Some Hybrid Systems of Chiral Schiff Base Zn(II) Complexes and Photochromic Spiropyrans for Environmental Ion Sensing

Abstract

This is a review article including our recent results and some previous photo functional hybrid system having potential applications for environmental ion sensing. We have prepared several new and known chiral Schiff base Zn(II) complexes and measured (and also calculated) absorption and fluorescence spectra for sole complexes. After assembling hybrid systems with 1,3,3-trimethylindolino-6'-nitrobenzopyrylospiran (SP) in methanol solutions, we measured spectral changes before and after alternate irradiation of UV and visible light. Intensity of fluorescence spectra for pale yellow Zn(II) complexes (λem = 450 nm, λex = 270 and 360 nm) was quenched by colorless SP (λem = 533 nm, λex = 612 nm). After UV light irradiation to form purple merocyanine (MC), photoisomerization resulted in changes of the intensity of absorption spectra as well as fluorescence spectra. Thus the hybrid systems could successfully act as molecular logic circuit by input (excitation by light) and output (intensity of fluorescence peaks). Moreover, we investigated concentration dependence of doped Zn(II) and Cu(II) ions to confirm quenching of intensity of fluorescence peaks by Zn(II) and Cu(II) MC complexes for metal ion sensing in solutions.

Computational Treatments of Hybrid Dye Materials of Azobenzene and Chiral Schiff Base Metal Complexes

“…For about a decade, we have systematically investigated photofunctional organic/inorganic hybrid materials containing photochromic organic dyes, such as azobenzene (AZ) [7][8][9][10][11], disperse red 1 [11], spiropyran [12,13], and inorganic metal complexes, such as (chiral) Schiff base [14][15][16][17][18] (especially related to salen-type [19][20][21][22]) or other magnetic complexes [23][24][25][26][27]. To form hybrid systems in the solid state, in addition, polymer matrix, e.g., polymethyl methacrylate (PMMA) or polyvinyl alcohol (PVA) [23,28], were also employed.…”