Structure of [Pb(Gly-H)]+ and the Monosolvated Water and Methanol Solvated Species by Infrared Multiple-Photon Dissociation Spectroscopy, Energy-Resolved Collision-Induced Dissociation, and Electronic Structure Calculations

Abstract

Infrared multiple-photon dissociation (IRMPD) spectroscopy, collision-induced dissociation mass spectrometry, and theoretical calculations are combined to provide new insights into the structure and dissociation of lead(II) complexed with the conjugate acid of the amino acid glycine ([Pb(Gly-H)](+)) in the presence and absence of solvent. Unexpectedly, these experiments show the main site of lead(II) coordination to be the deprotonated amino group of glycine, with additional coordination to the carbonyl group. In such a structure lead(II) can act as an effective conduit for proton/hydrogen shifts, making H(2)O loss competitive with that of CO in the [Pb(Gly-H)](+) complex and leading to solvent deprotonation and formation of [PbOR(Gly)](+) (R = H, CH(3)) ions when solvent is present in the complex. The structural assignments based on IRMPD spectroscopy are complemented with isotopic labeling experiments (H(2)(18)O) and experiments done on the ethyl ester of glycine.