Pedersen, Charles John (1904-1989) was an American chemist who shared the 1987 Nobel Prize in chemistry with Donald James Cram of the United States and Jean-Marie Lehn of France. Pedersen received the prize for developing a group of organic compounds called macrocyclic polyethers, or crown ethers. Cram and Lehn expanded on Pedersen's research to produce artificial molecules.

Pedersen was born on Oct. 3, 1904, in Pusan, Korea, the son of Brede Pedersen, a Norwegian mechanical engineer, and Takino (Yasui) Pedersen, a woman from a Japanese merchant family. Pedersen attended preparatory school in Japan, and then went to the University of Dayton in Ohio, where he received a bachelor's degree in chemical engineering in 1926. He earned a master's degree in organic chemistry from Massachusetts Institute of Technology (MIT) in 1927.

That year, he joined E. I. du Pont de Nemours & Company of Wilmington, Delaware, as a research chemist. He remained at DuPont for his 42-year career, writing 25 technical papers and obtaining 65 patents, mainly in petrochemicals.

Pedersen's early work led to improvements in the process for making tetraethyl lead, a gasoline additive. He later worked on synthetic antioxidants. These compounds work to block the effects of oxidation, a chemical reaction in which a substance loses electrons, often while combining with oxygen.

Pedersen discovered crown ethers in the 1960's, reporting his findings in 1967, shortly before retirement. The molecules in crown ethers typically consist of carbon, hydrogen, and oxygen atoms arranged in a “crown” shape, or ring. By changing the structure of the crown, Pedersen could trap a variety of metal ions (electrically charged atoms or groups of atoms) in the center of the crown.

Cram and Lehn expanded on Pedersen's research to produce artificial molecules that can “recognize” one another and “choose” which other molecules they will combine with. These molecules can perform the same functions as molecules of living things, such as enzymes (molecules that speed up chemical reactions).