Stable gas-phase radical cations of dimeric tryptophan and tyrosine derivatives.

摘要: Stable radical cations of dimeric amino acid derivatives tryptophan and tyrosine were generated by collisioninduced dissociation [Cu II (diethylenetriamine)(amino derivative) 2] ¥2+ . The yields the dimer dependent on both auxiliary ligand or used. Amino with an unmodified carboxylic group did not generate cations. For Ac-Trp-OMe Ac-Trp-NH2 (Ac is N-acetyl; OMe NH2 are methyl ester amide modifications C-terminal group), no was required for generating Collision-induced (amino derivative)4] precursor cation [(amino ¥+ Stabilizing interactions, most likely involving hydrogen bonding, between two proposed to account observation Dissociation these ions protonated cationic derivatives; observations consistent expectation proton competition monomeric units, whose affinities calculated using density functional theory.