Gas-Phase Structure and Vibrational Spectra of Dimethoxydisulfane, (CH3O)2S2

Abstract

The gas-phase structure of dimethoxydisulfane (CHgCfhSa was determined by electron diffraction. The molecule is chainlike and of symmetry C\. Selected experimental geometrical parameters are d{SS) 196.0(3) pm, c?(SO) 165.3(3) pm, d(CO) 143.2(3) pm, a(OSS) 108.2(3)°, a(COS) 114.5(4)°, r(SS) 91(4)°, r(SO) ± 7(3)°. Abinitio MO calculations at the HF/6-311G** level resulted in three conformational isomers originating from rotation about the two SO bond axes. The most stable conformer among these is in keeping with the gasphase structure. The two other rotamers are both of symmetry C2. Infrared and Raman spectra of gaseous, liquid, and crystalline dimethoxydisulfane and its fully deuterated derivative were recorded. The 30 fundamental modes were assigned using the vibrational wavenumbers calculated for the three rotamers by the ab-initio MO method.

Disulfide Bond in Diethyl Disulfide: A Rotational Spectroscopic Study

“…The S–S bond length of ClSSCl is about 0.06 Å longer than that of FSSF whereas the valence angle α­(S–S–Cl) is comparable to the valence angle α­(S–S–F). These geometric parameters of ClSSCl are close to those of CH 3 OSSOCH 3 determined by electron diffraction …”

“…These geometric parameters of ClSSCl are close to those of CH 3 OSSOCH 3 determined by electron diffraction. 8 ■ CONCLUSIONS Rotational spectra of diethyl disulfide were measured and assigned by pulsed-jet FTMW spectroscopy. Two conformers were detected in the supersonic expansion.…”

“…Experimental − and theoretical − efforts have been devoted to investigate the conformational preferences and structures of dialkyl disulfides. Vibrational spectroscopy, , electron diffraction, and rotational spectroscopy ,, have been applied to investigate the structures and conformations of dimethyl disulfide.…”

Conformational Studies by Dynamic NMR. 63.1Stereodynamics of Dialkylamino Ethoxy Disulfides: S−S and S−N Rotation Processes

“…This model (sometimes referred to as negative hyperconjugation) 10,11a,b parallels the one proposed to account for the barrier of the S−N, N−C(O)X, and P−N rotation processes. Such an approach also explains the observation that in dialkoxy disulfides (ROSSOR) the S−S bond length is shorter , and the S−S rotational barrier higher , than in dialkyl disulfides (RSSR). Therefore, the more electronegative a substituent X in a XSSX derivative, the lower the energy of the X−S antibonding σ* orbital is expected to be, ,11b, thus making the π-type bond stronger, due to the more efficient n,σ* overlapping.…”

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

“…In recent years, it has been found that chalcogen–chalcogen interactions play a crucial role in the structure and reactivity of a great variety of chalcogen‐containing compounds 1,2. The chalcogen–chalcogen bonds in bivalent compounds (REE′R′, E, E′ = O, S, Se) are known to prefer gauche conformations, which is usually attributed to lone‐pair interactions 3. These interactions favor a dihedral angle of about 90°, and steric interactions between the substituents (R, R′) tend to increase this angle.…”