Tautomer aspects in the excited-state dynamics in 2-thiocytosine: intersystem crossing in the absence of the thiocarbonyl group

Chem. Sci., 2025, Advance Article DOI: 10.1039/D5SC01442E, Edge Article Bijay Duwal, Isabel Eder, Leticia González, Sebastian Mai, Susanne Ullrich Tautomerism of nucleobases and their thio-analogues plays a critical role in controlling their excited-state relaxation dynamics. We show how tautomerism—i.e., the presence of a thiocarbonyl group—in 2-thiocytosine governs intersystem crossing.