Affiliation:
1. Université Paris-Saclay Univ Evry CY Cergy Paris Université CNRS LAMBE 91025 Evry-Courcouronnes France
2. Univ Rennes Ecole Nationale Supérieure de Chimie de Rennes CNRS ISCR – UMR6226 F-35000 Rennes France
3. Departamento de Química, Módulo 13 Facultad de Ciencias, and Institute of Advanced Chemical Sciences (IAdChem) Universidad Autónoma de Madrid Campus de Excelencia UAM-CSIC Cantoblanco, 28049 Madrid Spain
Abstract
AbstractThe gas‐phase reactivity towards cytosine (C) of alkylmercury cations CnH2n+1Hg+, and more particularly CH3Hg+, C2H5Hg+,n‐C4H9Hg+andt‐C4H9Hg+, has been studied for the first time by combining tandem mass spectrometry, infrared multiple photon dissociation spectroscopy (IRMPD) and density functional theory (DFT) calculations. Under electrospray conditions, the interaction ofCwith the cations derived from alkylmercury chloride compounds gives rise to a single type of complex of general formula [RHg(C)]+, except fort‐butylmercury which turned to be unreactive. Subsequent MS/MS experiments showed that [RHg]+ions (R=Me, Et, n‐Bu) exhibit a peculiar reactivity characterized by the transfer of the alkyl group, R, to the nucleobase leading to a [(C)R]+ion, accompanied by the reduction of the metal and loss of0Hg. As the length of the alkyl chain increases (n≥2), a new fragmentation path leading to protonated cytosine is opened, associated with the elimination of a Cn,H2n,Hg moiety. This latter process is clearly overwhelming withn‐BuHg+. The mechanisms associated with both dissociation channels were examined through the use of IRMPD data in the fingerprint region, and by exploring the corresponding potential energy surfaces in the DFT framework.
Funder
Ministerio de Universidades