Thiophene and furan appended pyrazoline based fluorescent chemosensors for detection of Al3+ ion

摘要

Thiophene and furan appended pyrazoline receptors R1 and R2 were designed and synthesized for selective detection of Al3+ ion. Their photophysical properties were studied by UV-visible and fluorescence spectra. Surprisingly, both receptors R1 and R2 were displayed an excellent selective and sensitive response to Al3+ ion alone over other tested metal ions. Both the receptor R1 and R2 displays 1:1 stoichiometry for [R1-Al3+] and [R2-Al3+] complex and formed with an association constant of 1.84 x 10(4) M-1 and 1.92 x 10(4) M-1 respectively. The limit of detection were calculated for R1 and R2 since 8.92 x 10(-8) M and 1.04 x 10(-7) M by the fluorescence titration method. The thiophene based receptor R1 exhibited superior chemosensor characteristics such as high intensity absorption and emission at longer wavelength as compered that of furan based receptor R2.