Resonance Raman spectra and structure of phenylthiyl radical

Tripathi, G. N. R.; Sun, Qun; Armstrong, David A.; Chipman, Daniel M.; Schüler, Robert H.

doi:10.1021/j100192a031

Cited by 68 publications

(94 citation statements)

References 8 publications

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“…The ground state of PhS • is 2 B 2 (defining the phenyl ring as the xy plane), and a CIS run was performed without symmetry to get a handle on the makeup on the low-lying excited states. Similar results were obtained as found in the literature with a different basis set: 50 the first three excited states were composed almost entirely of 2 B 1 , 2 A 2 , and 2 B 2 configurations, respectively. The 2 A 2 and 2 B 2 states are very similar in energy at this level of calculation, 21 000 and 22 600 cm -1 above ground state.…”

supporting

confidence: 91%

Quenching of Singlet Oxygen by Oxygen- and Sulfur-Centered Radicals: Evidence for Energy Transfer to Peroxyl Radicals in Solution

et al. 1998

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Quenching of singlet oxygen luminescence at 1.27 µm by PhS • , PhSO • , and peroxyl radicals PhOO • , t-BuOO • , PhCH 2 OO • , Ph 2 CHOO • , and Ph 3 COO • was studied in liquid solution. The quantum yields of decomposition of different initiators which lead to the formation of free radicals were measured by using nanosecond transient absorption. This allowed determination of singlet oxygen O 2 ( 1 ∆ g ) quenching rate constants by the radicals. They are <2 × 10 8 M -1 s -1 for the sulfur-centered radicals and (2-7) × 10 9 M -1 s -1 for peroxyl radicals in acetonitrile. The rapid quenching is attributed to energy transfer quenching by the peroxyls, which have an n f π* transition leading to a low-lying 2 A′ state above their 2 A′′ ground state. PhSO • is shown computationally not to have such a low-lying 2 A′ state. There may be a very low-lying 2 B 1 state, for PhS • , but it is apparently not an efficient acceptor of electronic energy from O 2 ( 1 ∆ g ).

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supporting

confidence: 91%

Quenching of Singlet Oxygen by Oxygen- and Sulfur-Centered Radicals: Evidence for Energy Transfer to Peroxyl Radicals in Solution

et al. 1998

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“…a; the bands belong to v s (C–C), δ(C–C), δ(CH 3 ), ν(C–C–C), d (C–H), δ(C–H), d (C–H) and δ(C–H) appear at 1602, 1560, 1490, 1320, 1275, 1172,1026 and 662 cm −1 , respectively. In this case, the band at 1602 cm −1 is assigned to the C–C symmetric stretching vibration of C–C = O, although the band at 1602 cm −1 is always assigned to the aromatic ring stretching of C = C, and the typical aromatic ring vibrations of graphite structure was found by casting polyacrylonitrile solution on a HNO 3 ‐etched silver foil, but the trends of a‐PMMA chains turning to a fused ring structure is impossible . The band at 1560 cm −1 is assigned to the C–C stretching vibration of C–CH 3 .…”

Section: Resultsmentioning

confidence: 98%

SERS study on surface chain geometry of atactic poly (methyl methacrylate) film and nanosphere

