Photoinduced Sulfur-Nitrogen Bond Rotation and Thermal Nitrogen Inversion in Heterocumulene OSNSO

摘要

An exotic ternary S, N, O heterocumulene OSNSO in syn-syn ( A ) and syn-anti ( B ) conformations has been generated in the gas phase through flash vacuum pyrolysis of CF_(3)S(O)NSO at 700 K. Upon visible light irradiation (570 ± 20 or 532 nm), both A and B , isolated in cryogenic matrices (N_(2), Ne, Ar, and Kr, anti-anti conformer ( C ). The reverse conformational transformation occurs either through S═N bond rotation ( C to A and B ) under visible light irradiation (400 ± 20 nm) at 2.8 K or through thermal nitrogen inversion ( C to A ) in the temperature range of 20–30 K, for which an exceptionally low activation barrier of 1.18 ± 0.07 kcal mol~(–1) has been experimentally determined.