EPR Spectra of a Mono- and a Hetero-Diradical in Nematic and Isotropic Phases
摘要:
A hybrid hydrazine-nitroxide monoradical and the corresponding heterohydrazyl-nitroxide diradical were used as probes in 4-cyano-4'-pentylbiphenyl liquid crystal. EPR data (hyperfine constants, rotational time, and anisotropy parameter values) are reported in the range of 25 degrees C-55 degrees C. It was shown by EPR spectrometry that the nitroxide moiety gives an anisotropic triplet line, while the hydrazyl moiety cannot be detected under these conditions.
EPR Spectra of a Mono- and a Hetero-Diradical in Nematic and Isotropic Phases
作者:G. Ionita、I. Zarafu、A. Paun、P. Ionita
DOI:10.1080/15421406.2012.676834
日期:2012.8.22
A hybrid hydrazine-nitroxide monoradical and the corresponding heterohydrazyl-nitroxide diradical were used as probes in 4-cyano-4'-pentylbiphenyl liquid crystal. EPR data (hyperfine constants, rotational time, and anisotropy parameter values) are reported in the range of 25 degrees C-55 degrees C. It was shown by EPR spectrometry that the nitroxide moiety gives an anisotropic triplet line, while the hydrazyl moiety cannot be detected under these conditions.
Synthesis and characterisation of some novel hetero-diradicals containing linked hydrazyl and aminoxyl (nitroxide) moieties
作者:Petre Ionita、Adrian C. Whitwood、Bruce C. Gilbert
DOI:10.1039/b102748b
日期:——
We report the synthesis and characterisation of some novel hydrazine-derived monoradicals incorporating nitroxide 14, nitronyl-nitroxide15 and imino-nitroxide 16 functions, as well as the corresponding diradicals assigned the hydrazyl-nitroxide 17, hydrazyl-nitronyl-nitroxide 18 and hydrazyl-imino-nitroxide 19 structures. EPR, UV-Vis and electrochemical (CV) characteristics are reported, along with MS and NMR data where appropriate; pKa and BDE values are calculated as well as the average interelectronic separation in the triplet diradicals 18 and 19 obtained via solid-state
EPR measurement and calculations. The reactions of these compounds with short-lived radicals generated by photolysis, as well with NO and NO2, are also reported.