Effect of metal ions on the absorption spectra and surface plasmon resonance of an azacrown indoaniline dye

The effects of the complexation of a metal ion with an azacrown indoaniline (ACIA) dye on absorption spectra were evaluated using the Pariser¯Parr¯Pople (PPP-MO) method. The ACIA dye carrying a monoazacrown moiety exhibited sensitivity to metal ion complexation using an optical sensor based on surface plasmon resonance (SPR). A multilayer sensing chip was prepared with the ACIA dye sensing layer coated on a gold layer. Using the ACIA dye as a metal ion sensing molecule, a highly selective response to Li+ was observed.