화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.113, No.14, 4963-4969, 2009
Abundant Dipositively Charged Protonated a(2) and a(3) Ions from Diproline and Triproline
Abundant (a(2) + H)(2+) from diproline and (a(3) + 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 (a(2) + H)(2+) and (a(3) + 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).