It soon became obvious to them, however, that things really became interesting for me once the corn, the algae or the bacteria were crushed and their cells broken up. Since then, I was a farmer of baby corn to them. When I was shaving a plate of two-week-old wheat, their eyes lit up: for the first time, there was something familiar to them in the labs. The second incident was when my young children accompanied me one day to the basement at Argonne where all kinds of organisms were grown on stable isotope media. Moreover, they confessed that they hardly understood anything besides the introductory sentences. They were quite startled to see a such a tiny booklet of approximately 150 DIN A5 pages as the result of three years of work. The first was when I handed my doctoral thesis to my parents. The extent of how detached it became is illustrated by two incidents. Much of the work performed in Braunschweig, Argonne, and later on in Munich refers to photosynthesis, although this was rather detached from living organisms. Chl derivatives are used as colorants for food and cosmetics, they are also candidates for optoelectronic use. Chls also have a wealth of applications : in basic science, modified pigments allow for functional analyses in medicine, they serve as photosensitizers. Besides their involvement in primary charge separation in the reaction center, they serve as light-harvesting and light-sensing pigments, they also have additional functions, e.g., in inter-system electron transfer. They provide the basis for photosynthesis and thereby most life on Earth, in addition to several other functions. It provided the basis for studying, over the next 45 years, several aspects of this group of molecules under many guises. This time as an apprentice solidified my passion in Chls and subsequently to open-chain tetrapyrroles. When we discussed his ideas of a “special pair” of Chls as the primary donor in photosynthesis, I remembered a selective deuteration from the Braunschweig lab that was key to proving the proposal by using Jim’s advanced electron double resonance tools. I was lucky to have Jim Norris as a challenging guide. His group was famous for using the stable isotopes, 2H and 13C, for studying chlorophyll interactions in the test tube and in photosynthetic organisms. As a postdoctoral researcher, I went to Joe Katz at Argonne National Laboratory. Additionally, the spectroscopic tools available in Braunschweig, particularly circular dichroism and nuclear magnetic resonance, proved invaluable in analyzing the structure, including the stereochemistry, of the dozens of derivatives “cooked” from this material. The “Phäophytin Sandoz”, a mixture of (mainly) pheophytins a and b dating back from the time of Arthur Stoll with Sandoz, proved an invaluable supply for making chemical modifications of the basic skeleton of chlorophyll a: after the first bottle ran out, it was replaced by another one and subsequently by a third one. Herbert Wolf, one of the sous-chefs, had proposed using the Chl-macrocycle as a platform for studying the stereochemistry of side-chains for a diploma and later doctoral degree. Chlorophyll (Chl) first came to me in a bottle containing approximately 1 kg of “Phäophytin Sandoz”, handed over by Hans-Herloff Inhoffen, the big boss of organic chemistry at the Technical University of Braunschweig.
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