Upon addition of CN− increasing from
0 to 100 equiv., a new obvious emission peak centered at 504 nm
was observed and obviously enhanced with the increase of CN−. By
fluorescence titration, the binding constant between HNA and CN−
was determined to be about (4.571
±
0.1)
×
103M−1 and the detection
limit of HNA toward CN− was obtained as 4.4
×
10−6 mol L−1
(Supplementary data, Fig. S6), which is sufficiently low for the
detection of the CN− found in many chemical systems. And from
the mass data for HNA–CN− conjugate, the 1:1 stoichiometry ratio
between HNA and CN− was proposed