TY - JOUR
T1 - Change in spin state and enhancement of redox reactivity of photoexcited states of aromatic carbonyl compounds by complexation with metal ion salts acting as Lewis acids. Lewis acid-catalyzed photoaddition of benzyltrimethylsilane and tetramethyltin via photoinduced electron transfer
AU - Fukuzumi, S.
AU - Satoh, N.
AU - Okamoto, T.
AU - Yasui, K.
AU - Suenobu, T.
AU - Seko, Y.
AU - Fujitsuka, M.
AU - Ito, O.
PY - 2001
Y1 - 2001
N2 - The lowest excited state of aromatic carbonyl compounds (naphthaldehydes, acetonaphthones, and 10-methylacridone) is changed from the n,π* triplet to the π,π* singlet which becomes lower in energy than the n,π* triplet by the complexation with metal ions such as Mg(ClO4)2 and Sc(OTf)3 (OTf = triflate), which act as Lewis acids. Remarkable positive shifts of the one-electron reduction potentials of the singlet excited states of the Lewis acid-carbonyl complexes (e.g., 1.3 V for the 1-naphthaldehyde-Sc(OTf)3 complex) as compared to those of the triplet excited states of uncomplexed carbonyl compounds result in a significant increase in the redox reactivity of the Lewis acid complexes vs uncomplexed carbonyl compounds in the photoinduced electron-transfer reactions. Such enhancement of the redox reactivity of the Lewis acid complexes leads to the efficient C-C bond formation between benzyltrimethylsilane and aromatic carbonyl compounds via the Lewis-acid-promoted photoinduced electron transfer. The quantum yield determinations, the fluorescence quenching, and direct detection of the reaction intermediates by means of laser flash photolysis experiments indicate that the Lewis acid-catalyzed photoaddition reactions proceed via photoinduced electron transfer from benzyltrimethylsilane to the singlet excited states of Lewis acid-carbonyl complexes.
AB - The lowest excited state of aromatic carbonyl compounds (naphthaldehydes, acetonaphthones, and 10-methylacridone) is changed from the n,π* triplet to the π,π* singlet which becomes lower in energy than the n,π* triplet by the complexation with metal ions such as Mg(ClO4)2 and Sc(OTf)3 (OTf = triflate), which act as Lewis acids. Remarkable positive shifts of the one-electron reduction potentials of the singlet excited states of the Lewis acid-carbonyl complexes (e.g., 1.3 V for the 1-naphthaldehyde-Sc(OTf)3 complex) as compared to those of the triplet excited states of uncomplexed carbonyl compounds result in a significant increase in the redox reactivity of the Lewis acid complexes vs uncomplexed carbonyl compounds in the photoinduced electron-transfer reactions. Such enhancement of the redox reactivity of the Lewis acid complexes leads to the efficient C-C bond formation between benzyltrimethylsilane and aromatic carbonyl compounds via the Lewis-acid-promoted photoinduced electron transfer. The quantum yield determinations, the fluorescence quenching, and direct detection of the reaction intermediates by means of laser flash photolysis experiments indicate that the Lewis acid-catalyzed photoaddition reactions proceed via photoinduced electron transfer from benzyltrimethylsilane to the singlet excited states of Lewis acid-carbonyl complexes.
UR - http://www.scopus.com/inward/record.url?scp=0034802161&partnerID=8YFLogxK
U2 - 10.1021/ja010125j
DO - 10.1021/ja010125j
M3 - Article
C2 - 11493049
AN - SCOPUS:0034802161
SN - 0002-7863
VL - 123
SP - 7756
EP - 7766
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 32
ER -