Abundant Dipositively Charged Protonated a2 and a3 Ions from Diproline and Triproline
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- 作者：Junfang Zhao ; Chi-Kit Siu ; Tujin Shi ; Alan C. Hopkinson ; K. W. Michael Siu*
- 刊名：Journal of Physical Chemistry B
- 出版年：2009
- 出版时间：April 9, 2009
- 年：2009
- 卷：113
- 期：14
- 页码：4963-4969
- 全文大小：350K
- 年卷期：v.113,no.14(April 9, 2009)
- ISSN：1520-5207
文摘
Abundant (a2 + H)2+ from diproline and (a3 + H)2+ from triproline were observed via collisionally activated charge disproportionation of [La(peptide)(CH3CN)1,2]3+. These small, dipositive ions with the charges formally located on the peptide backbone are stabilized by charge delocalization onto the pyrrolidine-derived rings, making their formation competitive against other monopositive ions. The (a2 + H)2+ and (a3 + H)2+ ions from diproline and triproline are major products in contrast with those derived from triglycine, whose unprecedented and surprising observations were recently reported (Shi et al. Angew. Chem., Int. Ed. 2008, 47, 8288−8291).