title: Synthesis, characterization and structural investigation of novel meso-pyridyl BODIPY-cobaloxime complexes.
abstract: We report the synthesis of four boron-dipyrromethene (BODIPY) sensitized cobaloxime complexes as structural models of light-driven proton reduction catalysts. The BODIPY chromophore is covalently linked to the cobaloxime via a pyridine molecule in the meso-position of the BODIPY. Electron withdrawing or donating substituents on the pyridine (e.g. chloro- or methyl-groups) allow a comparison of the influence of these substituents on cobaloxime-BODIPY interactions. This includes altering the overall stability of the complexes and tuning the catalytically relevant Co(II/III) redox couple over a range of 220 mV, which will assist in the design of future cobaloxime-chromophore complexes. All complexes were characterized using electrochemistry, electronic absorption and fluorescence spectroscopy. Additionally, we present crystal structures of the four new BODIPY-cobaloxime complexes and elucidate the influence of the structural modifications. We found that these compounds produce sub-stoichiometric quantities of hydrogen under standard photon-driven hydrogen evolving conditions.
authors.affiliation: North Carolina State University, 2620 Yarborough Drive, Campus Box 8204, Raleigh, NC 27695-8204, USA. wwweare@ncsu.edu.
authors.forename: Juergen
authors.initials: J
authors.lastname: Bartelmess
authors.forename: Walter W
authors.initials: WW
authors.lastname: Weare
authors.forename: Roger D
authors.initials: RD
authors.lastname: Sommer