Crystal Structure of o-Carboxyphenylfluorone as a Multifunctional Dye

The crystal structure of o-carboxyphenylfluorone (denoted OCPF) was determined by X-ray diffraction. This compound crystallizes in triclinic, space group P1 with a = 8.738(2), b = 9.394(2), c = 11.712(2)Å, α = 107.747(3)°, β = 93.435(3)°, γ = 91.447(3)°, V = 913.0(3)Å3, Z = 2. The final R value is 0.0730. The structure takes a dihedral formation consisting of xanthene and benzene carboxylic rings and tautomers. They exist with a zwitterionic character; the dihedral angle between the xanthene and benzene rings systems is 69.22(5)°, and the end of the rings of xanthene are inclined to each other at an angle of about 6.6(1)°.