Synthesis and photophysical properties of fluorescent 2-aryl-1,3-dialkylbenzimidazolium ions and a l-alkyl-2-arylbenzimidazole with excited state intramolecular proton-transfer

To improve the solubility, photostability and fluorescence quantum yield (Φ) of 2-arylbenzimidazolium ions the N-1 hydrogen was replaced by an alkyl group before N-3 was quatemized; this substitution did not reduce Φ, proving the absence of steric inhibition to attainment of coplanarity in the excited state. A related symmetrical 2,2′-arylenebis(1,3-dimethyldibenzimidazolium ion) had Φ = 0.86. The related 2,5-bis(1-methyl-2-benzimidazolyl)phenol had Φ = 0.38 at 22° as well as a very large Stokes' shift due to proton-transfer. These findings supported a new insight into the electron distribution of the first excited singlet state of oligophenylenes. The compounds are of interest as laser dyes and scintillation fluors.     

Lars Onsager (1903–1976), Chemist-Physicist, on the Silver Anniversary of His Death

The Norwegian-born theoretical chemist-physicist Lars Onsager (1903–1976) received the 1968 Nobel Prize for Chemistry for the discovery of the reciprocal relations bearing his name, which are fundamental for the thermodynamics of irreversible processes. A recipient of numerous awards and honorary degrees, which he did not receive until relatively late in life, he taught at the Johns Hopkins and Brown universities, but spent most of his academic career at Yale University (1933–1972). He spent his post-retirement years (1972–1976) as Distinguished University Professor at the University of Miamis Center for Theoretical Studies, where he continued his work with several postdoctoral research fellows.     

In Memoriam D. Stanley Tarbell (1913–1999), Chemist and Historian of Chemistry

Dr. Dean Stanley Tarbell, Distinguished Professor Emeritus of chemistry at Vanderbilt University, where he served on the faculty from 1967 to 1981, died on May 26, 1999 in Bolingbrook, Ill. Earlier he taught for many years and chaired the chemistry department at the University of Rochester. In retirement, he and his wife, Ann Tracy Tarbell, researched and wrote articles and books on the history of chemistry in the U.S. For his writings he received the American Chemical Societys Dexter Award for Distinguished Contributions to the History of Chemistry in 1989. He was an avid reader and book collector, a linguist who taught himself Arabic, Russian, and classical Greek, and a lifelong baseball fan.