Water-proton relaxivity of hyperbranched polymers carrying TEMPO radicals

Hiroyuki Hayashi, Satoru Karasawa, Akihiro Tanaka, Keisuke Odoi, Katsumi Chikama, Hideto Kuribayashi, Noboru Koga

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13 Citations (Scopus)


High water-soluble hyperbranched poly(styrene) (HPS) polymers carrying stable 2,2,6,6-tetramethylpiperidine-1 -oxyl (TEMPO) radicals, HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)2, were prepared in ca. 60% introducing yield. HPS-N-TEMPO and HPS-Im-TEMPO were determined to be nearly spherical shapes of the diameter of 2.4 ± 0.6 and 2.2 ± 0.6 nm, respectively, by transmission electron microscope (TEM) images. The values of water-proton relaxivity, r1, at 25 MHz, 0.59 T, and 25°C were 6.0, 5.2, and 14 mM-1 sec-1 for HPS-N-TEMPO, HPS-Im-TEMPO, and HPS-Im-(TEMPO)2, respectively. The spin-lattice relaxation time (T1)-weighted images in phantom were also observed.

Original languageEnglish
Pages (from-to)201-204
Number of pages4
JournalMagnetic Resonance in Chemistry
Issue number3
Publication statusPublished - Mar 1 2009

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)


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