3568
Factors in polypyridyl ligands that control their thermodynamic metal ion selectivity in aqueous solution , and their use in selective fluorescent sensing , are examined .
 Chemical: polypyridyl
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: polypyridyl