title: Synthesis of new photosensitive H2BBQ2+[ZnCl4]2-/[(ZnCl)2(μ-BBH)] complexes, through selective oxidation of H2O to H2O2.
abstract: A new two-electron photosensitizer, H2BBQ2+[ZnCl4]2-/[(ZnCl)2(μ-BBH)] (BBQ stands for 2,5-bis[bis(pyridin-2-ylmethyl)amino]-1,4-quinone and BBH stands for 2,5-bis[bis(pyridin-2-ylmethyl)amino]-1,4-hydroquinone), has been synthesized and the oxidation state of the ligand was determined by X-ray crystallography and NMR spectroscopy. Under light illumination the H2BBQ2+[ZnCl4]2-+ ZnCl2is reduced quantitatively to [(ZnCl)2(μ-BBH)] (pH ∼ 5) oxidizing H2O to H2O2as is evident by trap experiments. Electrochemistry gave a reversible two-electron ligand-centered redox wave for [(ZnCl)2(μ-BBH)]. UV-Vis, luminescence and EPR spectroscopies reveal the slow formation of a stable quinone diradical, intermediate of the reaction. DFT calculations are in agreement with the proposed mechanism. Based on this property an aqueous {[(ZnCl)2(μ-BBH)]||H2O2} solar rechargeable galvanic cell has been constructed.
authors.affiliation: Department of Chemistry, University of Cyprus, Nicosia 1678, Cyprus. akeramid@ucy.ac.cy shayes@ucy.ac.cy and Department of Agricultural Production Biotechnology and Food Science, Cyprus University of Technology, Limassol 3036, Cyprus. chryssoula.drouza@cut.ac.cy.
authors.forename: M
authors.initials: M
authors.lastname: Stylianou
authors.affiliation: Department of Chemistry, University of Cyprus, Nicosia 1678, Cyprus. akeramid@ucy.ac.cy shayes@ucy.ac.cy.
authors.forename: I
authors.initials: I
authors.lastname: Hadjiadamou
authors.affiliation: Department of Agricultural Production Biotechnology and Food Science, Cyprus University of Technology, Limassol 3036, Cyprus. chryssoula.drouza@cut.ac.cy.
authors.forename: C
authors.initials: C
authors.lastname: Drouza
authors.affiliation: Department of Chemistry, University of Cyprus, Nicosia 1678, Cyprus. akeramid@ucy.ac.cy shayes@ucy.ac.cy.
authors.forename: S C
authors.initials: SC
authors.lastname: Hayes
authors.affiliation: Department of Chemistry, University of Cyprus, Nicosia 1678, Cyprus. akeramid@ucy.ac.cy shayes@ucy.ac.cy.
authors.forename: E
authors.initials: E
authors.lastname: Lariou
authors.affiliation: Department of Chemical Engineering, University of Patras, 26500 Patras, Greece. lianos@upatras.gr.
authors.forename: I
authors.initials: I
authors.lastname: Tantis
authors.affiliation: Department of Chemical Engineering, University of Patras, 26500 Patras, Greece. lianos@upatras.gr.
authors.forename: P
authors.initials: P
authors.lastname: Lianos
authors.affiliation: Laboratory of Inorganic and General Chemistry, University of Ioannina, 45110 Ioannina, Greece. attsipis@uoi.gr.
authors.forename: A C
authors.initials: AC
authors.lastname: Tsipis
authors.affiliation: Department of Chemistry, University of Cyprus, Nicosia 1678, Cyprus. akeramid@ucy.ac.cy shayes@ucy.ac.cy.
authors.forename: A D
authors.identifier: http://orcid.org/0000-0002-0446-8220
authors.initials: AD
authors.lastname: Keramidas