Chen

Zhang

et al. 2013

J Raman Spectroscopy

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The surface chain geometry of atactic poly (methyl methacrylate) (a‐PMMA) film and nanosphere (NS) was revealed by surface‐enhanced Raman scattering (SERS) spectra. The Ag nanoparticles and nanoplates were prepared by electrochemical deposition and chemical synthesis for SERS substrates. The experimental results suggested that the molecular chain axis of a‐PMMA film adopted a trans‐conformation on bonding to Ag surface ascribed to the short‐range chemical (CHEM) effect according to the SERS selection rules. However, for the well‐coated monolayer of a‐PMMA NSs, the α‐CH3 in polymer chains stood vertically to the Ag surface due to the giant local electromagnetic effect, then the chain conformation presented in the interface between a‐PMMA NSs and Ag metal was adopted the opposite orientation compared with a‐PMMA film. The Raman enhancement of the Ag nanoparticles was more prominent than that of the Ag nanoplates due to the free energies of face‐centered cubic crystal faces in nanoparticles, but the single crystals with (111) plane of Ag nanoplates could improve the stability of SERS signals when the annealed temperature was above Tg of a‐PMMA NSs. The present work can provide some useful information of surface chain geometry and conformation of NSs for designing various materials with well‐defined structure via a‐PMMA NSs template. Copyright © 2013 John Wiley & Sons, Ltd.

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“…The structures of the phenoxyl and thiyl radicals have been calculated by theoretical methods. [14,15] The results show that the expected structural changes in comparison with their closed-shell phenolate and . www.chemeurj.org thiophenolate forms are only observed for the phenoxyl but not the thiyl radicals.…”

Section: Ma C H T U N G T R E N N U N G (L Bumentioning

confidence: 91%

Description of the Ground‐State Covalencies of the Bis(dithiolato) Transition‐Metal Complexes from X‐ray Absorption Spectroscopy and Time‐Dependent Density‐Functional Calculations

Ray

DeBeer

Solomon

et al. 2007

Chemistry A European J

217

227

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The electronic structures of [M(L(Bu))(2)](-) (L(Bu)=3,5-di-tert-butyl-1,2-benzenedithiol; M=Ni, Pd, Pt, Cu, Co, Au) complexes and their electrochemically generated oxidized and reduced forms have been investigated by using sulfur K-edge as well as metal K- and L-edge X-ray absorption spectroscopy. The electronic structure content of the sulfur K-edge spectra was determined through detailed comparison of experimental and theoretically calculated spectra. The calculations were based on a new simplified scheme based on quasi-relativistic time-dependent density functional theory (TD-DFT) and proved to be successful in the interpretation of the experimental data. It is shown that dithiolene ligands act as noninnocent ligands that are readily oxidized to the dithiosemiquinonate(-) forms. The extent of electron transfer strongly depends on the effective nuclear charge of the central metal, which in turn is influenced by its formal oxidation state, its position in the periodic table, and scalar relativistic effects for the heavier metals. Thus, the complexes [M(L(Bu))(2)](-) (M=Ni, Pd, Pt) and [Au(L(Bu))(2)] are best described as delocalized class III mixed-valence ligand radicals bound to low-spin d(8) central metal ions while [M(L(Bu))(2)](-) (M=Cu, Au) and [M(L(Bu))(2)](2-) (M=Ni, Pd, Pt) contain completely reduced dithiolato(2-) ligands. The case of [Co(L(Bu))(2)](-) remains ambiguous. On the methodological side, the calculation led to the new result that the transition dipole moment integral is noticeably different for S(1s)-->valence-pi versus S(1s)-->valence-sigma transitions, which is explained on the basis of the differences in radial distortion that accompany chemical bond formation. This is of importance in determining experimental covalencies for complexes with highly covalent metal-sulfur bonds from ligand K-edge absorption spectroscopy.

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Resonance Raman spectra and structure of phenylthiyl radical

Cited by 68 publications

References 8 publications

Quenching of Singlet Oxygen by Oxygen- and Sulfur-Centered Radicals: Evidence for Energy Transfer to Peroxyl Radicals in Solution

Quenching of Singlet Oxygen by Oxygen- and Sulfur-Centered Radicals: Evidence for Energy Transfer to Peroxyl Radicals in Solution

SERS study on surface chain geometry of atactic poly (methyl methacrylate) film and nanosphere

Description of the Ground‐State Covalencies of the Bis(dithiolato) Transition‐Metal Complexes from X‐ray Absorption Spectroscopy and Time‐Dependent Density‐Functional Calculations

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