Novel product ions of 2‐aminoanilide and benzimidazole Ag(I) complexes using electrospray ionization with multi‐stage tandem mass spectrometry

Abstract

Multi-stage tandem mass spectrometry of [M - H](+) ions resulting from Ag(+) complexes of 2-aminoanilides and benzimidazoles in CIS-MS experiments produced unique product ion cascades that exhibited complementary structural information to that obtained from tandem mass spectrometry of [M + H](+) and [M - H](-) ions by electrospray ionization (ESI). These observations may be broadly applicable to other compounds that are observed to form Ag(+) complexes and eliminate AgH.

Even‐electron [M–H]+ ions generated by loss of AgH from argentinated peptides with N‐terminal imine groups

“…Experiments show (a) formation of novel even‐electron peptide cations by CID and (b) the extent to which sequence ions (conventional b , a and y ions) are generated from peptides with fixed charge site and thus lacking a conventional mobile proton. We note that [M–H] + ion formation as a result of elimination of AgH has been reported for CID of Ag(I) complexes with 2‐aminoanilide and benzimidazole, and argeninated N ‐allylbenzamides . For these systems, interesting fragmentation cascades were also observed.…”

Gas-Phase Intramolecular Cyclization of Argentinated N-Allylbenzamides

“…In the gas-phase chemistry of numerous argentinated organic ligands, product ions retaining the silver ion are generally observed [23][24][25][26][27] except when elimination of AgR (R = CH 3 , ph) [27,28] or AgH [24][25][26][27][28][29][30] takes place. In the case of argentinated amines, aminocarboxylic acids, ethers, or compounds possessing at least one α-hydrogen to the amino nitrogen or ether oxygen, the α-hydrogen tends to cleave with the silver in a 1,2-elimination [28][29][30].…”

Electrospray mass spectrometry and molecular modeling study of formation and stability of silver complexes with diazaperylene and bisisoquinoline

“…Notable exceptions are observed earlier in coordination complexes with Ag + , leading to the loss of AgH. Collision‐induced dissociation of argentinated ions [M + Ag] + from a homologous series of 2‐aminoanilide and benzimidazole compounds demonstrated abundant [M─H] + ions resulting from AgH elimination . Fragmentations of [L + Ag] + complexes, where L are aromatic amino acids: Phe, Tyr, Trp, or His, have been exhaustively studied through CID and through deuterium labeling.…”

“…[7][8][9][10][11][12][13] Nitrogen heterocycles are intensely studied chelating ligands, and a number of complexes with pyridyl-related ligands have been studied by ESI-MS/MS methods. [14][15][16][17][18] Collision activation experiments were used to characterize the stability of aza metal complexes with silver. 19,20 Recently, we described the synthesis of a wide range of diazaperylenes as large-surface ligands with increased π-delocalization and the corresponding flexible nonplanar bisisoquinolines.…”