Sol−Gel Hybrid Silica Thin Films Doped with 2-(5-Amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide as Optical Chemical Sensors

Abstract

The metal(II) coordinating anion 2-(5-amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide (C 11 N 7 H 2 -, L′, λ max ) 549 nm, max ) 35 000 M -1 cm -1 ) has been incorporated as dispersed monomer at a fairly high concentration (c ≈ 0.06 M) in a thin film (thickness < 1 µm) of a two-component (poly(methyl methacrylate)/SiO 2 ) glass. L′ in the film reacts specifically with Hg 2+ , as mercury(II) acetate, in water, forming the corresponding monochelated pyrrolizinato complex, >HgL (λ max ) 670 nm). A color change from violet to blue occurs along with this transformation. The >HgL-doped film releases L′ in the matrix after interaction with small molecules, such as CNin water or NH 3 in the gas phase, generating the associated reversal color change to violet. These systems have been investigated for future adaptation as optical chemical sensors.

Chemical Sensors Based on Molecularly Imprinted Sol-Gel Materials

“…Thin silane films have found numerous applications for optical sensing of several ionic species such as different metal ions [ 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. Sol-gel materials help us detect metal ions in two ways: firstly, the silane groups offer sufficient sensing sites to metal ions as they possess a large surface area, and secondly, due to the presence of entrapped recognition molecules.…”

Preparation and Dielectric Property Investigation of Ferrocene/Poly(vinyl pyrrolidone) Composite Membranes

“…industrial applications. 6 7 That is because of their utility and potential as catalysts, 8 sensors, 9 optical and electronic applications, 10 gas selective membranes, 11 etc. In general, composite materials are formed when at least two different types of materials (organic, inorganic, or metallic) are mixed.…”

Fluorescence and physical characterization of sol–gel-derived nanocomposite films suitable for the entrapment of biomolecules

“…18 Third, high levels of alcohol are often required as a viscosity modifier to allow proper formation of a dip-cast thin film, 28 leading to denaturation of the encapsulated biomolecules. 21 Finally, thin films undergo substantial changes in structure and solvent content on a short timescale during the aging and drying process, 28 potentially leading to extensive cracking 29,30 and dehydration of encapsulated biologicals. 5,31,32 The primary objective of this work is to prepare and characterize sol-gel-derived thin films formed via the dip casting method that cover the range of undoped, Class I, Class II, and Class I/II organic-inorganic nanocomposites.…”