Synthesis, Redox Properties, and Electronic Coupling in the Diferrocene Aza-dipyrromethene and azaBODIPY Donor–Acceptor Dyad with Direct Ferrocene−α-Pyrrole Bond

3,3′-Diferrocenylazadipyrromethene
(3) and
corresponding difluoroboryl (azaBODIPY) complex (4) were
synthesized in several steps from ferrocenecarbaldehyde, following
the well-explored chalcone-type synthetic approach. The novel diiron
complexes, in which ferrocene groups are directly connected to the
α-pyrrolic positions were characterized by a variety of spectroscopic
techniques, electrochemistry, spectroelectrochemistry, and X-ray crystallography,
while their electronic structure, redox properties, and UV–vis
spectra were correlated with the density functional theory (DFT) and
time-dependent DFT calculations.