Characterization of the triplet state of aromatic esters and nitriles. Evaluation of the steric effect on the triplet of methyl mesitoate

1977 ◽  
Vol 55 (14) ◽  
pp. 2728-2731 ◽  
Author(s):  
D. R. Arnold ◽  
J. R. Bolton ◽  
G. E. Palmer ◽  
K. V. Prabhu
Keyword(s):  
Electron Spin Resonance ◽  
Steric Effect ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Triplet Energy ◽  
Field Splitting ◽  
Aromatic Esters ◽  
Spin Resonance ◽  
Phosphorescence Emission

The phosphorescence emission and electron spin resonance spectra of methyl mesitoate (1) and mesitonitrile (2) have been studied in order to assess the steric effect (inhibition of resonance) in the former. The triplet energy of 1 (80.5 kcal mol−1) is considerably higher than that of 2 (74.2 kcal mol−1) while the zero-field splitting parameters are very similar (1, D/hc = 0.127 cm−1, E/hc = 0.013 cm−1; 2, D/hc = 0.127 cm−1, E/hc = 0.006 cm−1). The triplet energy and zero-field splitting parameters of o-, m-, and p-methyl toluate and o-, m-, and p-tolunitrile are also reported.

ELECTRON SPIN RESONANCE OF Fe+3 IN CORDIERITE

1966 ◽  
Vol 44 (11) ◽  
pp. 2749-2755 ◽  
Author(s):  
N. E. Hedgecock ◽  
S. C. Chakravartty
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
Orthorhombic Symmetry ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Spin Resonance

ESR spectra of Fe+3 located at one of the aluminium sites in cordierite have been investigated at X- and K-band frequencies at room temperature. The spectra exhibit large zero-field splitting and have been fitted to a spin Hamiltonian of orthorhombic symmetry, having constants b20 = 14.6 ± 0.1 kG, b22 = 8.5 ± 0.1 kG, and isotropic g = 2.004 ± 0.002.

Electron Spin Resonance of Cr3+ in K1–xTlxAl(SO4)2 · 12 H2O

2003 ◽  
Vol 58 (5-6) ◽  
pp. 303-305 ◽  
Author(s):  
V. K. Jain
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Metal Ion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Trivalent Metal ◽  
Zero Field Splitting Parameter ◽  
Monovalent Ions ◽  
Spin Resonance ◽  
Splitting Parameter

The electron spin resonance (ESR) of Cr3+ in K1−xTlxAl(SO4)2·12H2O has been studied at 300 K and 9.45 GHz. The ESR spectrum for x between 30 and 90% shows several chromium complexes. The variation of the zero-field splitting parameter D suggests that monovalent ions play an important role in the trigonal distortion of the water octahedron around the trivalent metal ion in alums. - PASC: 76.30 F.

Conformational dependence of electronic spectra and zero-field splitting parameters in 2-naphthylphenylcarbene

1995 ◽  
Vol 73 (11) ◽  
pp. 1869-1874 ◽  
Author(s):  
Olivier Parisel ◽  
Gaston Berthier ◽  
Eva Migirdicyan
Keyword(s):  
Transition Energy ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Triplet Energy ◽  
Field Splitting ◽  
Clear Cut ◽  
Zero Field Splitting Parameter ◽  
Splitting Parameter ◽  
Semi Empirical ◽  
Ci Calculations

Quantum mechanical calculations using ab initio and semi-empirical methods have been carried out for elucidating the electronic structure and geometry of 2-naphthylphenylcarbene conformers. The Z/cis conformer has the lowest ground state triplet energy, the lowest triplet–triplet (T0–T1) transition energy, as well as the largest zero-field splitting parameter D. A clear-cut relationship between the D value and the geometry is pointed out. Keywords: carbenes, conformational isomerism, triplet–triplet transitions, CS-INDO/CI calculations, ZFS D parameters.

Effects of Additional Linkers in Biphenyl-4,4‘-dinitrene on the Low-Lying Singlet−Triplet Energy Gap and Zero-Field Splitting

1997 ◽  
Vol 101 (11) ◽  
pp. 2083-2088 ◽  
Author(s):  
Shigeaki Nimura ◽  
Osamu Kikuchi ◽  
Tsuguyori Ohana ◽  
Akira Yabe ◽  
Shigeo Kondo ◽  
...  
Keyword(s):  
Energy Gap ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Triplet Energy ◽  
Field Splitting

Electron spin resonance studies of 53Cr3+ and VO2+ ions in AlCl3∙6H2O

1976 ◽  
Vol 54 (2) ◽  
pp. 217-222 ◽  
Author(s):  
K. Pack ◽  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Double Resonance ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Electron Nuclear Double Resonance ◽  
Spin Resonance ◽  
Impurity Doping ◽  
Static Distortion

The electron-nuclear double resonance (ENDOR) of 53Cr3+ ions and the electron spin resonance (ESR) of VO2+ ions are studied in single crystals of AlCl3∙6H2O. The ENDOR measurements are done at 4.2 K while the resonance of VO2+ is studied at room temperature. The sign of the Cr3+ spin Hamiltonian zero field splitting parameter D is found to be negative while the anisotropic hyperfine parameter has the relation A < B. It is concluded that the octahedron of waters surrounding the chromium ion is trigonally compressed. The value of the 53Cr3+ quadrupole interaction parameter Q′ is nearly the same as that found previously in the cesium alums even though the D value is considerably smaller in AlCl3∙6H2O. This indicates that Q′ is independent of D at 4.2 K in these salts and the expected proportionality [Formula: see text], which is based on a purely static distortion for the octahedron of waters surrounding the Cr3+ ion, does not hold. The resonance results for VO2+ show the nature of the two inequivalent but otherwise similar Al∙6H2O complexes in the unit cell. The VO2+∙5H2O complexes associated with the two types of aluminum sites are found to be rotated relative to each other by an angle of 33 ± 3° in the plane perpendicular to the crystal c axis. A comparison of the spin Hamiltonian parameters of VO2+ and 53Cr3+ in AlCl3∙6H2O with those obtained previously in CsAl alum indicates that the Al∙6H2O complexes in CsAl alum are more susceptible to distortion upon impurity doping than are those in AlCl3∙6H2O.

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