[Study on influence of pH on interaction of cucurbit[n=7,8] uril with two naphthylamine isomers].
The interaction of cucurbit[n=7,8]urils (Q[7], Q[8]) with two naphthylamine isomers and the influence of pH on the interaction were studied by using UV-Vis spectroscopy and 1H NMR technique. The experimental results revealed that Q[7] always forms a 1:1 complex with the naphthylamine isomers respectively in the pH range (-0.3<pH<8) and the interaction of Q[7] with the title guests was not observed in the 8<pH<14 range. However, there are five interaction stages for Q[8]-naphthylamine isomer systems, no obvious interaction between the host Q[8] and the title naphthylamine guest(s) at the "highest" and the "lowest" pH (pH>14 and pH<-0.3 respectively); the Q[8] could include the guest with a 1:1 ratio between the "highest" and a "higher" pH or the "lowest" and a "lower" pH (-0.3<pH<4 and 9.5<pH<14); between the higher and the lower pH (4<pH<9.5), the Q[8] includes the guest and forms a inclusion complex with 1:2 ratio of host to guest.
Institute of Applied Chemistry, Guizhou University, Guiyang 550025, China.
Qi-Hua
QH
Zeng
Zhu
Z
Tao
Sai-Feng
SF
Xue
Qian-Jiang
QJ
Zhu
Lan
L
Mu