TMS-ethynyl group was found to be a more efficient meso substituent in optical limiting than the bromine atom. Indium, lead and zinc complexes with TMS-ethynyl substituents were the strongest positive nonlinear absorbers amongst compounds studied which makes them the most interesting candidates for optical limiting application.

Chirogenesis in Zinc Porphyrins: Theoretical Evaluation of Electronic Transitions, Controlling Structural Factors and Axial Ligation

“…based on the absorption spectra reported that the energies of the B‐bands of [5,15‐bis[(aryl)ethynyl]‐10,20‐diphenyl‐porphinato]zinc(II) complexes are up to 20 nm shifted to the lower energy region as compared to the complex with phenyl substituents. In different zinc porphyrins with various meso ‐substituents experimentally studied by Zawadzka et al [35,127] . the B‐bands were shifted by 12–17 nm.…”

Structural investigation of 5,10-A2B2-type porphyrins: palladium(II) and zinc(II) complexes of 5,10-dibromo-15,20-bis(4-methylphenyl)porphyrin

“…This has now become possible with the advent of general syntheses for 5,10-disubstituted porphyrins (Ryppa et al, 2005). These have been used to develop 5,10-A 2 -15,20-B 2 -type porphyrins, (II) (see Scheme), for optical applications due to the altered orientation of the intramolecular dipole moment compared to the well-known 5,15-A 2 -10,20-B 2 systems, (III) (Senge et al, 2011;Zawadzka et al, 2013a). Here, we use 5,10-dibromo-15,20-bis(4-methylphenyl)porphyrin, (IV), and its palladium(II), (V), and zinc(II), (VI), complexes for a comparative analysis of their structural properties.…”

Studying the intersystem crossing rate and triplet quantum yield of meso-substituted porphyrins by means of pulse train fluorescence technique

“…Very fast excited state absorption and high singlet to triplet conversion rates [10][11][12] make porphyrins a unique class of compounds for this application [13][14][15]. Besides OPL, the ISC features of porphyrins are also important for other applications such as photodynamic therapy (PDT) [1,16], dye sensitized solar cells [17] and photon up-conversion devices [18].…”