3-Carboxy-PROXYL

The encapsulation of small guest molecules was achieved by constructing the dendrimer shell in the presence of the guest molecules followed by extensive dialysis to remove free guest molecules in solution [11]. A variety of probe molecules were applied, including Rose Bengal, 7,7,8,8,-tetracyano-quino-dimethane (TCNQ) and 3-carboxy-PROXYL. UV-Vis, fluorescence and EPR... 

By carrying out the encapsulation reaction in the presence of a varying concentration of 3-carboxy-PROXYL, the number of entrapped radicals could be varied from 0.3 to 6.0 molecules per dendritic box as determined by electron spin resonance (ESR) spectroscopy [36]. Tbe number of 3-carboxy-PROXYL radicals in the dendritic box does not increase above six (Figure 9), clearly demonstrating that... 

Figure 9 Number of 3-carboxy-PROXYL radicals trapped in the dendritic box, as determined by ESR spectroscopy, versus the molar ratio of radical and dendrimer in the initial solution prior to the encapsulation reaction...

Figure 10 = 2 ESR spectram of a solid sample of 3-carboxy-PROXYL DAB- e afr-...

Sano et al reported the development and use of another new nitroxyl probe, carboxy-proxyl acetoxymethyl ester (CxP-AM) for brain imaging. Its advantage over previous probe molecules is that it is able to cross the blood-brain barrier, but once inside the brain it is hydrolysed and retained there. In vivo L-band EPRI measurements on mice injected intravenously with a solution of CxP-AM showed that the compound did indeed localise in the brain, in contrast to analogous experiments using two other carboxy-proxyl derivatives, both of which exhibited much more diffuse distributions in the head. The authors point out that, because of its specificity and longevity in the brain, the CxP-AM agent should have potential for the determination of redox status of this organ in models of disease. 

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