Synthesis and properties of novel porphyrin spin probes containing isoindoline nitroxides.
We report the synthesis of novel spin-labeled porphyrins containing isoindoline nitroxides (TMIO-APTPP and TMIO-APTSPP) and their manganese complexes (Mn-TMIO-APTPP and Mn-TMIO-APTSPP). These compounds represent potential new tools for electron paramagnetic resonance (EPR) as well as novel spin probes. Both TMIO-APTPP and TMIO-APTSPP have characteristic UV absorption peaks of free base porphyrin, while the characteristic absorption peaks of their manganese complexes Mn-TMIO-APTPP and Mn-TMIO-APTSPP shifted to shorter wavelengths. Electron paramagnetic resonance (EPR) spectroscopy indicated that these compounds all exhibit hyperfine splittings characteristic of EPR spectra of tetramethylisoindoline nitroxides, the typical nitroxide g values of approximately 2.006, and nitrogen isotropic hyperfine coupling constants (a(N) values) of about 14 G (293 K). The observed linewidths (La) for TMIO-APTSPP (0.73 G) and Mn-TMIO-APTSPP (0.65 G) in distilled water are significantly narrower than for TMIO-APTPP (1.475 G) and Mn-TMIO-APTPP (1.55 G) in chloroform.
Yan
Guo-Ping
GP
School of Material Science and Engineering, Wuhan Institute of Technology, Wuhan 430073, People's Republic of China.
Bischa
Daniel
D
Bottle
Steven E
SE
D004578:Electron Spin Resonance Spectroscopy; D007211:Indoles / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry; D015335:Molecular Probes / Q000138:chemical synthesis / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry*; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*
D007211:Indoles; D015335:Molecular Probes; D009589:Nitrogen Oxides; D011166:Porphyrins; D008345:Manganese; C057812:indoline