Heteroatom-Connected Ferrocenyl BODIPYs: Synthesis, Structure, and Properties

The
set of heteroatom-connected ferrocenyl BODIPYs 2a,b and 3c,d were designed and synthesized
by the nucleophilic aromatic substitution reaction of 8-chloro BODIPY 1, with ferrocenyl anilines and ferrocenyl phenols. The effects
of a heteroatom at the meso position on the optical
and electrochemical properties of the BODIPYs were studied. The absorption
spectra of the BODIPYs containing an N atom at the meso position (2a,b) show a blue shift of 80
nm, whereas the BODIPYs containing an O atom at the meso position (3c,d) show a blue shift of 50
nm in comparison to 8-chloro BODIPY (1). The DFT calculations
reveal strong donor–acceptor interactions. The nature of the
heteroatom does not affect the HOMO but perturbs the LUMO. The single-crystal
X-ray structures of 2a,b and 3c,d show interesting supramolecular interactions. The
crystal structure of 2a shows two molecules in an asymmetric
unit arranged into a complex 3D structural motif, 2b contains
a staircase-shaped arrangement of tetramers to form a 2D structural
sheet, 3c forms a sheet in a zigzag manner, and 3d forms a sheet which contains alternating bands of ferrocenyl
and BODIPY units.