Sterically hindered phthalocyanines: solid-phase interactions with carbon monoxide in matrix-entrapped thin functional films

摘要

A thin film comprising highly sterically hindered iron phthalocyanine derivatives incorporated into sol–gel networks shows effective sensitivity to carbon monoxide gas, when monitored by UV–visible absorption spectroscopy at 670 nm. The absorbance of a sol–gel thin film incorporating octaphenyl-di-tert-butylphthalocyanine iron(II) was particularly sensitive to carbon monoxide gas and showed a change in absorption after exposure to 1000 ppm CO gas for 1 min, while repetitive exposures produced only a limited loss of response. The optical response of the thin film gradually decreases with increasing temperature, and the binding energy for this sensing phenomenon was calculated to be 0.401 eV. The spectrum recovers at room temperature some 5 min after exposure to the gas.