25904
DNA - binding , photocleavage , cytotoxicity in vitro , apoptosis and cell cycle arrest studies of symmetric ruthenium ( II ) complexes .
 Chemical: ruthenium ( II )
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ruthenium ( II )