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The discovery of the chemical evolution of singlet oxygen. Some current chemical, photochemical, and biological applications
Author(s) -
Khan Ahsan Ullah
Publication year - 1991
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560390305
Subject(s) - chemistry , singlet oxygen , singlet state , photochemistry , excited state , chemical physics , oxygen , computational chemistry , atomic physics , physics , organic chemistry
From the speculations of G. N. Lewis in 1916, [J. Am. Chem. Soc. 38 , 762 (1916)], the spectral predictions of R.S. Mulliken [Nature 122 , 505 (1928)], and the quantum mechanical treatment by E. Hückel [Z. Phys. 60 , 423 (1930)], the three lowest states of molecular oxygen ( 3 Σ g − , 1 Δ g , and 1 Σ g + ) remained spectroscopic elusives until Gerhard and Lisa Herzberg [G. Herzberg, Nature 133 , 759 (1934); L. Herzberg and G. Herzberg, Astrophys. J. 105 , 353 (1947); G. Herzberg and L. Herzberg, Astrophys. J. 108 , 167 (1948)], precisely defined them by observed infared transitions. The excited singlets remained of interest mainly to atmospheric spectroscopists and astrophysicists, and research on these species was scarce. The discovery in 1963 by A.U. Khan and M. Kasha [J. Chem. Phys. 39 , 2105 (1963)] of the simple chemical production of singlet molecular oxygens by the aqueous reaction of hydrogen peroxide and hypochlorite released an explosion of research on the neglected species. Fifteen research symposia and research treatises confirm the broad range of chemical activities of singlet oxygen. The extension to biological systems is now proceeding, with surprising evidence of involvement of natural processes, including the action of singlet oxygen in white blood cell phagocytosis.