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

摘要

The metal(Ⅱ) coordinating anion 2-(5-amino-3,4-dicyano-2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide (C_(11)N_7H_2~-, L′, λ_(max) = 549 nm, ε_(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 monoch-elated 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 CN~- in 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.