17976
In contrast to pristine zinc phthalocyanine ( 1 ) , zinc phthalocyanine based oPPV - oligomers ( 2 - 4 ) of different chain lengths interact tightly and reversibly with graphite , affording stable and finely dispersed suspensions of mono - to few - layer graphene - nanographene ( NG ) - that are photoactive .
 Chemical: zinc phthalocyanine; Chemical: zinc phthalocyanine; Chemical: oPPV; Chemical: graphite; Chemical: graphene
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: zinc phthalocyanine; Chemical: zinc phthalocyanine; Chemical: oPPV; Chemical: graphite; Chemical: graphene