Synthesis, characterization, and coordination chemistry of the 2-azaphenalenyl radical.
The 2-azaphenalenyl radical 2 has been synthesized and characterized by ESR spectroscopy. Variable-temperature ESR measurements were carried out on both the phenalenyl (1) and the 2-azaphenalenyl (2) radicals. The phenalenyl radical 1 has the known propensity to dimerize at temperatures below 20 degrees C, but unexpectedly less so than originally reported. The first experimental measurement of bond dissociation enthalpy for the dimerization of the phenalenyl radical 1 was obtained in CCl(4) (11.34 +/- 0.11 kcal/mol) and toluene (9.8 +/- 0.7 kcal/mol). The 2-azaphenalenyl radical 2 does not show a propensity to dimerize over the measurable temperature range (220-330 K), but does so in the presence of Cu(hfac)(2) (hfac = hexafluoroacetylacetonate). The latter complex was characterized by X-ray crystallography.
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
Shijun
S
Zheng
Jie
J
Lan
Saeed I
SI
Khan
Yves
Y
Rubin
D001372:Aza Compounds / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D007700:Kinetics; D008958:Models, Molecular; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D013816:Thermodynamics
D001372:Aza Compounds; D005609:Free Radicals; D011084:Polycyclic Aromatic Hydrocarbons