Chromene compound

A chromene compound having a skeleton represented by the following formula (1):

• wherein R3 is a sulfur-containing substituent selected from the group consisting of thiol group, alkylthio group, alkoxyalkylthio group, haloalkylthio group, cycloalkylthio group, arylthio group, heteroarylthio group, alkylsulfonyl group, alkoxyalkylsulfonyl group, haloalkylsulfonyl group cycloalkylsulfonyl group, arylsulfonyl group, heteroarylsulfonyl group, hydroxysulfonyl group, alkylsulfinyl group, alkoxyalkylsulfinyl group, haloalkylsulfinyl group, cycloalkylsulfinyl group, arylsulfinyl group, heteroarylsulfinyl group and hydroxysulfinyl group, and a combination of R1 and R2 is selected from the following (i) to (v):
• (i) R1 is an aryl group or a heteroaryl group, and R2 is an electron donating group having a Hammett constant σp of −0.1 or less;
• (ii) R1 is an electron donating group having a Hammett constant σp of −0.1 or less, and R2 is an aryl group or a heteroaryl group;
• (iii) R1 and R2 are each a sulfur-containing substituent selected from the group consisting of thiol group, alkylthio group, alkoxyalkylthio group, haloalkylthio group, cycloalkylthio group, arylthio group and heteroarylthio group;
• (iv) R1 is the sulfur-containing substituent, and R2 is a hydrogen atom, hydroxyl group, alkyl group, haloalkyl group, cycloalkyl group, alkoxy group, amino group, heterocyclic group having a ring member nitrogen atom and bonded to a 7-position carbon atom via the nitrogen atom, cyano group, nitro group, formyl group, hydroxycarbonyl group, alkylcarbonyl group, alkoxycarbonyl group, halogen atom, aralkyl group, aralkoxy group, aryloxy group or aryl group;
• and
• (v) R1 is a hydrogen atom, hydroxyl group, alkyl group, haloalkyl group, cycloalkyl group, alkoxy group, amino group, aliphatic heterocyclic group having a ring member nitrogen atom and bonded to a 6-position carbon atom via the nitrogen atom, cyano group, nitro group, formyl group, hydroxycarbonyl group, alkylcarbonyl group, alkoxycarbonyl group, halogen atom, aralkyl group, aralkoxy group or aryloxy group, and R2 is the sulfur-containing substituent.