Synthesis and characterization of amino derivatives of persistent trityl radicals as dual function pH and oxygen paramagnetic probes.

摘要: Triarylmethyl radicals, TAMs, are useful soluble paramagnetic probes for EPR spectroscopic and imaging applications because of their extraordinary stability in living tissues, narrow line width, high analytical resolution at micromolar concentrations enhanced sensitivity to molecular oxygen. Recently we proposed the concept dual function pH oxygen TAM based on incorporation ionizable groups into structure (J. Am. Chem. Soc. 2007, 129 (23), 7240-7241). In this paper report synthesis derivatives containing amino groups. The synthesized TAMs combine with sensitivity, range from 6.8 9.0. To decrease number spectral components improve probe solubility physiological pH, asymmetric both carboxyl functions were synthesized. presence nitrogen hydrogen atoms direct proximity protonatable resulted strong pH-induced changes corresponding hyperfine splittings, Delta hfs approximately (300-1000) mG, comparable values themselves. Large pH-dependent shifts individual components, linewidths (160-280) allow easy discrimination between effect observed oxygen-dependent broadening about (6 +/- 0.5) mG per % represent first reasonably valuable properties biomedical research.