Abstract
The synthesis, electrochemistry and photophysical characterization of a 10,10-
dimethylbiladiene tetrapyrrole bearing ancillary pentafluorophenyl groups at the 5 and
15-meso positions (DMBil1) is presented. This non-macrocyclic tetrapyrrole platform is
robust and can serve as an excellent ligand scaffold for Zn2+ and Cu2+ centers. X-ray
diffraction studies conducted for DMBil1 along with the corresponding Zn[DMBil1] and
Cu[DMBil1] complexes show that this ligand scaffold binds a single metal ion within the
tetrapyrrole core. Additionally, electrochemical experiments revealed that all three of the
aforementioned compounds display an interesting redox chemistry, as the DMBil1
framework can be both oxidized and reduced by two electrons. Spectroscopic and
photophysical experiments carried out for DMBil1, Zn[DMBil1] and Cu[DMBil1] provide
a basic picture of the electronic properties of these platforms. All three biladiene
derivatives strongly absorb light in the visible region and are weakly emissive. The
ability of these compounds to sensitize the formation of 1O2 at wavelengths longer than
500 nm was probed. Both the freebase and Zn2+ 10,10-dimethylbiladiene architectures
show modest efficiencies for 1O2 sensitization. The combination of structural,
electrochemical and photophysical data detailed herein, provides a basis for the design
of additional biladiene constructs for the activation of O2 and other small molecules.
