Nonplanar structure of C6H5SCF3 facilitates πσ∗-mediated photodissociation reaction on the S1 state

Substitution-induced Nonplanarity of 3-Fluorothioanisole in the First Electronically Excited State

Vibronic spectra of 3-fluorothioanisole (3FTA) in the first electronic excited state (S₁) and the cationic ground state (D₀) have been obtained by one-color resonant two-photon ionization (1C-R2PI) and mass-analyzed threshold ionization (MATI) spectroscopy. Spectroscopic measurements and theoretical calculations indicate that both cis- and trans-rotamers of the 3FTA molecule are stable and coexist in the S₀ (the electronic ground state) and D₀ states, and the cis-rotamer is shown to be slightly more stable than the trans-rotamer. In the S₁ state, theoretical calculations predict a stable gauche-structure of 3FTA, manifested by the observation of strong activation of the vibrational modes involving the motion of the -SCH₃ group in the low-frequency regions of the 1C-R2PI and MATI spectra. The electronic excitation energy from the S₀ state to the S₁ state (E₁) and the adiabatic ionization energy (IE) are respectively determined to be 34 820 ± 3 and 65 468 ± 5 cm^-1 for cis-3FTA, and those of the trans-rotamer are respectively determined to be 35 047 ± 3 and 65 644 ± 5 cm^-1. The structural properties of the stable rotamers of 3FTA and their comparison with other F- and Cl-substituted thioanisole derivatives are discussed as well.

Synthesis of aryl α,α-difluoroethyl thioethers a novel structure motif in organic chemistry, and extending to aryl α,α-difluoro oxyethers

A method for the preparation of aryl α,α-difluoroethyl thioethers (ArSCF₂CH₃) is reported and the synthesis approach is extended to aryl α,α-difluoroethyl oxygen ethers.