SSOH and HSSO Radicals:  An Experimental and Theoretical Study of [S₂OH]^0/+/- Species

Abstract

New radicals containing sulfur-sulfur bonds are detected in the gas phase: disulfur hydroxide SSOH and thiosulfenoxide HSSO, stable toward dissociation by ca. 50 and 40 kcal mol(-1), respectively. Energetic, structural features and fragmentation pathways of these [S2OH] radicals and their charged species [S2OH]+ and [S2OH]- are experimentally and computationally investigated by mass spectrometric techniques and ab initio calculations. [S2OH]+ is obtained by various ion-molecule reactions leading to S2O protonated on the oxygen and end-sulfur atoms, whose proton affinity is computed at different levels of theory. The first detection of [S2OH]-, the conjugate base of the oxatrisulfane HSSOH, is also reported.

Thermolysis of 3,3,5,5‐Tetramethyl‐1,2,4‐trithiolane 1‐Oxide: First Matrix Isolation of the HOSS· Radical

“…In accordance with earlier theoretical studies of the isomeric radicals 16 and 18 ,8 the CCSD(T)‐FC/cc‐pVTZ‐optimized geometry shows a planar ( C s ) cisoid structure for 16 as an energy minimum. Computation of the internal rotation energy profile identified the planar transoid conformation as a transition structure associated with a barrier of ca.…”

“…The corresponding UV/Vis spectrum revealed two strong absorption bands located at λ max = 290 and 385 nm (Figure 2). The first absorption displays a resolved vibrational structure that belongs to 14 , whereas the second band can be assigned to radical 16 , the existence of which in the gas phase was previously proven by neutralization‐reionization mass spectrometric measurements 8. The absorption band of 16 observed experimentally was in good agreement with the most intense computed electronic transitions at λ max = 377 nm ( f = 0.0294).…”

A Computational Study of the Reaction Cyanoacetylene and Cyano Radical Leading to 2-Butynedinitrile and Hydrogen Radical

“…The Potential Energy Surface (PES) of the system was investigated through the optimization of the most stable stationary points. Following a well established computational scheme [20][21][22][23][24][25][26], we optimized the geometry of the stationary points, both minima and saddle points, using a less expensive method with respect to the one employed in order to get accurate energies. Calculations for geometries were performed in order to benchmark three methods: density functional theory, with the Becke-3-parameter exchange and Lee-Yang-Parr correlation (B3LYP) [27,28], Unrestricted-Hartree-Fock (UHF) [29,30], and post Hartree-Fock B2PLYP [31] combined or not with Grimme's D3BJ dispersion [32,33].…”

Iron‐Promoted CC Bond Formation in the Gas Phase

“…[17] Thep otential energy surface of the species of interest was investigatedbylocating the lowest stationary points at the BPW91/6-311 + G** level of theory, [18] and the energy of the main stationary points was computed at the higher level of calculation CCSD(T)/6-311 + G**. [17] Thep otential energy surface of the species of interest was investigatedbylocating the lowest stationary points at the BPW91/6-311 + G** level of theory, [18] and the energy of the main stationary points was computed at the higher level of calculation CCSD(T)/6-311 + G**.…”

“…Theexperiments were performedusing amodified LTQXLlinear ion trap mass spectrometer( Thermo Fisher Scientific) fitted with an electrospray ionization (ESI) source,a nd am odified ZABSpec oa-TOFi nstrument( VG Micromass) of EBE-TOF configuration described elsewhere. [17] Thep otential energy surface of the species of interest was investigatedbylocating the lowest stationary points at the BPW91/6-311 + G** level of theory, [18] and the energy of the main stationary points was computed at the higher level of calculation CCSD(T)/6-311 + G**. [19] Experimentald etails and computational methods are described in the Supporting Information.…”