Substituent Effect on Porphyrin Film-Gas Interaction by Optical Waveguide: Spectrum Analysis and Molecular Dynamic Simulation

Abstract

Substituent effect on optical gas sensing performance in porphyrin-based optical waveguide detection system was studied by molecular dynamics simulation (MDS), absorption/emission spectrum analysis, and optical waveguide (OWG) detection. The affinities of porphyrin with seven types of substituents (–H, –OH, –tBu, –COOH, –NH2, –OCH3, –SO3−) on para position of meso-phenyl porphyrin toward gas molecules in adsorption process were studied in different size of boxes with the same pressure and concentration. Analyte gases (CO2, H2S, HCl, NO2) were exposed to porphyrin film in absorption spectrophotometer, and in OWG with evanescent field excited by a guiding laser light with 670 nm wavelength. The extent of interaction between host molecule and the guest analytes was analyzed by the number of gas molecules in vicinity of 0.3 nm around substituents of porphyrin molecules. Optical waveguide results reveal that sulfonate porphyrin is mostly responsive to hydrochloride, hydrosulfide gas and nitrogen dioxide gases with strong response intensity. Molecular dynamics and spectral analysis provide objective information about the molecular state and sensing properties. Molecular rearrangements induced by gas exposure was studied by spectral analysis and surface morphology before and after gas exposure taking hydrosulfide gas as an example. Film-gas interaction mechanism was discussed in terms of each gas and substituent group characters.

Supercapacitance in graphene oxide materials modified with tetrapyrrole dyes: a mechanistic study

“…On the basis of the absorption spectra of the composites (Fig. 4a), reported molar absorption coefficients and well defined absorption peaks (Soret bands: 616 000 M −1 cm −1 for THPP, 632 000 M −1 cm −1 for TCPP and Q bands: 150 000 M −1 cm −1 for CuPC and assumed also for CuTAPC on the basis of molecular similarity) 43,61,62 the modifier: GO ratios have been determined. Supramolecular composites contain 0.94, 048, 0.89, and 1.26% v/v (which corresponds to loadings of 13.8, 6.04, 15.18 and 21.74 μmol g −1 of GO) of tetrapyrrolic modifiers for THPP, TCPP, CuPC and CuTAPC, respectively.…”

Metallic Effects on p-Hydroxyphenyl Porphyrin Thin-Film-Based Planar Optical Waveguide Gas Sensor: Experimental and Computational Studies

“…The film–analyte interaction mechanism and output light intensity has been restricted to the macroscopic view. Recently, our studies have focused on the effect of substituents from a microscopic view using molecular simulation [ 20 ]. In this work, the effect of metal centers in p-hydroxyphenyl substituted porphyrin thin film, with various transition metals, in optical waveguide towards NO 2 gas, was studied with instrumental ways, molecular dynamics simulation, and quantum mechanical calculation.…”