Cucurbit[8]uril-stabilized charge transfer complexes with diquat driven by pH: a SERS study

摘要

In this work, we have studied the pH-dependence of the formation of DQCB[8] complexes by surface-enhanced Raman scattering (SERS) spectroscopy. The SERS spectra suggest that at acidic pH CB[8] can form a binary complex with the dication DQ~(+2) while at higher pH ternary complexes with the radical cation dimer (DQ~(+·))2 and the radical cation-dication dimer (DQ~ (+·)DQ ~(+2)) are formed. The pH-enhanced diquat (DQ) dimerization inside the cucurbit[8]uril cavity has not been reported until now. In addition, this study provides very valuable information regarding the use of CB[8] functionalized silver nanoparticles as SERS substrate for sensing applications.