Collision‐induced loss of AgH from Ag⁺ adducts of alkylamines, aminocarboxylic acids and alkyl benzyl ethers leads exclusively to thermodynamically favored product ions

Abstract

The loss of AgH from [M+Ag]+ precursor ions of tertiary amines, aminocarboxylic acids and aryl alkyl ethers is examined by deuterium labeling combined with collision activation (CA) dissociation experiments. It was possible to demonstrate that the AgH loss process is highly selective toward the hydride abstraction. For tertiary amines and aminocarboxylic acids, hydrogen originates from the alpha-methylene group carrying the nitrogen function (formation of an immonium ion). In all cases examined, the most stable, i.e. the thermodynamically favored product ion is formed. In the AgH loss process, a large isotope effect operates discriminating against the loss of D. The [M+Ag]+ ion of benzyl methyl ether loses a hydride ion exclusively from the benzylic methylene group supporting the experimental finding that the AgH loss reaction selectively cleaves the weakest C-H bond available.

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].…”

“…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]. However, in the collisional activations of argentinated chalcones, a distinct AgH loss has been discovered resulting from Oxo-Diels-Alder reaction rather than 1,2-elimination, while a peculiar AgOH loss is ascertained as the result of Nazarov cyclization [31].…”

Gold Ion–Angiotensin Peptide Interaction by Mass Spectrometry

“…With the development of gentle ionization techniques such as ESI [29,30] and MALDI [31,32] for transferring peptides/proteins into the gas phase without detrimental effects on their integrity, mass spectrometry has been used successfully to characterize metal cation (such as calcium, cadmium, cobalt, copper, iron, magnesium, mercury, nickel, potassium, sodium, and zinc) peptide/protein interactions [33][34][35][36][37][38][39][40][41][42][43][44][45][46]. Data reveals some general findings such as various metal ions may interact differently to a peptide sequence [33,47], and the metal cation-peptide/protein bond is believed to be noncovalent [33].…”

Gas‐Phase Synthesis and Intense Visible Absorption of Tryptophan–Gold Cations

“…How-ever, loss of AgH was recently observed with other amino acids. [15] The high coordination of gold with Trp also has an influence on the optical properties of the complex. Figure 3 a compares the experimentally recorded photodissociation Figure 3 b) is in full agreement with the experimental findings.…”