9051
The remarkably efficient exciton migration in DA - MOF is attributed to enhanced pi - conjugation through the addition of two acetylene moieties in the porphyrin molecule , which leads to greater Q - band absorption intensity and much faster exciton - hopping ( energy transfer between adjacent porphyrin struts ) .
 acetylene, porphyrin, porphyrin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 acetylene, porphyrin, porphyrin