In memory of Professor Ugo Mazzucato (1929–2017)

This special issue is in memory of Professor Ugo Mazzucato, who passed away on 15^th October 2017, and it is dedicated to his main scientific interests in the field of photochemistry and photophysics.

Born in Padua in 1929, Ugo Mazzucato received his “laurea” degree from the University of Padua where he was lecturer and assistant professor in Physical Chemistry for 12 years (1955–1968). Then, he moved to the University of L'Aquila as Professor of General Chemistry (1968–1970) and finally he was Chair in Physical Chemistry at the University of Perugia (1970–2005). After retiring in 2005, he was appointed as a Professor Emeritus by the Academic Authorities of Perugia. In this role he continued his scientific activities until just a few weeks before passing away.

Exceptional researcher and teacher, he was for us a mentor along our scientific and academic path, as his students first and then ourselves as teachers, transferring on to us his great passion for the research work and scientific rigour. His most beloved research interest was focused on the processes of rotation around double bonds (cis–trans photoisomerization) and single bonds (ground-state rotamerism) in stilbene-like compounds and their heteroanalogues. However, among the more than 220 scientific papers written by Professor Mazzucato, some also concern studies of kinetics, spectroscopy, acid-base equilibria, charge transfer processes, photographic sciences and themes related to chemical education. His interest in photochemistry was also devoted to the investigation of photoinduced bimolecular processes with energy, electron and proton donors or acceptors, photo- and acid-chromic systems, organic scintillators, the effect of light on drugs and, more recently, non-linear optics properties of push–pull compounds.

He organized, first in Padua and later in Perugia, a modern photochemistry and organic photophysics laboratory, equipped with conventional stationary techniques and rapid pulsed techniques for the study of transient species in absorption and in emission (now up to fs resolution).

Very friendly in the human relationships and much appreciated by the international scientific community, Ugo Mazzucato established many scientific collaborations and developed projects with important photophysical laboratories, such aas the Department of Physics of Manchester (J. B. Birks), the Chemistry Division of CNR of Ottawa (W. Siebrand), the Weizmann Institute of Rehovot (E. Fischer) and the Max-Planck-Institut fur Strahlenchemie of Muelheim (H. Goerner, D. Schulte-Frohlinde). In the field of photochromism collaborations were carried out with the “Université de la Méditerranée” of Marseille (R. Guglielmetti, A. Samat), the University of Lille (G. Vermeersch, S. Delbaere), the “Instituto de Tecnologia Quìmica e Biològica”, Oeiras (R. S. Becker) and the Center for Photochemical Sciences of the Bowling Green State University, Ohio (M. A. J. Rodgers). He also participated, as associate member of the INFN of Perugia (1991–2001), in an international collaboration (Borexino) on the study of solar neutrinos, with particular attention at the optical properties of the scintillator mixture used for their detection.

Professor Mazzucato was a member of several Councils of important research centers in Italy, such as the Scientific Councils of the Center of Photochemistry of the CNR of Ferrara (1973–1987), of the Laboratory of Photochemistry and High Energy Radiation (FRAE, now ISOF) of the CNR of Bologna (1969–2001, from 1978 to 2001 as President) and of the Center of Physical Chemical Studies on the Light Material Interaction of the CNR of Bari (1998–2001, as President).

He actively participated in the working group that founded the European Photochemistry Association (1970) and he had been a member of the standing committee for two terms. At national level, he was one of the founding members (of which he held the position of president) of the Italian Photochemistry Group, the National Divisions of Physical Chemistry and Chemical Education and the Umbrian section of the Italian Chemical Society. Our sincere thanks go to his friends and colleagues for having accepted the invitation to write a scientific work to contribute to this special issue and to the reviewers and editorial office for their collaboration.

Finally, we would like once more to express our deep and special gratitude to our beloved Professor Mazzucato because his behaviour, rectitude and kindness were for all of us not only a guide in the scientific research but also in our daily life.

“It is true that the light of science illuminates the world, but it is equally true that it is a dry light, in itself insufficient to the multiple needs of the human soul” (J. Tyndall)

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