6234
We describe complexes of ruthenium and europium with rigid , 5 ' - 6 - locked 1 , 10 - phenanthroline - containing nucleosides .
 ruthenium, europium, 1 , 10 - phenanthroline, nucleosides
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 ruthenium, europium, 1 , 10 - phenanthroline, nucleosides