ELECTRON SPIN RESONANCE STUDY OF PAIRING THEOREM FOR ALTERNANT HYDROCARBONS .2. 13C HYPERFINE SPLITTINGS IN POSITIVE AND NEGATIVE IONS OF BIPHENYLENE

被引:20
作者
HINDLE, PR
VEIGA, JDS
BOLTON, JR
机构
[1] Department of Chemistry, University of Minnesota, Minneapolis, MN
[2] Chemistry Department, University of Waterloo, Waterloo, Ont.
[3] Chemistry Department, University of Coimbra, Coimbra
关键词
D O I
10.1063/1.1668049
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The pairing theorem predicts that for alternant hydrocarbon radical ions, the spin densities at corresponding positions should be the same. Although proton hyperfine splittings do show significant differences, the 18C splittings appear to be more analogous, at least for the anthracene ions. The biphenylene ions are unusual in that one of the proton hyperfine splittings shows an anomalous variation. It is thus of interest to see whether this variation is due to a breakdown of the pairing theorem or to an anomalous variation in the sigma-pi parameter QCHH Two of the three 13C splittings were obtained in both the negative and positive ions of biphenylene. Signs and assignments were obtained on the basis of linewidth variations. The 13C splittings at corresponding positions were found to be almost identical. This result seems to imply that the anomalous variation in the proton hyperfine splittings is due to a change in QCH H and not to a redistribution of the spin densities.
引用
收藏
页码:4703 / +
页数:1
相关论文
共 37 条
[1]   SIGNS OF ISOTROPIC HYPERFINE SPLITTINGS IN ELECTRON SPIN RESONANCE SPECTRUM OF DIHYDROPYRAZINE CATION RADICAL [J].
BARTON, BL ;
FRAENDEL, GK .
JOURNAL OF CHEMICAL PHYSICS, 1964, 41 (03) :695-+
[2]   SIGN OF C13 COUPLING CONSTANTS IN AROMATIC FREE RADICALS [J].
BOER, ED ;
MACKOR, EL .
JOURNAL OF CHEMICAL PHYSICS, 1963, 38 (06) :1450-&
[5]   ELECTRON SPIN RESONANCE STUDY OF PARING THEOREM FOR ALTERNANT HYDROCARBONS - 13C SPLITTINGS IN ANTHRACENE POSITIVE + NEGATIVE IONS [J].
BOLTON, JR ;
FRAENKEL, GK .
JOURNAL OF CHEMICAL PHYSICS, 1964, 40 (11) :3307-+
[6]   ASSIGNMENT OF HYPERFINE SPLITTINGS IN ELECTRON SPIN RESONANCE SPECTRA BY LINEWIDTH ANALYSES [J].
BOLTON, JR ;
FRAENKEL, GK .
JOURNAL OF CHEMICAL PHYSICS, 1964, 41 (04) :944-+
[8]   THE ELECTRON SPIN RESONANCE SPECTRA OF RADICAL-IONS DERIVED FROM BIPHENYLENE AND BINAPHTHYLENE [J].
CARRINGTON, A ;
DOSSANTOSVEIGA, J .
MOLECULAR PHYSICS, 1962, 5 (03) :285-290
[9]  
CARRINGTON A, J CHEM SOC, V1959, P947
[10]   ELECTRON SPIN RESONANCE OF BENZENE POSITIVE-ION RADICAL [J].
CARTER, MK ;
VINCOW, G .
JOURNAL OF CHEMICAL PHYSICS, 1967, 47 (01) :292-&