Two Novel Species, (Methoxycarbonyl)sulfenyl Thiocyanate and (Methoxycarbonyl)sulfenyl Selenocyanate: Spectroscopic Characterization by Photoelectron Spectroscopy and Quantum Chemical Investigation

Abstract

Keywords: Ab initio calculations / Dichalcogens / Electronic structure / Photoelectron spectroscopy Two novel dichalcogens, (methoxycarbonyl)sulfenyl thiocyanate, CH 3 OC(O)SSCN, and (methoxycarbonyl)sulfenyl selenocyanate, CH 3 OC(O)SSeCN have been generated in a convenient way by gas-solid reactions between CH 3 OC(O)SCl and AgSCN or AgSeCN. Photoelectron spectroscopy and theoretical calculations have been performed to investigate their electronic and geometrical structures. Both compounds are theoretically predicted to prefer gauche structure as the most stable conformation. In CH 3 OC(O)SSCN, the S-S bond length and the dihedral angle around the S-S bond for the

Gas‐Phase Generation, Structure, Spectroscopy, and Quantum Chemical Calculations of Fluorocarbonylsulfur Thiocyanate, FC(O)SSCN

“…The correlation between selected dichalcogenides is shown in Figure 5. The ionization process from the lone pairs of two S atoms is 0.5 eV, which is close to those of the parent compounds, HSSH (0.27 eV),54 FSSF (0.41 eV),54 and CH 3 OC(O)SSCN (0.41 eV)10 (Figure 5). These energy differences are smaller than those of heteronuclear systems.…”

“…According to the results of experiments, the most stable conformer of the FC(O)SSCH 3 molecule adopts a gauche conformation, characterized by a dihedral angle δ CSSC = 83.5° 6. Similar phenomena were found in CH 3 OC(O)SSCN,10 CH 3 C(O)OSSOC(O)CH 3 ,17 and ClSSCN 18. So the starting geometry of the gauche conformer of FC(O)SSCN for quantum chemical calculations was based on the structure of the gauche conformer of FC(O)SSCH 3 as measured by gas electron diffraction (GED).…”

“…The energy barrier for the S–S rotation is 3.83, 5.00, and 4.62 kcal/mol at the B3LYP/6‐31G(d), MP2/6‐31G(d), and HF/6‐31G(d) levels, respectively. This behavior is due to the S–S lone‐pair repulsion and steric interactions between FC(O) and CN moieties, which is similar toFC(O)SSCH 3 and CH 3 OC(O)SSCN 6,10…”

“…Photoelectron spectroscopy with a He I resonance source (58.4 nm) is an efficient method for investigating the valence electronic structure of unstable species in combination with DFT calculations 10,18,17,46. The He I photoelectron spectrum of FC(O)SSCN is presented in Figure 3.…”

“…Recently, gas electron diffraction (GED) or microwave spectroscopy studies on the structures of FC(O)SSCF 3 , FC(O)SSCH 3 , and FC(O)SSC(O)CF 3 have been performed in the gas phase 5–7. Experimental and theoretical studies on substituted disulfides are of great importance because results from these studies can provide a sound basis for unravelling the complexity of sulfur–sulfur bonding interactions 2,10…”