The Effect of ω-Substituted Acceptors in 4-Dimethylamino-trans-Styrenes on the Polarity in the Ground and Excited Singlet State
ABSTRACT The electric dipole moment in the ground (μg) and in the first excited singlet state (μe) of co-substituted acceptors in 4-dimethylamino-trans-styrenes (Z = P(S)Ph2 , P(O)Ph2 , SO2CH3 ) were determined by solvatochromic and thermochromic methods. The obtained values of μe and μg and the values for Z = CN and Z = NO 2 known from the literature [2] fulfill the linear relation between the dipole moments (μe or μg and the Hammett constants σp of the substituents. On pincreasing the electron-acceptor power of Z, μe grows faster than μg
Viscosity independence of the ratio of fluorescence lifetimes and quantum yields of ω-substituted 4- dimethylamino-trans-styrenes
Abstract The fluorescence lifetimes τ and quantum yields φ F of 4-dimethylamino-ω-diphenylphosphinyl- trans -styrene ( 2a ) and 4-dimethylamino-ω-methylsulphonyl- trans -styrene ( 3a ) were measured in n -paraffins ( n = 6 to n = 16) at 293 K. The ratio τ/φ F was found to be viscosity independent and equal to the radiative lifetime τ 0 ′ calculated from the integrated absorption spectrum. The strong fluorescence quenching and the shortening of the lifetime τ when reducing the viscosity are due to twisting around the double bond, resulting in trans-cis isomerization.
History of Amateurism in Men's Intercollegiate Athletics: The Continuance of a 19th-Century Anachronism in America
Claiming that American intercollegiate athletics are amateur at the end of the 20th century is an anachronism, for colleges in the 19th century took on professional characteristics. The upper-class British concept of amateurism did not work effectively in a more egalitarian and achievement-oriented American society. Hypocrisy resulted when colleges claimed amateurism while accepting such professional practices as hiring professional coaches, allowing athletes to play summer baseball for money, and paying athletes through grants-in-aid. Attempts to preserve amateurism, such as the Graham Plan in the 1930s and the Sanity Code in the 1940s and 1950s, yielded to the professional spirit. Thus, while Americans had generally rejected the upper-class British social hierarchy that fostered amateurism, they retained the name amateur, continuing the hypocrisy that had begun in the previous century.