A condensation to quinoid systems occurs . 发生了醌型体系的缩合反应。
2.
When the ph of the solution was lower than 4 , the structure of dab changes from an azo type to a quinoid type . this change was studied by sers and the reversibility of transformation was found 当溶液ph值小于4时，由于质子化， dab分子将从偶氮型结构转变为醌型结构，本章利用sers技术，研究了其结构的这种变化，并且发现这种结构的变化是可以逆转的。
