4,4-Difluoro-2,3;5,6-bis(tetramethylene)-4-bora-3a,4a-diaza-s-indacene (LD540)

The title compound, C18H21BF2N2, is a lipophilic dye based on a BODIPY fluorophore backbone, which was developed for microscopic imaging of lipid droplets; the molecule has a planar BODIPY core [dihedral angle between the pyrrole rings = 2.3 (3)] and two tetramethylene substituents at the 2,3- and 5,6-positions in a half-chair conformation. One of the tetramethylene substituents is disordered over two two sets of sites with site occupancies of 0.5. In the crystal, pairs of C— HF interactions link the molecules into inversion dimers. Neighbouring dimers are linked by further C—HF interactions, forming an infinite array. C—H and – [centroid–centroid distance = 4.360 (3) A˚ ] interactions are observed between the BODIPY core and the tetramethylene substituents of neighbouring dimer pairs.