{sup 1}H and {sup 15}N dynamic nuclear polarization studies of carbazole
{sup 15}N NMR experiments, combined with dynamic nuclear polarization (DNP), are reported on carbazole doped with the stable free radical 1,3-bisdiphenylene-2-phenylallyl (BDPA). Doping shortens the nuclear relaxation times and provides paramagnetic centers that can be used to enhance the nuclear si...
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Veröffentlicht in: | The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2000-05, Vol.104 (19) |
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Sprache: | eng |
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Zusammenfassung: | {sup 15}N NMR experiments, combined with dynamic nuclear polarization (DNP), are reported on carbazole doped with the stable free radical 1,3-bisdiphenylene-2-phenylallyl (BDPA). Doping shortens the nuclear relaxation times and provides paramagnetic centers that can be used to enhance the nuclear signal by means of DNP so that {sup 15}N NMR experiments can be done in minutes. The factors were measured in a 1.4 T external field, using both unlabeled and 98% {sup 15}N labeled carbazole with doping levels varying between 0.65 and 5.0 wt {degree} BDPA. A doping level of approximately 1 wt {degree} produced optimal results. DNP enhancement factors of 35 and 930 were obtained for {sup 1}H and {sup 15}N, respectively, making it possible to perform {sup 15}N DNP NMR experiments at the natural abundance level. |
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ISSN: | 1089-5639 1520-5215 |
DOI: | 10.1021/jp9938011 |