In celebration of the 70thbirthday of Peter Klüfers

Abstract

Peter Klüfers, Professor emeritus at the Department of Chemistry of the Ludwig Maximilians University Munich (LMU), Germany, celebrates his 70th birthday on April 18th 2021. Friends and colleagues as well as the publisher and editors of Zeitschrift für Anorganische and Allgemeine Chemie (ZAAC) congratulate him cordially on this special occasion and dedicated this cluster issue of ZAAC to him in recognition of his scientific achievements and contribution in the field of inorganic chemistry – especially in coordination chemistry of the transition metals – but also his dedication to teaching and his willingness to contribute to the scientific community in general. Peter Klüfers was born in Uerdingen (Krefeld) in 1951, a small town at the river Rhein located between Duisburg and Düsseldorf. After grammar school, he studied chemistry at the University of Cologne, where he did his Diploma work with Prof. Dr. H.-U. Schuster in 1974. For the PhD he stayed in the same group and worked on the topic “Kristallchemische Untersuchungen an ternären Phosphiden und Arseniden mit CaAl2Si2 – oder verwandter Struktur”, which he finished in 1978. Thus, his scientific background started in the field of solid-state inorganic chemistry with a focus on X-ray structure analysis. This expertise accompanied him throughout is entire scientific life and he was always willing to share it with others. For his habilitation Peter continued to stay in Cologne on a scientific assistant position, but his focus shifted to the coordination chemistry and biological aspects in this field. To get a deeper insight into this topic, he studied pharmacy at the University of Bonn (1981–1983), which he finished with the “2. Abschnitt des Pharmazeutischen Staatsexamens” in 1983. In the same year, he finished his habilitation at the University of Cologne with the Habilitationsschrift “Kristallchemische Untersuchungen an Tetracarbonylcobaltaten einwertiger Metalle”, thus combining his interests for structural chemistry and coordination chemistry. In 1986/87 Peter did an unusual step for an ongoing university professor by deciding to work for the company Enka AG in Wuppertal (now Akzo Polymers and Fibres, Membrana). Here he learned the practical aspects of (bioinorganic) chemistry by developing copper silk membranes based on cellulose. Here his interest in metal complexes of carbohydrates started. The side trip in industry did not last long, as in 1988 Peter was appointed as professor for inorganic chemistry at the University of Karlsruhe. This was followed by an offer for a chair position for bioinorganic and coordination chemistry at the LMU in 1998 (succession of H. Nöth). Peter's research interests were situated for long time in the field of carbohydrate metal complexes and now mainly focussed on the chemistry of metal nitrosyl complexes and fundamental questions in coordination chemistry. He enjoyed the new possibilities provided by density functional theory and related modern methods to get a deeper understanding of the bonding properties of textbook compounds. A good example is the well-known brown ring complex [Fe(NO)(H2O)5]2+ that everyone knows from the first years in inorganic chemistry lab courses, where it is used to proof the presence of nitrate. In 2019 Peters group succeeded to solve the first X-ray crystal structure of this complex.1 There, he did investigate in detail the difficulties arising for the assignment of oxidation states of the covalently bound non-innocent ligand nitric oxide. In a follow up work last year he questions a statement made by IUPAC and found in many textbooks that the geometry of the M(NO) segment can be used to to assign oxidations states of such ligands.2 Next to the correct description of the bonding conditions in such complexes, the photoinduced linkage isomerism (PLI) was another area of research, which Peter successfully followed over the years. Another “textbook” question addressed by Peter's group by the combination of X-ray structure analysis and DFT calculations are unexpected coordination spheres, such as square planar iron(II) complexes stabilised by weak field diolato ligands. Reason for the unexpected structure is an unusually strong Jahn-Teller distortion of the tetrahedral arrangement.3 Further examples for Peters fascination for very fundamental questions in general inorganic, bioinorganic and coordination chemistry are the characterization of the copper complexes found in Fehling's solution and the role of carbohydrates for the transport and biomineralisation of silica. Peter Klüfers is an enthusiastic academic teacher. Over the years, more than 60 students finished their PhD in his group. For the students, he took the time to write extended scripts to accompany his lectures, which were ranked always very highly by the students who had the pleasure to listen to them. With his dedication in writing lecture scripts it is not surprising that he started writing textbooks. In 2017 the textbook “Bioanorganische Chemie. Metalloproteine, Methoden und Konzepte” appeared which he wrote together with Sonja Herres-Pawlis. This book is based on lecture scripts, which both developed. Peter Klüfers has continuously served the chemical community in numerous commissions within and outside of the LMU. He served twice as Dean of the Faculty of Chemistry and Pharmacy at the LMU Munich, was a member of the “Beirat des Mathematisch-Naturwissenschaftlichen Fakultätentages” (MNFT) and representative in the Konferenz der Fachbereiche Chemie (KFC). Here he was also very dedicated to teaching aspects, starting with chemistry school education where he compiled a catalogue of topics that should be covered. A further passion of Peter are outdoor activities such as cycling and hiking, where he could enjoy favourite spots in the Munich surrounding such as his beloved Walchensee and the near situated Jochberg. We join his colleagues, students and friends in wishing him great health and many more happy years with his family and best of success for publishing interesting and fundamental aspects in inorganic and general chemistry. The laudators: Birgit Weber, Sonja Herres-Pawlis, and Hans-Christian Böttcher. The editors: Thomas F. Fässler, Thomas M. Klapötke, Christian Limberg, and Guodong Qian.