Fluoro-Substituted Metal Phthalocyanines for Active Layers of Chemical Sensors

Metal phthalocyanines bearing electron-withdrawing fluorine substituents were synthesized a long time ago, but interest in the study of their films has emerged in recent decades. This is due to the fact that, unlike unsubstituted phthalocyanines, films of some fluorinated phthalocyanines exhibit the properties of n-type semiconductors, which makes them promising candidates for application in ambipolar transistors. Apart from this, it was shown that the introduction of fluorine substituents led to an increase in the sensitivity of phthalocyanine films to reducing gases. This review analyzes the state of research over the last fifteen years in the field of applications of fluoro-substituted metal phthalocyanines as active layers of gas sensors, with a primary focus on chemiresistive ones. The active layers on the basis of phthalocyanines with fluorine and fluorine-containing substituents of optical and quartz crystal microbalance sensors are also considered. Attention is paid to the analysis of the effect of molecular structure (central metal, number and type of fluorine substituent etc.) on sensor properties of fluorinated phthalocyanine films.

Preparation and electrochemical properties of cobalt-phthalocyanine-decorated Fe3O4 nanoparticles

Phthalocyanines (Pcs) have been known for excellent electron transfer properties owing to their extended [Formula: see text]-conjugated structures. In addition, functionalized iron oxide nanoparticles (Fe[Formula: see text]O[Formula: see text] NPs) have attracted considerable interest owing to their unique spectral and electronic properties. Hence, it can be reasonably expected that Fe[Formula: see text]O[Formula: see text] NPs decorated with Pc molecules could provide a useful electrocatalytic system. Herein, we present the preparation and electrochemical properties of cobalt-phthalocyanine (CoPc)-decorated Fe[Formula: see text]O[Formula: see text] NPs (CoPc@Fe[Formula: see text]O[Formula: see text]. The Fe[Formula: see text]O[Formula: see text] NPs were first coated with a silica layer to produce SiO[Formula: see text]@Fe[Formula: see text]O[Formula: see text]. Subsequently, CoPc with a siloxane end group (CoPc-TEOS) was anchored to the outer surface of the SiO[Formula: see text]@Fe[Formula: see text]O[Formula: see text]. The CoPc@Fe[Formula: see text]O[Formula: see text] thus prepared was fully analyzed using various characterization methods. Distinctive electrochemical responses of CoPc and CoPc@Fe[Formula: see text]O[Formula: see text] in the presence of picric acid were observed, demonstrating the potential application of the current approach to electrochemical catalysis.