TGE FT-ICR


Partenaires

CNRS
Logo Ecole Polytechnique Logo ESPCI
Logo UPS Logo UDL
Logo UPMC Logo Universite de Lille 1
Logo Rouen Logo INSA Rouen Normandie



Accueil du site > Production scientifique > Infrared spectrum of the Ag(+)-(pyridine)2 ionic complex : probing interactions in artificial metal-mediated base pairing

Infrared spectrum of the Ag(+)-(pyridine)2 ionic complex : probing interactions in artificial metal-mediated base pairing

Date de publication: 25 mars 2011

S. Chakraborty, O. Dopfer
Chemphyschem.  12(10) 1999-2008 (2011). DOI

Travail réalisé sur le site de l’Université Paris-Sud.

Abstract

The isolated pyridine-Ag(+)-pyridine unit (Py-Ag(+)-Py) is employed as a model system to characterize the recently observed Ag(+)-mediated base pairing in DNA oligonucleotides at the molecular level. The structure and infrared (IR) spectrum of the Ag(+)-Py(2) cationic complex are investigated in the gas phase by IR multiple-photon dissociation (IRMPD) spectroscopy and quantum chemical calculations to determine the preferred metal-ion binding site and other salient properties of the potential-energy surface. The IRMPD spectrum has been obtained in the 840-1720 cm(-1) fingerprint region by coupling the IR free electron laser at the Centre Laser Infrarouge d’Orsay (CLIO) with a Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer equipped with an electrospray ionization source. The spectroscopic results are interpreted with quantum chemical calculations conducted at the B3LYP/aug-cc-pVDZ level. The analysis of the IRMPD spectrum is consistent with a σ complex, in which the Ag(+) ion binds to the nitrogen lone pairs of the two Py ligands in a linear configuration. The binding motif of Py-Ag(+)-Py in the gas phase is the same as that observed in Ag(+)-mediated base pairing in solution. Ag(+) bonding to the π-electron system of the aromatic ring is predicted to be a substantially less-favorable binding motif.