Quantum chemical study on the equilibrium geometries of S3 and S−3, The electron affinity of S3 and the low lying electronic states of S−3

Abstract

The geometries and relative stabilities of the open, C2v symmetric and closed, D3h symmetric forms of thiozone and its anion, the adiabatic electron affinity of S3 and the energies of the three low-lying excited electronic states of the thiozone anion (Ã 2B2,B̃ 2A1,C̃ 2A2) at the optimized geometry of the X̃ 2B1 ground state are computed employing coupled-cluster [CCSD(T)], second-order multireference perturbation theory (CASPT2), and multireference CI (MRCI and IC-MRCI) methods using large atomic natural orbital basis sets. In addition, the saddle point for the open→closed isomerization on the neutral S3 potential energy surface is being studied. Surprisingly, the calculations do not show the expected underestimation of the experimentally determined electron affinity, in sharp contrast to test calculations on the sulfur atom, the disulfur molecule, and earlier results for ozone. Apart from this, thiozone and its anion behave in many respects qualitatively similar as ozone and O−3, while quantitatively various differences are observed.

The role of polysulfide dianions and radical anions in the chemical, physical and biological sciences, including sulfur-based batteries

“…Copyright 2013The MRCI+Q/ANO6532 calculation yielded S-S bond lengths of 200.2 pm and an SSS bond angle of 115.11. The computed electron affinity of S 3 of 2.10 eV is in perfect agreement with photoelectron spectroscopic results (2.09 eV) 107. Other methods gave similar geometrical values, for example the following bond lengths d (pm) and angles a obtained at the B3LYP/6-31+G(2df,p) level: [S 3 ] À 201.8/115.81 (gas), 201.7/114.41 (PCM8), 201.7/114.11 (PCM78); [S 3 ] 2À 213.3/114.41 (gas), 211.9/111.21 (PCM78), 211.8/ 110.51 (PCM78).…”

Encapsulation and convex‐face thiozonolysis of triatomic sulfur (S3) with carbon nanotubes

“…Table gives the calculated properties and energetics of S 3 obtained from various theoretical methods. Except for SCF/DZ + P and M06‐2X/cc‐type, all calculations employed in Table favor the C 2v form of S 3 to the D 3h form by 2.8 to 7.9 kcal/mol . Reaching 2 from 1 is a high‐barrier process (24.8 to 36.9 kcal/mol); as reported before, the cyclization is symmetry forbidden attributed to the gain of a σ bond in 2 and the loss of a π bond in 1 .…”

Synthesis, Characterization, Mechanism of Decomposition, and Antiproliferative Activity of a Class of PEGylated Benzopolysulfanes Structurally Similar to the Natural Product Varacin

“…24 The resulting open-chain polysulfide anion ( 20 ) has the potential for thiozone (S 3 ) elimination driven by the delocalization of the negative charge in the remaining carbon-sulfur fragment ( 21 ) 24,25 followed by thiozonation of norbornene. Ab initio calculations predict the open C 2v zwitterionic form 26 of thiozone S 3 to be energetically preferred to the cyclic D 3h form. 27,28 …”