Isomerism of [64Cu-NOTA-Bn]-Labeled Radiotracers: Separation of Two Complex Isomers and Determination of Their Interconversion Energy Barrier Using Ion Pair Chromatography

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• 作者：Joern Schlesinger ; Johan Rajander ; Janne A. Ihalainen ; Dinesh Ramesh ; Patrik Eklund ; Veronica Fagerholm ; Pirjo Nuutila ; Olof Solin
• 刊名：Inorganic Chemistry
• 出版年：2011
• 出版时间：May 16, 2011
• 年：2011
• 卷：50
• 期：10
• 页码：4260-4271
• 全文大小：1061K
• 年卷期：v.50,no.10(May 16, 2011)
• ISSN：1520-510X

文摘

The model complex [p>64p>Cu((S)-p-NH₂-Bn-NOTA)]p>鈭?/sup> ([p>64p>Cu]1) was used to study the isomerism of [p>64p>Cu-NOTA-Bn]-labeled radiotracers. Two complex isomers [p>64p>Cu]1a and [p>64p>Cu]1b, which were formed at a ratio of 1:9 during the complexation of [p>64p>Cu]Cup>2+p> with (S)-p-NH₂-Bn-NOTA, were separated using ion pair chromatography. To study the interconversion, the nonradioactive complex isomers Cu1a and Cu1b were separated and thermally treated at 90 掳C in both ammonium acetate solution and deionized water. A faster interconversion rate was observed for both isomers with lower concentrations of ammonium ions. At the end of reaction, the thermodynamic Cu1a to Cu1b equilibrium ratio was 6:94. The particular energy barriers of the interconversion for Cu1a and Cu1b were 130 kJ molp>鈭?p> and 140 kJ molp>鈭?p>. Spectrophotometric measurements with Cu1a and Cu1b revealed two isomers adopting different geometrical configurations.