Charles J. Pedersen (1904-1989) was a research chemist with E.I. du Pont de Nemours & Company who spent most of his career at the Jackson Laboratory in Deepwater, New Jersey, and the Elastomer Chemicals Department in Wilmington, Delaware.

Pedersen was born in Pusan, Korea, on October 3, 1904. Pedersen’s Norwegian father, Brede Pedersen (1865-1932), was a mining engineer with the Oriental Consolidated Mining Company, an American firm that operated the Unsan gold mines in northern Korea. His mother, Takino Yashui (1874-1950), was the daughter of a Japanese merchant dealing in soybeans and silkworms.

Pedersen was educated at a Catholic preparatory school in Yokohama, Japan, run by the Marianist Order. In 1922, he came to the United States to attend the University of Dayton, also a Marianist institution. After receiving his bachelor’s degree in chemical engineering from Dayton in 1926, Pedersen was awarded a master’s degree in organic chemistry the following year from the Massachusetts Institute of Technology. Recognizing Pedersen’s promise, Professor James F. Norris (1871-1940) urged him to pursue a doctorate, but Pedersen opted to enter private industry instead.

Pedersen was hired by the DuPont Company in 1927. After spending thirty years with the Organic Chemicals Department at the Jackson Laboratory in Deepwater, New Jersey, Pedersen joined the newly formed Elastomer Chemicals Department in 1957. Early in his career, Pedersen’s investigations led to the development of a dramatically improved process for manufacturing tetraethyl lead, an important gasoline additive. His discoveries relating to the degradative effects of heavy metals on petroleum products resulted in thirty patents for antioxidants and other related products.

In 1946, Pedersen’s promotion to Research Associate, the company’s highest ranking research position, allowed him to design his own projects. In 1957, the Elastomer Chemicals Department was created from the Elastomers Division of the Organic Chemicals Department and Pedersen accepted an invitation to join the new staff at the Experimental Station in Wilmington, Delaware.

Although he was certainly one of DuPont’s most productive industrial chemists during his years at the Jackson Laboratory, Pedersen’s greatest achievement came during the final decade of his illustrious career. While conducting research on the catalytic action of trace heavy metals and methods of controlling them by means of organic ligands, Pedersen inadvertently discovered some unknown crystals. He found that by combining any methanol-soluble salt with sodium, he could dissolve this crystal in methanol. The crystal, which Pedersen named a crown ether, had a ring-shaped molecular structure containing hydrogen, carbon, and oxygen atoms. Each oxygen atom was bound between two carbon atoms and contained six oxygen atoms exposed along the inner wall of the ring. When the atoms of certain metallic elements such as sodium or potassium pass through the center of the ring, they attach themselves to the exposed oxygen atoms and fit together the way a key fits into a lock. These “crown compounds” then act as hosts, escorting their guest atoms to places they would otherwise be unable to travel. By accepting specific atoms for transport in this fashion, crown compounds mimic the catalytic functions performed by enzymes.

Pedersen’s contributions to modern chemistry were truly exceptional. In the twenty years following publication of his seminal paper, “Cyclic Polyethers and Their Complexes in Metal Salts,” J. Am. Chem. Soc. 89, 7017 (1967), this work was cited more than 1,500 times by other researchers. It is interesting to note that fewer than .005 percent of all papers garner as many as 300 citations.

In the course of his career, Pedersen was awarded a total of fifty-five United States patents and published fifteen papers. For his discovery of crown compounds, Pedersen shared the Nobel Prize in Chemistry for 1987 with Professors Donald J. Cram (1919-2001) of the University of California at Los Angeles and Jean-Marie Lehn (1939-) of the Institute de chemie at the Université Louis Pasteur in Strasbourg, France. He is still the only career DuPont scientist to have won chemistry’s most coveted prize. Pedersen died on October 27, 1989.