Richard Willstätter

Richard Willstätter determined that chlorophyll contains a central magnesium atom within a porphyrin ring structure. He also distinguished chlorophyll-a from chlorophyll-b, showing that they are two chemically distinct compounds that differ in a single functional group on the porphyrin ring.

Willstätter received the 1915 Nobel Prize in Chemistry for his investigations of plant pigments, particularly chlorophyll. His work established the structural foundations of photosynthetic pigments and advanced understanding of how plants capture and use light energy.

As a Jewish scientist in Germany, Willstätter was forced to resign from his professorship at the University of Munich in 1935 when the Nazi regime expelled Jewish academics from universities. He emigrated to Switzerland in 1939 and lived there in relative isolation until his death in 1942.

In addition to chlorophyll, Willstätter investigated anthocyanins (the red, purple, and blue pigments in flowers and fruits) and carotenoids, the pigments responsible for yellow and orange coloration in plants. His systematic study of these pigment classes helped establish natural product chemistry as applied to biological coloration.