2-thioxo-1,2-dihydrobenzo[d][1,3]thiazin-4-one: Synthesis, crystal structure and its photoinduced proton transfer reaction
2-Thioxo-1,2-dihydrobenzo[d][1,3]thiazin-4-one (TDBTO), a new thiazin-one derivative, was synthesized and investigated. The crystal structure of TDBTO (C8H5NOS2, M-r = 193.8) was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P (1) over bar with a = 6.946(3), b = 7.402(3), c = 8.954(4) angstrom, alpha = 66.931(7)degrees, beta = 89.866(7)degrees, gamma = 72.289(7)degrees, V = 399.8(3) angstrom(3), Z = 2, M-r = 195.25, D-c = 1.622 g/cm(3), mu = 0.606 mm(-1), F(000) = 200, R = 0.0361 and wR = 0.1032. There exist intermolecular hydrogen bond of N(1)-H(1A)center dot center dot center dot O(1) and weak C(6)-H(6A)center dot center dot center dot O(1) contact in the structure as well as face-to-face pi-pi stacking interactions between the benzene ring and the thiazin ring of an adjacent benzothiazin unit. The photoinduced proton transfer reaction, transforming the initial thione into thiol form, was found, and the latter form was characterized by UV absorption spectra, fluo-rescence spectra and infrared spectra.