Spin–orbit coupling in sulphur-containing purine derivatives. A comparison of caffeine and 6-thiocaffeine

Spin-orbit coupling in sulphur-containin

Spin-orbit coupling in sulphur-containing purine and pyrimidine derivatives. A comparison of caffeine and 6-thiocaffeine

✍ G. Lancelot; C. Helene 📂 Article 📅 1971 🏛 Elsevier Science 🌐 English ⚖ 581 KB

## Replacing an oxygen atom of caffeine by a sulphur atom leads to a red-shift of the absorption spectrum. a quenching of fluorescence, an incrcnse in the phosphorescence quantum yield and a drastic shortening of the phosphorcecence lifetime. Polarization studies sh;w that phosphorescence transiti