13462
The receptor dissolved in water with neutral pH shows almost no fluorescence due to the photoinduced electron transfer ( PET ) from the amide and amine nitrogens to the excited state coumarin moiety .
 amide and amine nitrogens, coumarin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 amide and amine nitrogens, coumarin