Conformations of the S and S homocyclic radical cations

Ciosłowski, Jerzy; Szarecka, Agnieszka; Moncrieff, David

doi:10.1002/qua.10330

Cited by 3 publications

(1 citation statement)

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“…10 The structures of the monocations S 6 + and S 7 + have recently been calculated with the B3PW91 method. The cation S 6 + (D 3d symmetry) adopts a chair conformation 11,12 that is much more flat (torsion angle τ ) 62.4°) than in the neutral molecule (τ ) 73°). The seven-membered ring of the S 7 + cation is approximately of C 2 symmetry 11 rather than C s , as observed 7 and calculated 13 for S 7 .…”

Section: Introductionmentioning

confidence: 99%

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules S_n (n = 2−8)

2004

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The structures and thermodynamic properties of 32 cations of composition [HS n ] + with n ) 2-8 have been studied by ab initio methods at the G3X(MP2) level of theory. In the global minimum structures, the proton binds to a single sulfur atom and, except for n ) 2, this also holds for the less stable isomers. The binding energies at 0 K range from 619.4 kJ mol -1 in [HS 2 ] + to 835.6 kJ mol -1 in [S 5 -SH] + , which represents the global minimum structure of composition [HS 6 ] + . The protonated branched rings are also the global minimum structures in the case of S 7 and S 8 , whereas [HS 5 ] + is most stable with a five-membered homocycle. The smaller cations [HS n ] + (n ) 2-4) are all chainlike with the hydrogen atom at a chain end. Unexpectedly, singlet chainlike structures of [HS n ] + (n ) 2-8) with the hydrogen terminating the chain at one end are more stable than the corresponding triplet chains. The protonation of neutral sulfur molecules always takes place at the atom of highest negative charge and the charge transfer to the proton is between 0.77 and 0.86 electrons. The S-H bond lengths are calculated as in the range 135-139 pm. The effect of protonation on the sulfursulfur bonds is dramatic, as can be seen in the strong bond length alternation within the cyclic or chainlike structures with the weakest SS bonds originating from the three-coordinate atoms. Hence, there is a pronounced bond activation by protonation. The calculated gas-phase basicities of S 6 and S 8 are in good accord with the experimental values.

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Section: Introductionmentioning

confidence: 99%

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules S_n (n = 2−8)

2004

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Electrophilic Attack on Sulfur–Sulfur Bonds: Coordination of Lithium Cations to Sulfur‐Rich Molecules Studied by Ab Initio MO Methods

Steudel

Wong

Steudel

2005

Chemistry A European J

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Complex formation between gaseous Li+ ions and sulfur-containing neutral ligands, such as H2S, Me2Sn (n = 1-5; Me = CH3) and various isomers of hexasulfur (S6), has been studied by ab initio MO calculations at the G3X(MP2) level of theory. Generally, the formation of LiS(n) heterocycles and clusters is preferred in these reactions. The binding energies of the cation in the 29 complexes investigated range from -88 kJ mol(-1) for [H2SLi]+ to -189 kJ mol(-1) for the most stable isomer of [Me2S5Li]+ which contains three-coordinate Li+. Of the various S6 ligands (chair, boat, prism, branched ring, and triplet chain structures), two isomeric complexes containing the S5==S ligand have the highest binding energies (-163+/-1 kJ mol(-1)). However, the global minimum structure of [LiS6]+ is of C(3v) symmetry with the six-membered S(6) homocycle in the well-known chair conformation and three Li--S bonds with a length of 256 pm (binding energy: -134 kJ mol(-1)). Relatively unstable isomers of S6 are stabilized by complex formation with Li+. The interaction between the cation and the S6 ligands is mainly attributed to ion-dipole attraction with a little charge transfer, except in cations containing the six sulfur atoms in the form of separated neutral S2, S3, or S4 units, as in [Li(S3)2]+ and [Li(S2)(S4)]+. In the two most stable isomers of the [LiS6]+ complexes, the number of S--S bonds is at maximum and the coordination number of Li+ is either 3 or 4. A topological analysis of all investigated complexes revealed that the Li--S bonds of lengths below 280 pm are characterized by a maximum electron-density path and closed-shell interaction.

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Helium Droplets Doped with Sulfur and C₆₀

et al. 2015

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Clusters of sulfur are grown by passing superfluid helium nanodroplets through a pickup cell filled with sulfur vapor. In some experiments the droplets are codoped with C60. The doped droplets are collided with energetic electrons and the abundance distributions of positively and negatively charged cluster ions are recorded. We report, specifically, distributions of Sm+, Sm–, and C60Sm– containing up to 41 sulfur atoms. We also observe complexes of sulfur cluster anions with helium; distributions are presented for HenSm– with n ≤ 31 and m ≤ 3. The similarity between anionic and cationic C60Sm± spectra is in striking contrast to the large differences between spectra of Sm+ and Sm–.

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Conformations of the S and S homocyclic radical cations

Cited by 3 publications

References 13 publications

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules S_n (n = 2−8)

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules S_n (n = 2−8)

Electrophilic Attack on Sulfur–Sulfur Bonds: Coordination of Lithium Cations to Sulfur‐Rich Molecules Studied by Ab Initio MO Methods

Helium Droplets Doped with Sulfur and C₆₀

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Conformations of the S and S homocyclic radical cations

Cited by 3 publications

References 13 publications

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules Sn (n = 2−8)

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules Sn (n = 2−8)

Electrophilic Attack on Sulfur–Sulfur Bonds: Coordination of Lithium Cations to Sulfur‐Rich Molecules Studied by Ab Initio MO Methods

Helium Droplets Doped with Sulfur and C60

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Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules S_n (n = 2−8)

Electrophilic Attack on Sulfur−Sulfur Bonds. 1. Protonation of Various Isomers of the Homoatomic Sulfur Molecules S_n (n = 2−8)

Helium Droplets Doped with Sulfur and C₆₀