Second Generation Nanostructured Metal Oxide Matrices to Increase the Thermal Stability of CO and NO₂ Sensing Layers Based on Iron(II) Phthalocyanine

Abstract

An iron(II) phthalocyanine (FePc) complex solubilized by decylamine (DA) and benzylamine (BA) is incorporated into a nanoparticulate metal oxide matrix to develop optical sensor films sensitive to NO2 and CO. Eleven amine solvents have been tested as N‐donor ligands that permit ligand exchange with the gas molecules. We have systematically investigated the suitability of different N‐donor ligands, studied the thermal stability of the NO2‐ and CO‐sensing films at 4, 25, 60, and 80 °C by photometry, and corroborated our findings by using NMR experiments. A satisfactory thermal stability of the films has not been obtained for chemically unmodified nanoparticulate metal oxide matrices. We have therefore developed a second generation of nanostructured metal oxide supports that show increased thermal stability and adequate sensitivity to NO2 and CO. These novel nanostructured matrices have been chemically modified using amines, alumina oligomers, and/or anti‐gas‐fading agents. These components have been integrated into the metal oxide matrices to avoid degradation of the optical films and to preserve their sensitivity.

Copper(i) complexes as alternatives to iridium(iii) complexes for highly efficient oxygen sensing

“…It is due to the high hydrophilicity of this matrix, which had been previously pointed out. 7,20 Thus, 1-AP200/19 is more useful for gaseous analysis and the relative humidity of the environment has to be taken into account during the calibration of the sensing film.…”

Iron-phthalocyanine complexes immobilized in nanostructured metal oxide as optical sensors of NOx and CO: NMR and photophysical studies

“…To evaluate the N-donor ligand effect the fi lms prepared were characterized by measuring the relative change in absorbance at λ max (see Table 1) and by NMR measurements at room temperature [14]. The experimental results show that DBA, BEHA, PRL and IND coordinate badly to FePc, probably due to sterical hindrance; the secondary amines DOA, PRLD and PRLN provide fi lms which do not respond at all to NO 2 or CO, or with very low sensitivity (low A 0 and ∆A/A 0 < 1%); the aromatic amines pDA and IMD were able to dissolve the metal complex and seem to be coordinated to the metal center in a stable molar ratio (λ max = 662-664 nm) but provide sensing fi lms which do not respond reversibly to NO 2 ; and, only the primary amines DA and BA provide reversible and sensitive sensing fi lms for both NO 2 and CO gas.…”

Effect of pyridine on zinc phthalocyanine studied by density functional theory calculations and infrared absorption spectroscopy

“…Phthalocyanine (Pc) and its metal analogous (MPc) possess interesting physico-chemical properties, which have the potential for applications in the area of non-linear optic, acoustics, gas sensing, magnetic materials, photoconducting agents, photovoltaic cell elements, electrocatalysis, colorants in chemical industry, optical data storage, photosensitizers, light emitting diodes and dyes [1][2][3][4][5][6][7]. In these materials, excellent chemical tunability of properties can be achieved by replacing metal ions at the center of the phthalocyanine (Pc) ring and functionalizing their side groups/axial positions.…”