Photochemistry

The XXVIth IUPAC Conference on Photochemistry on 3-8 April 2016 in Osaka, Japan was organized by Professor Tetsuro Majima from Osaka University, together with a large group of local organizers. They chose an impressive place to gather: the Osaka City Central Public Hall, an eye-catching building in the center of Osaka featuring pale red bricks and a bronze dome. Built as a public hall for local citizens and completed in 1918, it has become a symbol of Osaka within walking distance of the impressive Osaka Central Station as well as Osaka Castle. Approximately 600 participants from all parts of the world and all areas of photochemistry, photobiology, and photophysics met in Osaka. The conference was accompanied by a pre-symposium in Hiroshima (by Prof. Manabu Abe), two post-symposia in Kyushu and Osaka (by Prof. Yoshio Hisaeda and Prof. Hiromi Yamashita), and the 12th Korean-Japan binational symposium on “Frontier Photoscience” (KJFP-2016).

The cornerstones of this symposium were 8 plenary and 11 invited lectures, together with 291 oral presentations (including 49 young researcher and 36 student oral presentations) and 187 poster contributions. As a spectacular start to this conference, Akira Fujishima from the Tokyo University of Science, Japan, gave a talk on “Photocatalysis and CO₂ reduction”. The groundbreaking work by Honda and Fujishima on the photocatalytic activities of titanium dioxide in the second half of the last century initiated the enormous research activities in the fields of semiconductor photocatalysis, photocatalytic water splitting, and oxidation technologies in surface and water purification with an impressive potential in daily life applications. Richard A. Mathies from the University of California at Berkeley, USA, presented his results on “A coherent picture of photobiology and photochemistry,” demonstrating that vibrational dephasing and return to the lowest excited states as described by Kaska´s rule is no longer occurring for ultrafast reactions of excited states at the femtosecond time scale, such as the photoisomerization of the cis-retinal chromophore in the visual pigment rhodopsin that occurs in about 50 femtoseconds.

Thomas Carell from the University of Munich, Germany, lectured on “Time resolved IR and crystallographic studies of DNA photodamage and repair” and described the newest results on the complex mechanisms of repair processes of photoinduced DNA lesions, such as cyclobutane or 6-4 single bond lesions. He explained the differences in green plant photorepair enzymes and mammalian repair by nucleotide excision. Cornelia Bohne from the University of Victoria, Canada, gave her talk on “Mechanistic insights from supramolecular studies on the binding of guests with cucurbit[n]urils” and described a sophisticated study on rate constants of host-guest interactions of photoreponsive molecules with natural bile acids and cucurbiturils as host molecules.

Harry Anderson from Oxford University, England, presented “Excited state energy delocalization in synthetic porphyrin nanorings” where he described the synthesis of linear and cyclic oligometalloporphyrins by a template route that allowed the approach to hitherto unthinkable compounds with extended energy delocalizations in their excited singlet states. Dario M. Bassani from the University of Bordeaux, France, delivered a presentation of “A supramolecular approach to controlling the behavior of excited states” where he described the directionality and predictability of hydrogen-bonding as tool with which chromophores can be pre-oriented prior to photoexcitation in solution and in the solid. The products obtained from supramolecular photoreactions may exhibit affinity for a chosen template, thereby providing a route to substrate-induced receptor synthesis.

Can Li from the Dalian Institute of Chemical Physics, China, referred to “Photogenerated charge separation in artificial photosynthesis systems” and presented the research progress on solar fuel productions from artificial photosynthesis, namely photocatalysis and photoelectrocatalysis processes with the emphasis on the photogenerated charge separation. Nicola Armaroli from the National Research Council in Bologna, Italy, gave a talk on “Photoactive materials for energy conversion” and described the strategies to optimize the luminescence output, color and stability of Ir(III) and Cu(I) complexes, along with the possibility to switch from metal complexes to hybrid organic-inorganic materials and fully organic triplet luminophores.

The next IUPAC conferences on photochemistry will be organized in Dublin, Ireland in July 2018 by Prof. Miguel Garcia-Garibay, and in Amsterdam, The Netherlands, in July 2020 by Prof. Fred Brouwer. This conference series is alternating in odd years with the “International Conference on Photochemistry (ICP),” organized in 2017 in Strasbourg. These two conference series are clearly the path makers of international research in photochemistry and will be more strongly linked in the future in order to make this structure a more powerful stage for the exchange of research results and a tool to foster this important area in the natural sciences.