TY - JOUR
T1 - Ring deformation and π-electron redistribution of methylbenzenes induced by metal coordination
AU - Lee, Jung Sup
AU - Lei, Yuxiu
AU - Kumari, Sudesh
AU - Yang, Dong Sheng
PY - 2010/9/2
Y1 - 2010/9/2
N2 - Scandium (Sc) complexes of p-xylene, mesitylene, and hexamethylbenzene were produced in a laser-vaporization molecular beam source and studied with pulsed-field-ionization zero-electron-kinetic-energy spectroscopy, and density functional theory. In addition, infraredultraviolet resonant two-photon ionization spectra were recorded for Sc(hexamethylbenzene) in the CH stretching region. Adiabatic ionization energies and several vibrational frequencies of these complexes were obtained from the spectroscopic measurements, and electronic transitions were determined by combining the spectra with the theoretical data. The ionization energies of the three complexes decrease with increasing number of the methyl groups, whereas the metalligand stretching frequencies of the p-xylene and mesitylene complexes are essentially the same and slightly smaller than that of the hexamethylbenzene species. Unlike benzene, the arene ring of the methylbenzene molecules is bent and the π-electrons are localized in a 1,4-diene fashion upon Sc coordination. The distortion of the aromatic ring is due to differential metal binding with the ring carbon atoms in the low-spin ground electronic state.
AB - Scandium (Sc) complexes of p-xylene, mesitylene, and hexamethylbenzene were produced in a laser-vaporization molecular beam source and studied with pulsed-field-ionization zero-electron-kinetic-energy spectroscopy, and density functional theory. In addition, infraredultraviolet resonant two-photon ionization spectra were recorded for Sc(hexamethylbenzene) in the CH stretching region. Adiabatic ionization energies and several vibrational frequencies of these complexes were obtained from the spectroscopic measurements, and electronic transitions were determined by combining the spectra with the theoretical data. The ionization energies of the three complexes decrease with increasing number of the methyl groups, whereas the metalligand stretching frequencies of the p-xylene and mesitylene complexes are essentially the same and slightly smaller than that of the hexamethylbenzene species. Unlike benzene, the arene ring of the methylbenzene molecules is bent and the π-electrons are localized in a 1,4-diene fashion upon Sc coordination. The distortion of the aromatic ring is due to differential metal binding with the ring carbon atoms in the low-spin ground electronic state.
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U2 - 10.1021/jp105672b
DO - 10.1021/jp105672b
M3 - Article
C2 - 20701306
AN - SCOPUS:77956144728
SN - 1089-5639
VL - 114
SP - 9136
EP - 9143
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 34
ER -