A fine particle which contains a compound represented by formula (1): wherein R1a and R1b may be the same or different, and each independently represent an alkyl group, an aryl group, or a heteroaryl group; R2 and R3 each independently represent a hydrogen atom or a substituent, and at least one of R2 and R3 is an electron withdrawing group; R2 may be bonded to R3 to form a ring; R4 represents a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, a substituted boron, or a metal atom; and R4 may be covalently bonded or coordinately bonded to at least one among R1a, R1b and R3.