Infrared consequence spectroscopy of gaseous protonated and metal ion cationized complexes

Abstract

In this article, the new and exciting techniques of infrared consequence spectroscopy (sometimes called action spectroscopy) of gaseous ions are reviewed. These techniques include vibrational predissociation spectroscopy and infrared multiple photon dissociation spectroscopy and they typically complement one another in the systems studied and the information gained. In recent years infrared consequence spectroscopy has provided long-awaited direct evidence into the structures of gaseous ions from organometallic species to strong ionic hydrogen bonded structures to large biomolecules. Much is being learned with respect to the structures of ions without their stabilizing solvent which can be used to better understand the effect of solvent on their structures. This review mainly covers the topics with which the author has been directly involved in research: structures of proton-bound dimers, protonated amino acids and DNA bases, amino acid and DNA bases bound to metal ions and, more recently, solvated ionic complexes. It is hoped that this review reveals the impact that infrared consequence spectroscopy has had on the field of gaseous ion chemistry.

The hydrated Li+–adenine–thymine complex by IRMPD spectroscopy in the N–H/O–H stretching region

“…Over the past number of years, IRMPD spectroscopy has proven to be a valuable tool for obtaining structural insight into protonated and metal ion complexes of small biological molecules including amino acids, nucleobases, and peptides [71][72][73]. In this study, the technique is used in combination with computational methods to determine the structure of a lithium-A:T base pair complex as solvated by one water molecule.…”

Insights into the fragmentation pathways of gas-phase protonated sulfoserine

“…One of the most powerful techniques for this purpose is infrared multiple photon dissociation (IRMPD) spectroscopy [16,17]. Since infrared photodissociation is only induced when the impinging photon is of a resonant energy with a vibrational mode of the analyte, by recording photofragmentation as a function of photon energy, an IRMPD spectrum, analogous to a more traditional absorption IR spectrum, can be constructed.…”

Diagnostic NH and OH Vibrations for Oxazolone and Diketopiperazine Structures: b2 from Protonated Triglycine

“…I nfrared multiple photon dissociation (IRMPD) spectroscopy [1][2][3] is one of the most useful tools in elucidating the chemistry of peptide dissociation in the gas phase by virtue of chemically diagnostic vibrations that can be identified [4]. One of the "textbook" examples of this approach involves verifying the oxazolone structure of "b" fragment ions [5,6] formed from collision-induced dissociation (CID) of protonated peptides.…”

“…For the smallest b 2 fragments, such cyclic structures are known as diketopiperazine structures [16]. The majority of IRMPD spectroscopy studies on b 2 fragments have so far identified oxazolone structures [9,10,13,14]; however, for instance for histidine-containing b 2 , a mixture of oxazolone and diketopiperazine structures was confirmed [12]. All IRMPD spectroscopy studies described above have been carried out at the free electron laser (FEL) facilities FELIX in The Netherlands or CLIO in France [17,18].…”