Mechanisms of Photochemical Reactions in Solution. XXXIII. Intersystem Crossing Efficiencies

Abstract

A simple method for measurement of quantum yields for the singlet→triplet crossing process in solution has been developed. The compound to be tested is used as a sensitizer for one or more cis—trans isomerization reactions and the quantum yield of the induced process is measured. The results are discussed briefly

Photochemical synthesis 29. Photoannelation and cyclohexenone

“…Since it was found that sensitizers above 73 kcal/mole could induce photoannelation, but that nonetheless cyclopentenone quenched benzophenone triplets at a near diffusion controlled rate, it was suggested that T, was the reactive state and that T I (presumably below 68 kcal/mole) was inert in the photoannelation process. That the lowest triplet of cyclopentenone was below 68 kcal/mole was in accord with Leermaker's finding, from photoequilibration experiments, of a value of 62 kcall mole (3,19).…”

Synthesis of 2′,4‐Diarylbenzophenones through Site‐Selective Suzuki–Miyaura Reactions of Bis(triflates) of 2′,4‐Dihydroxybenzophenones

“…This method has been applied to the analysis of a variety of natural waters and sediments. [9] Several substituted benzophenones display phosphorescence. [10][11][12] Classic syntheses of benzophenones are based on reactions of aryllithium or magnesium reagents with aldehydes and subsequent oxidation and on Friedel-Crafts acylations.…”

Photochemistry of CS2/Cl complexes—combined pulse radiolysis–laser flash photolysis studies

“…The optical absorption of the naphthalene triplets formed by energy transfer from the benzophenone triplets was measured [ε 425 nm =1.32 x 10 4 dm 3 mol -1 cm -1 (Bensasson and Land, 1971), Φ = 1.0 (Lamola and Hammond, 1965)]. The maximum laser output per pulse was 10 mJ.…”