Herbert Walter Roesky (6.11.1935–5.12.2025): One Who Set Out to Learn Chemistry

Warmed by the first spring sunshine and deep in conversation, we soon found ourselves on a hilly hiking trail that led to a beautiful excursion restaurant—an ideal spot to treat ourselves to a bacchanalian break. The sun's rays sparkled in two glasses of white burgundy wine standing before us on the table. We were delightfully slowed down. ‘In the old days, we would have got up the mountain faster.’ I added with a laugh, ‘Well, come on, at least we made it.’ As we gazed at the spectacular view of the Vosges, our eyes also drifted back in time; nothing unusual for two men in their mid-sixties. “I keep thinking of Herbert Roesky. He was my wonderful teacher and mentor, a tirelessly curious man. He remained incredibly fit well into old age and came to the Göttingen institute every day, either by bicycle or on foot”. I added, ‘Yes, he is missed. And that we no longer read anything by him.’ Then, laughing out loud, ‘True, one is tempted to ask in his style: Roesky, where are you hiding? (Wo stecken Sie?)’ And after a brief silence, ‘That's exactly what he once wrote to me in his unmistakable, razor-sharp handwriting during one of his daily rounds through the lab, in my laboratory notebook. The “Old Man”, as we called him, was always eager to learn what was new in the laboratory and loved doing his morning rounds. He was boundlessly curious.’ ‘Let's drink to his memory.’ ‘Since we don't really know where he is now, tell me, do you know where he came from?’ Not much is known about his youth. He was born on 6 November 1935 in Laukischken in East Prussia (today Saranskoje, east of Kaliningrad in Russia). One can only vaguely imagine the hardships and deprivations the Roesky family endured as they fled more than 1000 kilometres west to Seesen amid the turmoil of the second world war. It was certainly a formative time for Herbert Roesky. His father, Otto Roesky, and his wife Lina ran a dairy in Laukischken and, after fleeing, worked in a dairy in the Harz region. There Herbert attended school and passed his high school exam in 1956. He then began an apprenticeship as a dairy specialist, which probably quickly exhausted his curiosity. He subsequently enrolled at the Georg-August University in Göttingen, where he completed his doctorate in 1963 in the group of Oskar Glemser with a thesis on the attempted synthesis of CrF6. The results were published in Angewandte Chemie in 1963—by the way, the first of nearly 200 papers he published in this journal during his more than 60 year publishing career. He was extraordinarily creative and productive, publishing over 1250 papers that have been cited more than 41 000 times. His curiosity, manual dexterity and determination quickly put him on the fast track to discovering new chemical territories. As a postdoctoral researcher in the group of Earl Muetterties at DuPont Central Research Department, his own scientific journey rapidly gained momentum. There he began to work intensively on the molecular chemistry of sulphur–phosphorus compounds—two of his favourite elements, as he liked to emphasise. The syntheses had to be carried out on a larger scale, because Herbert Roesky liked to say with a smile that a compound on the milligram scale does not really exist. He then returned to Göttingen and completed his habilitation in 1967 with a thesis on substituted phosphates. Amusing stories circulated about the Herbert Roesky of that time. Legendary, for example, were the battles fought at night in the institute with fire extinguishers in his small research group. Hard to imagine when one later met the gentlemanly Roesky. ‘You know, he did celebrate, but he was thoroughly disciplined. The days started early, especially when he was meticulously preparing his large experimental lecture, which often attracted up to 1 000 listeners’. From this, a special passion developed, and Herbert Roesky toured Europe with specially made equipment to present chemical experiments and witty quotations related to them. The lectures became legendary and enthralled both expert audiences and laypeople alike. Many of the experiments found their way into the fascinating book ‘Chemische Kabinettstücke’ (‘Chemical Showpieces’), which he published together with Klaus Möckel. Not least because of their popularity, his didactically brilliant books were honoured with a literature prize from the Fonds der Chemischen Industrie. But back to what happened in the laboratory: ‘I can tell you, we experimented like there was no tomorrow. From Frankfurt, where he taught and researched from 1971 alongside Hans Bock at the Institute of Inorganic Chemistry, he brought with him in 1980—when he returned as full professor to his beloved alma mater, the Georg August University of Göttingen—the chemistry of cyclic sulphur–nitrogen compounds. Not entirely harmless—because S4N4 became one of his household reagents.’ By chance, one of his doctoral students discovered the first conjugated metal–nitrogen–sulfur compound (in milligram quantities) while subliming an otherwise completely useless black-brown residue (a ‘Schlunz,’ as Herbert Roesky liked to call it). ‘Sublime it’ was a piece of advice often heard from him when a substance stubbornly refused to dissolve. A cornucopia of results emerged, unusual classes of substances were discovered, and the research group quickly grew. Every Friday afternoon the laboratory was tidied, reaction vessels cleaned, and new experiments set up. In this way, completely unexpected results were often achieved, which caused new research topics to spring up like mushrooms. This was also the birthplace of sensational substance classes such as the metallaphosphazenes or crystalline coordination polymers. The taming of aluminium and titanium fluorides, which had previously stubbornly resisted crystallisation, was also achieved. Among them were compounds that are now used as additives to increase the efficiency of catalysts in polymerisation chemistry. The congenial collaboration between the Roesky group and the grand master of crystallography in Göttingen, George Sheldrick, revealed many structural details of the inorganic compounds from Roesky's kitchen. Herbert Roesky was a wonderful and very popular host; he promoted and enjoyed a wide-ranging exchange with visiting professors and international students. His tireless activities and conceptual curiosity, which encompassed almost the entire periodic table, stopped at practically no chemical element. He was also happy to be inspired by published work from other groups and expanded the chemical space through more elegant synthetic procedures with higher yields. Reproducibility of results and resource conservation were important to him: if the yield was too meagre, he had the experimental protocols checked by his doctoral students, which led to new synthetic procedures and made substances available in much larger quantities. His work was admired worldwide and honoured with numerous prizes and honorary doctorates, including the Gottfried Wilhelm Leibniz Prize, the Alfred Stock Memorial Prize and the Wilkinson Prize. He was especially fond of his honorary memberships in France and India. Also noteworthy are the Wacker Silicone Award (2018) and the Frederic Stanley Kipping Award of the American Chemical Society (2024), awarded 14 and 20 years, respectively, after his retirement. Even long after he became emeritus, the molecular chemistry of Herbert Roesky continued to produce textbook knowledge. Low-valent aluminium and silicon compounds were particularly close to his heart. With chemical breakthroughs such as the synthesis of isolable chlorosilylenes—for example, an N-heterocyclic carbene complex of dichlorosilylene and chloroamidinatosilylenes—he threw the door wide open to new functional groups in main-group chemistry. With the synthesis of the first isolable aluminylene, which contains a two-coordinate Al(I) atom in the coordination sphere of a β-diketiminato ligand, he also provided the scientific community with a versatile new synthetic building block whose reactivity continues to cause a sensation to this day. In addition to his research, he also found time for his alma mater; from 2002 to 2008 he was President of the Academy of Sciences in Göttingen. Whatever else, Herbert Roesky remained a down-to-earth, modest man. He loved simple food. Nothing beat warm, fresh yeast pastry and a good white wine. “He would certainly have liked to sit here with us, and over wine and pastries we would have given birth to a new research idea.” For Herbert Roesky, actions spoke louder than words. He was not a man of grand speeches. Wherever he could, he supported young talents in an unselfish way. Everyone who came to him was given a chance. When, towards the end of his career—which lasted almost until his last day—public funding dried up, he did not hesitate to finance his research from his own pocket. This achievement of Herbert Roesky cannot be praised enough, for it sprang from the deeply felt conviction that science is a passionate vocation, far more than just a profession. “Speaking of passion and empathy: did you know that he initiated a fundraising campaign for a military hospital in Lviv in Ukraine at the Berlin-Brandenburg Academy of Sciences and donated generously himself? A real doer. And he endowed a prize in honour of his wife Christel—the ‘Christel and Herbert Roesky Prize’, which is awarded every two years by the German Chemical Society for outstanding achievements in molecular main-group chemistry.” Herbert Roesky has left a lasting mark on a large scientific community. We look out over the spring landscape and remain silent for a while. ‘Gratitude helps,’ I say, ‘to overcome melancholy. Even if we don't know exactly where he is now, a piece of his creative power lives on in every member of his large scientific family.’ We refill our glasses and raise them to his memory in deep gratitude and connection: ‘Cheers, Herbert!’ Hansjörg Grützmacher (ETH Zürich and Sun Yat Sen University) and Matthias Driess (Technical University of Berlin) The English translations have been performed with the help of GROK.