Photophysical and photochemical processes of 9,10-dihydro-9-silaphenanthrene derivatives: photochemical formation and electronic structure of 9-silaphenanthrenes.
Photophysical and photochemical processes of 9-methyl- and 9-phenyl-9,10-dihydro-9-silaphenanthrene derivatives have been studied at room temperature and 77 K in comparison with the carbon analogue, 9,10-dihydrophenanthrene. These 9,10-dihydro-9-silaphenanthrene derivatives show smaller fluorescence quantum yield and remarkably larger Stokes shifts than those of the carbon analogue. In contrast, their phosphorescence quantum yields are two times larger than those of the carbon analogue, although the absolute value is not so large (approximately 0.1). Reaction products and intermediates produced by the 266 nm light photolysis have been studied, and it has been confirmed that 9-methyl- and 9-phenyl-9-silaphenanthrenes have been photochemically formed in methylcyclohexane at 77 K, in addition to the formation of radical cations of 9,10-dihydro-9-silaphenanthrene derivatives and the carbon-centered radical: 9-hydro-9-silaphenanthrenyl radical.
Hiratsuka
Hiroshi
H
Department of Chemistry, Gunma University, Kiryu Gunma 376-8515 Japan. hiratuka@chem.gunma-u.ac.jp
Horiuchi
Hiroaki
H
Furukawa
Yasunari
Y
Watanabe
Hikaru
H
Ishihara
Akiko
A
Okutsu
Tetsuo
T
Tobita
Seiji
S
Yoshinaga
Tetsutaro
T
Shinohara
Akihiro
A
Tokitoh
Norihiro
N
Oba
Makoto
M
Nishiyama
Kozaburo
K
D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D015394:Molecular Structure; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry* / Q000528:radiation effects; D010616:Phenanthrenes / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry; D010782:Photolysis; D014466:Ultraviolet Rays
D005609:Free Radicals; D017646:Organosilicon Compounds; D010616:Phenanthrenes