Investigation on the UV spectra of the supermolecular system involving silver nanoparticles–substituted N‐(phenyl‐ethylene)‐anilines

Abstract

The ultraviolet (UV) absorption spectra of the supermolecular system involving silver nanoparticles–substituted N‐(phenyl‐ethylene)‐anilines were investigated. Silver nanoparticles (AgNPs) and 77 kinds of substituted N‐(phenyl‐ethylene)‐anilines ZArC (Me)═NArY (ZPEAY, including 40 compounds 2‐H‐XPEAY without ortho‐hydroxyl and 37 compounds 2‐OH‐XPEAY with ortho‐hydroxyl) were prepared. The size of AgNPs was measured with transmission electron microscopy. To study the effect of substituents X and Y on the UV spectra of the supermolecular system of AgNPs‐ZPEAY, the authors measured the UV absorption spectra of AgNPs, ZPEAY, and AgNPs‐ZPEAY solutions. The experimental results show that (a) the size of AgNPs increases in AgNPs‐ZPEAY solution compared with that in AgNPs solution, due to the absorption of ZPEAY molecules on the surface of AgNPs; (b) the UV absorption wavelength of ZPEAY changes in AgNPs‐ZPEAY solution and there is a limitation for the wavelength shift (λWSL) between ZPEAY and AgNPs‐ZPEAY system; (c) there is a quantitative correlation between the wavenumber ΔνWSL of λWSL and the substituent constants (Hammett constant σ and excited‐state substituent constant σCCex) of substituents X and Y; (d) the intramolecular hydrogen bonding in 2‐OH‐XPEAY makes the ΔνWSL a red shift in AgNPs‐ZPEAY system.