A compound represented by the formula (I) (R
1
represents hydrogen atom or a monovalent substituent; R
2
and R
3
represent hydrogen atom, an alkyl group, or a halogen atom; R
4
and R
5
represent an alkyl group or an aryl group; R
6
and R
7
represent hydrogen atom, an alkyl group, or a halogen atom; R
8
represent hydroxy group or a dialkoxyboranetriyl group; and X represents silicon atom, germanium atom, or tin atom), which is a novel fluorophore usable as a mother nucleus of an off/on type fluorescent probe not utilizing the intramolecular photoinduced electron transfer.
A compound represented by the formula (I) (one of substituents represented by R1 is a trapping group for an object substance for measurement; R2 and R3 represent hydrogen, alkyl, or halogen; R4 and R5 represent alkyl or aryl; R6 and R7 represent hydrogen, alkyl, or halogen; R8 represents hydrogen, alkylcarbonyl, or alkylcarbonyloxymethyl, and X represents silicon, germanium, or tin, which can be used as a fluorescent probe that enables red color bioimaging using intramolecular photoinduced electron transfer.