Crystal Structure of 1,3-Diphenyl-2,3-dihydro-1H-benzo[d][1,3]dithiole-1,3-dinium Bis(tetrafluoroborate) Acetonitrile Solvate

Abstract

Carbones (CL2) named by Frenking et al. have two electron lone pairs with σ and π symmetry at the divalent carbon(0) atom, which distinguishes them from carbenes, which have only one σ lone pair orbital.1 Therefore, they have been increasingly investigated in a field of extensive theoretical and experimental studies.2 The first member of this family was hexaphenylcarbodiphoshorane [C(PPh3)], reported in 1961.3 Recently, we extended the carbone chemistry toward the sulfur-stabilized carbones and revealed their carbone character by using the diauratedand proton-aurated complexes.4 However, there have been no reports of cyclic type compounds among the carbones with an S–C–S skeleton, and have also not been experimentally demonstrated their four-electron-donating ability, such as in dicationic salts. In this paper, we describes the X-ray structure of diprotonated 5-menbered cyclic carbone, 1,3-diphenyl-2,3dihydro-1H-benzo[d][1,3]dithiole-1,3-dinium. The title compound 1 (Fig. 1) was synthesized in 28% yield by the reaction of 1,2-bis(phenylthio)benzene with diiodomethane in the presence of AgBF4 in acetonitrile at reflux conditions. The spectral data of 1 are as follows: mp 122 – 125°C (decomp.), 1H NMR (CD3CN) δ 6.01 (s, 2H), 7.76 – 7.83 (m, 8H), 7.93 – 7.96 (m, 2H), 8.20 – 8.23 (m, 2H), 8.24 – 8.28 (m, 2H).13 C NMR (CD3CN) δ 60.3, 123.4, 130.1, 132.9, 133.07, 133.11, 137.95, 138.7. 19F NMR (CD3CN)δ –151.3. Single crystals of 1 were grown in acetonitrile/diethyl ether at room temperature. Data collection and refinement parameters are listed in Table 1. The H atoms were positioned with the idealized geometry, and were refined to be isotropic (Uiso(H) = 1.2Ueq(C)) using a riding model with C–H = 0.95 Å for aromatic H atoms, C–H = 0.99 Å for methylene H atoms and C–H = 2021 © The Japan Society for Analytical Chemistry