Electronic State of Anthra[1,9-bc : 4,10-b'c']dichromene and Structural Analysis of Its Endoperoxide

Tomohiro WATANABE, Tatsuya TACHIKAWA, Nobutaka KITAHARA, and Sumio TOKITA*

Department of Applied Chemistry, Faculty of Engineering, Saitama University
255 Shimo-Ohkubo, Urawa, 338 JAPAN

(Recieved : , 1996 ; Accepted for publication : , 1996)

Addition of singlet oxygen to aromatic compounds has attracted much attention for utilization in the photochromic systems. The regiospecificity accompanied with the addition of oxygen is altered by introduction of functional groups and it is difficult to determine where the addition occurs. We prepared single crystals of the endoperoxide of anthra[1,9-bc : 4,10-b'c'] dichromene (1) and determined the positions of singlet oxygen addition by X-ray crystallographic analysis. The positions are 9- and 10-positions of anthracene moieties but not the 1- and 4-positions, coincided with the prediction from the coefficients of highest occupied molecular orbital calculated by AM1 or PM3 procedure.

Key Words: Photochromism, X-ray crystallography, Anthradichromene, Endoperoxide, Molecular Orbital, Frontier Orbital, HOMO, MOPAC

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