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.