Preface for special issue of ICPOC-25 in Hiroshima

The IUPAC sponsored biennial Conference on Physical Organic Chemistry (ICPOC) series bear a long history and a solid reputation as the leading international gatherings on Physical Organic Chemistry. Since their first installment in Crans sur Sierre (Switzerland) in 1972, ICPOC meetings have been held in Noordwijkerhout (The Netherlands, 1974), Montpellier (France, 1976), York (UK, 1978), Santa Cruz (USA, 1980) Louvain-la-Neuve (Belgium, 1982), Auckland (New Zealand, 1984); Tokyo (Japan, 1986), Regensburg (Germany, 1988), Haifa (Israel, 1990), Padua (Italy, 1994), Incheon (Korea, 1996), Florianopolis (Brazil, 1998), Göteborg (Sweden, 2000), San Diego (USA, 2002), Shanghai (China, 2004), Warsaw (Poland, 2006), Santiago de Compostela (Spain, 2008), Busan (Korea, 2010), Durham (UK, 2012), Ottawa (Canada, 2014), Sidney (Australia, 2016), and Faro (Portugal, 2018). The 25th IUPAC International Conference on Physical Organic Chemistry (ICPOC 25) was held at the Hiroshima City Bunka Koryu Kaikan in Hiroshima City, July 10–15, 2022. The conference was originally scheduled to be held at the Grand Prince Hotel Hiroshima in July 2020, but due to COVID-19, the year was postponed two years to 2022. ICPOC 25 expected a total of 350 participants, 100 from Japan and 250 from overseas. Despite the postponement to 2022, due to the remained impact of COVID-19, unfortunately, almost no participation from overseas was expected at the conference site. We decided to hold ICPOC-25 using the hybrid format of Onsite and Online, which allowed many distinguished invited speakers, including a Nobel laureate in chemistry, to present, enhanced the content of the international conference and increased the number of participants from Japan. From these factors, the number of participants (331, Onsite 261, which includes 44 overseas participants, and Online 70) was close to the originally planned 350. I hope that the 26th IUPAC International Conference on Physical Organic Chemistry (ICPOC 26), which will be held in August 18–23 in Beijing, will not have any impact from COVID-19.

Traditionally, Physical Organic Chemistry relates molecular structure to chemical behavior, by means of the study of structure, reactivity, mechanism and equilibrium in organic systems, aiming at the quantitative, molecular level understanding of their properties. Today, Physical Organic Chemistry encompasses a broader range of context, further expanding into materials science, biology and systems chemistry. For the organizers of ICPOC 25, the main goal has been to offer a scientific program that reflects the comprehensive and multidisciplinary approach associated to Physical Organic Chemistry and pinpoints current developments in the area, thus promoting the vibrant and enlightening scientific discussions usually held in ICPOC meetings.

The scientific program of ICPOC 25 comprised 9 plenary lectures (by Chihaya Adachi, Guy Bertland, Michelle Coote, Bernard Feringa, Makoto Fujita, Josef Michl, Julius Rebeck, Wolfram Sander, and Sason Shaik), 13 keynote lectures, 51 invited lectures and 48 oral communications, split among three parallel sessions and 96 poster presentations.

Local Organizing Committee:Manabu Abe (Hiroshima University, Chair), Takeharu Haino (Hiroshima University, Co-Chair), Sayaka Hatano (Hiroshima University), Shuhei Itoh (Chiba Institute of Technology), Daisuke Kaneno (Kochi University), Toshikazu Kitagawa (Mie University), Kazuhide Nakata (Hosei University), Yasushi Ohga (Oita University), Satoshi Usui (Niigata University)

International Advisory Committee: Ian Williams (UK, Chair), Manabu Abe (Japan), Igor Alabugin (USA), Jin-Pei Cheng (Chiana), Maria de Lurdes Cristiano (Portugal), Jason Harper (Australia), Eduardo Humeres (Brazil), Moisés Canle López (Spain), Miroslav Ludwig (Czech Republic), Anat Milo (Israel), Annmarie O’Donoghue (UK), Henrik Ottosson (Sweden), Charles Perrin (USA), Hans-Ullrich Siehl (Germany), R. B. Sunoj (India), Pietro Tundo (Italy), Einar Uggerud (Norway).

The special issue consists of 10 contributed papers, which are from research team of Shigehisa Akine (Kanazawa), Takeharu Haino (Hiroshima), Akihito Konishi (Osaka), Takashi Kubo (Osaka), Maria Paz Munoz (UK), Armin Ofial (Munich), Akihiro Shimizu (Osaka), Shih-Sheng Sun (Taipei), Yumi Yakiyama (Osaka), and Aya Yoshimura (Ehime).

Akine et al. discovered “Control of Chirality Inversion Kinetics of Triple-helical Metallocryptands”, Pure and Applied Chemistry, 2023, 95, 331–341. Haino and his coworkers clarified “Cooperativity in Molecular Recognition of Feet-to-Feet-connected Biscavitands, Pure and Applied Chemistry, 2023, 95, 343–352. Konishi presented their research on “Bis-periazulene: Remaining Non-alternant Isomer of Pyrene”, Pure and Applied Chemistry, 2023, 95, 353–362. Kubo described a topic of “Closed-shell and open-shell dual nature of singlet diradical compounds”, Pure and Applied Chemistry, 2023, 95, 363–375, in which singlet diradical character, closed-shell versus open-shell, is found to be controlled by external environment. Muñoz and her coworkers report “Anticancer Activity and DNA Interaction of Bis(pyridyl)allene-derived Metal Complexes”, in which new series of Au(III) carbene complexes were found as the novel DNA-binding metallodrugs, Pure and Applied Chemistry, 2023, 95, 377–388. A topic of “Reactivity of Electrophilic Cyclopropanes” was reported by Ofial, in which the second-order rate constants of ring-opening reaction of electrophilic cyclopropanes with strong nucleophiles were determined to clarify the reactivity of cyclopropane derivatives, Pure and Applied Chemistry, 2023, 95, 389–400. Shimizu et al. introduced “Synthesis and Properties of m-Quinodimethane-based non-Kekulé and Kekulé Fused-ring Hydrocarbons with a Triplet Ground State, Pure and Applied Chemistry, 2023, 95, 401–412. Shih-Sheng Sun reported their research on “White Light Emission from an Upconverted Emission Based on Triplet-triplet Annihilation with Rose Bengal as the Sensitizer”, Pure and Applied Chemistry, 2023, 95, 413–419. Yakiyama et al. report a topic of “Fluorosumanenes as Building Blocks for Organic Crystalline Dielectrics”, where they synthesized a newly designed fluorinated sumanene, 1,1-difluorosumanene that show a large dipole moment along the in-plane direction, Pure and Applied Chemistry, 2023, 95, 421–430. Yoshimura summarized their study on “Tetrathiafulvalene Analogs of Electrode Materials: Discovery of an in-cell polymerization technique”, Pure and Applied Chemistry, 2023, 95, 431–438.