Fluorescence Sensing of Anions by Silanediols Bearing Substituted Naphthyl Groups

Silanediols bearing naphthyl moieties substituted at 5‐position with an electron‐withdrawing cyano group and an electron‐donating N,N‐dimethylamino group, respectively, have been prepared and characterized. The substituents on the naphthyl moieties strongly influence the reactivity, photophysical properties, and sensing abilities for anions. The silanediol bearing 1‐(5‐N,N‐dimethylaminonaphthyl) groups exhibited large Stokes shifts based on intramolecular charge transfer and large quantum yields in organic solvents. The silanediol showed favorable ratiometric fluorescence responses of upon the addition of biologically important anions, AcO− and H2PO4− with the association constants of 4.08×104 and 8.76×103 mol−1 dm3, respectively. Silanediols bearing substituted naphthyl moieties were synthesized. Photophysical and anion binding properties of the silanediols were evaluated. The silanediol bearing N,N‐dimethylaminonaphthyl groups showed ratiometric fluorescence response to basic oxoanions.