Obituary for Siegfried Hünig

Siegfried Hünig studied chemistry at the Technical University of Dresden from 1939 to 1942. In 1943, he earned his doctorate under Wolfgang Langenbeck with studies on the condensation of acetaldehyde and crotonaldehyde, and was henceforth allowed to use the title “Doctoral Engineer”.

He stayed in Dresden for another two years as a research assistant, yet under increasingly difficult conditions. These culminated in devastating air raids in February 1945, which destroyed great part of Dresden and also severely damaged the university buildings. This prompted Hünig and his pregnant wife to leave their beloved homeland after the end of the war.

Via Lower Franconia, Hünig came to the Institute of Chemistry at the University of Marburg, where he worked with Hans Meerwein as a scientific assistant from 1946 onwards. In 1950, he completed his habilitation in chemistry with a thesis "On the catalytic condensation of crotonaldehyde with secondary amines in the absence of acid" and received the Venia Legendi. After six years as a senior assistant in Marburg, Hünig was appointed assistant professor in May 1956.

In 1958 and 1959 he went on research trips through the USA where he worked at the University of California in Los Angeles, together with Saul Winstein and Donald J. Cram. In November 1960, he was appointed extraordinary professor of organic chemistry at the Faculty of Natural Sciences at the University of Munich.
 

The Würzburg Years

Just one year later, on November 1, 1961, Hünig became full professor of chemistry at the University of Würzburg and director of the Chemistry Institute located in a building at Röntgenring, which had been planned by Nobel laureate Emil Fischer. After getting to know the advantages of modern university structures, especially in the USA, Hünig with great commitment and foresight pursued a restructuring of the long-established institute into today's Institutes of Inorganic and Organic Chemistry. He was also in charge of designing the new chemistry center on the outskirts of Würzburg. From 1965 on, he was director of the newly founded Institute of Organic Chemistry and Chair of Organic Chemistry I. In 1969, he was able to move into the first of the ultra-modern new buildings at the Hubland Chemistry Center.

In 1974 the Faculty of Mathematics and Natural Sciences was divided into departments, which finally led to the transformation into independent Faculties in 1979. In these challenging times of change, Hünig served as Dean of the newly founded Faculty of Chemistry and Pharmacy from 1979 to 1981. In the two years before and after that he was vice Dean. At the end of the summer semester 1987, Hünig retired, much earlier than usual, to ensure that his chair would be handed over to his favorite successor, Gerhard Bringmann. Over the years and even after his retirement, Hünig has repeatedly visited Universities abroad as a visiting professor e.g. in the USA, Israel, Brazil, South Africa and Hong Kong.
 

Teaching – dedication instead of duty

Teaching was a heartfelt passion to Hünig. Not just the training of advanced students and potential research assistants, but also for the first-year students in chemistry and other natural sciences subjects. Therefore, he gave the lecture Experimental Chemistry II (Organic Chemistry) with joy and great personal commitment, but also a non-curricular lecture "Studying natural sciences - but how?" with illustrative demonstrations that should train scientific thinking and working. In addition, he established a tightly organized and analytically shaped internship concept, which is reflected in the textbook "Integrated Organic Laboratory Course" (by Hünig, Märkl and Sauer) and, together with other measures initiated by him, contributed significantly to the short study times up to the chemistry diploma, compared to the average study duration in West Germany.
 

Scientific work - much more than just the Hünig base

Every (organic) chemist will probably know the Hünig base: diisopropylethylamine, a sterically hindered tertiary amine with very low nucleophilicity, which Hünig first reported on its potential for use in 1958. Few, however, may be aware of how diverse and creative Hünig was as a chemist and how many foundations he laid for research areas that even today are often highly topical. An excellent summary has been published recently in the form of an essay by Hans-Ulrich Reißig in the journal Angewandte Chemie. For this reason, Hünig's contributions to (physical) Organic Chemistry will only be mentioned briefly here:

• Use of sterically hindered amines as bases in organic synthesis
• Aldol condensation and Diels-Alder reactions of electron-rich dienes
• Enamines as building blocks for synthesis, acylation of enamines
• Diimine as a reagent for chemoselective reduction of double bonds
• Synthesis, properties and reactions of polycyclic systems with parallel C = C and N = N double bonds
• Regio-, diastereo- and enantioselective protonation reactions
• Redox Umpolung with trialkylsilyl cyanides
• Oxidative coupling for the synthesis of heterocyclic azo dyes
• Multi-stage redox systems and redox-active cyclophanes
• Solvatochromism and electrochromism
• Organic metals

After retiring, Hünig continuously devoted himself to chemistry for many years, but later increasingly to a medical problem that personally affected him severely: age-related macular degeneration (AMD). Here, he researched the specialist literature with great meticulousness and published articles and writings on the avoidance of visual damage that were understandable for a broad audience.
 

Heroe of Chemistry and Honorary Senator

The journal "Angewandte Chemie" dedicated a website to Siegfried Hünig in March 2021, shortly before his 100th birthday, under the heading Heroes of Chemistry and Nobel Laureates. At the same time, the above-mentioned essay A homage to Siegfried Hünig and his research was published.

Hünig received the following prizes (selection):

• Adolf von Baeyer Memorial Medal, Gesellschaft Deutscher Chemiker
• Great Seal of the University of Padua
• Max Lüthi Medal, Swiss Chemical Society
• Heyrovský Medal of the Academy of Sciences of the Czech Republic

Siegfried Hünig was a member of the Bavarian Academy of Sciences and a member of the German National Academy of Sciences Leopoldina. He received honorary doctorates from the Universities in Marburg, Munich and Halle.

In recognition of his services to University of Würzburg, Hünig was awarded Honorary Senator in 2011. In the same year, the Siegfried Hünig Lecture was established on the occasion of his 90th birthday. In this context, an internationally renowned chemist is invited to give a lecture in Würzburg every year. Until 2018, Hünig was still able to participate personally, to the delight and honor of the organizers, the award winner and the auditorium.
 

Siegried Hünig as a role model

The Institute for Organic Chemistry is forever grateful to its founder, Siegfried Hünig, for setting the right course with foresight and courage more than 50 years ago, by willingly sharing his power as director of the long-established Chemistry Institute with others. The Faculty of Chemistry and Pharmacy is also deeply indebted to him, as he is considered the father of the chemistry center at Hubland, where successful research has been carried out for over 50 years and great successes have been achieved in the training of students and young scientists. Special thanks are due to him for his review of the history of chemistry in Würzburg, to which he contributed so much, long after his retirement.

Siegfried Hünig is undoubtedly one of the great chemists of the second half of the 20th century and one of the great professors in the long history of the University of Würzburg. A great man and role model who has taken on responsibility and leadership and has always remained approachable and emphatic has passed away.

The institute’s management board, professors, employees as well as former colleagues and students will always keep an honorable memory of him.