In the case of chemiluminescence of coelenterazine, effects of conformation rigidity of and hydrogen bonding with the emitter, coelenteramide, on the chemiluminescence efficiency have been examined with several coelenterazine analogues synthesized. Conformational rigidity has a light enhancing effect, whereas decreasing light yield was observed by hydrogen-bond formation with the emitter.
![[4-(2,3-dioxopropyl)phenyl] acetate Structure](https://image.chemsrc.com/caspic/418/56071-70-6.png)
![2-benzyl-8-(benzyloxy)-5,6-dihydrobenzo[f]quinoxalin-3-amine Structure](https://image.chemsrc.com/caspic/350/132063-72-0.png)