ï ï=ï-ï° Donald James( The American chemist, Nobel Prize in Chemistry, 1987)
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Biography ï ï=ï-ï° Donald James
Kram, Donald James (Cram, Donald J.), (1919-2001), American chemist, Nobel Prize in Chemistry, 1987 (jointly with Jean-m.Lenom and C. Pedersen).
Born April 22, 1919 in the small town of Chester, Vermont (USA). His father, a Scotsman by birth, first cavalry officer, then a lawyer, and then an unsuccessful farmer, and mother, a German by birth, moved here with her three children from Canada. Two years later the family moved to Brattlboro (Vermont). His father died when Donald was 4 years old.
Due to lack of funds from 14 years to earn money to pay for an apartment, laboring at the neighbors: raked leaves, hoeing corn, digging potatoes harvested hay and carried the newspaper.
At age 16, began an independent life. Moved to Florida, worked in a shop selling ice cream and weeding lawns at the table and the bed, still in school, but returned to hitchhike north to Massachusetts, where he spent the summer coloring at home, and repairing the roof. The last class graduated from the school in Winwood, a small private school on Long Island in New York, to pay tuition and meals, served in various assignments. At the same time he studied chemistry and solid geometry and the result has a four-year scholarships to the National Rollins College, located in the resort town of Winter Park, Florida.
Professor of Chemistry College, said Kram, that he did not have enough brains to become a scientist. Cram also studied the chemistry and philosophy. At the same time worked, to secure a tolerable existence. In the summer months from 1938 to 1941 he worked in New York in the National Biscuit Company, first as a traveling salesman, and then engaged in an analysis of cheese.
At this time he was awakened interest in research activities in the field of chemistry. This interest led him to the University of Nebraska, where in 1942 he received a Master's degree. During the Second World War, worked in the company 'Merck', where he focused on the problems of penicillin. In 1945 was hired by Harvard University, to Professor LF Fizeru. Dissertation work done in 18 months.
At Harvard, the scientific level for him embodied the well-known expert in the field of physical organic chemistry Paul Bartlett and R. B. Woodward (Nobel Laureate, 1965). But here he did not stay long. In 1947 began working in the University of California at Los Angeles, where he remained until the end of life
. In 1960 American Charles Pedersen synthesized compounds called crown ether (crown - in English crown) for the singularity of its structure - a blank inside and a movable ring of carbon atoms linked through a bridge oxygen atoms
. By varying the size of the cycle, he found that crown ethers are able to selectively bind certain cations, placing them in the center of its 'crown'.
Its discovery has been extended Frenchman Jean-Marie Lehn and Kramov. Result of parallel efforts of three researchers was the synthesis of molecules that can selectively react with other molecules, just like enzymes are associated with other natural molecules
. Cram distributed synthesis with two-dimensional organic compounds, . namely crown ethers, . to three-dimensional derivatives, . creating a number of different-sized molecules, . that can selectively interact with other substances because of the complementarity of their three-dimensional structures,
. His work was a significant step forward towards the establishment of substances in the laboratory, simulating the action of enzymes and other natural molecules whose specific behavior is determined by their characteristic structure.
Crown ethers were considered first as a model system, capable of selective binding. It turned out that they can serve as models of biological and transport systems. Next, determine the role of such compounds in modeling enzymes. Crown ethers were the first synthetic analogs of natural substances, implementing the transfer of alkali metal ions across the cell membrane. These vectors, called ionophore, operate on the same principle as crown ethers, although they have a more complicated structure. Natural vectors of cations belong to the so-called switchable ionophore. After going inside the cell, they are under the influence of certain influences thrown cation and quickly returned for the following. Speed of shuttle operations may reach several thousand per second, and often they occur against the concentration gradient.
Crown, as a substance that selectively bind certain ions, are promising for medicine as a treatment for metallodefitsitnyh and metalloizbytochnyh states.
This area of research has expanded rapidly evolved into what Len later named by the term 'supramolecular chemistry'. Supramolecular chemistry is studying aspects of the interactions of the molecules 'guest' molecule with a 'master'. Len has identified it as the chemistry of intermolecular bonds that studies the association of two or more chemical species, as well as the structure of such associations. It lies outside the classical chemistry that studies the structure, properties and transformations of individual molecules. If the latter is the case, . mainly, . with reactions, . in which there are gaps and the formation of valence bonds, . is an object of study of supramolecular chemistry are almost exclusively non-valent interactions: hydrogen bond, . electrostatic interactions, . hydrophobic forces, . structure 'no connection',
. As is known, the energy of non-valent interactions of 1-2 orders of magnitude below the energy of valence bonds, however, if many of them, they lead to the formation of strong, yet flexible to change its structure associates. This combination of strength and capacity for rapid and reversible changes - a characteristic property of all biological molecular structures: nucleic acids, proteins, enzymes, vectors of particles.
Within a short period of supramolecular chemistry has developed into a vast field of knowledge, which includes several areas. The most important direction of research the last decade was the synthesis of compounds that can form complexes of type 'guest-host' with organic molecules. It is necessary for the separation and purification of organic substances, their activation, to create next-generation drugs and the myriad of other scientific and applied problems.
In 1987, Cram was awarded the Nobel Prize (together with Jean-M.Lenom and C. Pedersen) 'for the development and application of molecules with structure-specific interactions of high selectivity'
. Cram taught Organic Chemistry at about 12 000 students and has written 3 textbooks: "Organic Chemistry" (with Dzh.Hemmondom (GSHammond), . published in 12 languages), . "Elements of Organic Chemistry" [with D. Richards (D. Richards) and Dzh.Hemmondom (GSHammond), . published in 3 languages] and the "Essence of Organic Chemistry" (with Dzh.Kram, . J. Cram), . and the monograph "Principles of Chemistry of carbanions",
His passion - surfing, skiing, tennis, playing guitar and folk songs.
He died of cancer June 17, 2001.