Gas-phase infrared multiple photon dissociation spectroscopy of mass-selected molecular ions

Oomens, Jos; Sartakov, Boris G.; Meijer, Gerard; Helden, Gert von

doi:10.1016/j.ijms.2006.05.009

Cited by 499 publications

(665 citation statements)

References 133 publications

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“…Note that the ion has to absorb multiple photons (i.e., tens to hundreds) to reach the dissociation threshold. The mechanism of infrared multiple-photon dissociation (IR-MPD) has been described in detail previously [31,32]. In a separate experiment, [Trp ϩ K] ϩ was deuterated using a constant background pressure of ND 3 (8 ϫ 10 Ϫ7 mbar) for 6 s. The singly deuterated ion (at m/z 244) was again mass isolated and probed by IR spectroscopy, as described above.…”

Section: Experimental and Calculationsmentioning

confidence: 99%

Observation of zwitterion formation in the gas-phase H/D-exchange with CH₃OD: Solution-phase structures in the gas phase

Polfer

Dunbar

2007

J. Am. Soc. Mass Spectrom.

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Infrared spectroscopy of gas-phase singly deuterated [Trp ϩ K] ϩ (formed by H/D exchange with CH 3 OD) shows that some (ϳ20%) kinetically stable zwitterionic (ZW) conformer is formed, based on the diagnostic antisymmetric CO stretch of the deprotonated carboxylate moiety, as (CO 2 Ϫ ), at 1680 cm Ϫ1 . A majority of the deuterated [Trp ϩ K] ϩ is found to be in the charge solvation (CS) conformation, with deuterium exchange occurring on both the acid and amino groups, which is consistent with H/D scrambling. Interestingly, H/D exchange with the more basic ND 3 reagent did not result in the stabilization of a kinetically stable zwitterion, although it is not clear yet what causes this observation. The result for CH 3 OD shows that H/D exchange can in fact alter the structure of the analyte and, hence, care needs to be taken when interpreting gas-phase H/D exchange studies. Moreover, this result shows the possibility of forming solution-phase structures that are thermodynamically disfavored in the gas phase, thus opening a new area of study. (HDX) is one of the most popular techniques for the structural elucidation of biomolecules in mass spectrometry and has been widely implemented for both solution [1][2][3][4] and gas phase studies [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In solution, the extent of HDX can be directly related to the solvent accessibility of amino acid residues in proteins. However, in the gas phase there are many structural parameters apart from the surface availability that affect the HDX rates, as illustrated in a recent HDX study on ion-mobilityselected charge states of bovine ubiquitin [17]. Systematic studies on small peptide systems showed that the difference in proton affinity of the biomolecules and deuterated donor reagent plays a crucial role in the HDX mechanism [7][8][9][10]19]. Beauchamp and coworkers [9] suggested that lower basicity reagents, such as D 2 O and CH 3 OD, proceed via a "relay" mechanism [20] for protonated peptides, while the higher basicity ND 3 reagent gives rise to an "onium" mechanism [21]. In the case of amino acids cationized by an alkali metal ion rather than a proton, polar deuterating ligands such as D 2 O can exchange via a similar relay mechanism involving charge solvation-zwitterion (CS-ZW) isomerization [18]. Modeling of observed HDX processes and quantum chemical calculations of the potential surfaces have made a strong circumstantial case that ZW structures are traversed in many cases during HDX with basic partners like D 2 O, CH 3 OD, and ND 3 [14,16,18]. Nevertheless, computations also generally indicate that the bare ZW is sufficiently disfavored energetically that its equilibrium presence in the M ϩ /amino acid would be negligible [22,23].Here, we show unambiguous spectroscopic evidence that bare ZW can in fact be kinetically trapped as a result of the HDX of [Trp ϩ K] ϩ with CH 3 OD. Infrared multiple-photon dissociation (IR-MPD) spectroscopy of metal-tagged amino acids and peptides has already been shown to be a powerful probe for CS ...

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Section: Experimental and Calculationsmentioning

confidence: 99%

Observation of zwitterion formation in the gas-phase H/D-exchange with CH₃OD: Solution-phase structures in the gas phase

Polfer

Dunbar

2007

J. Am. Soc. Mass Spectrom.

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“…T he combination of ion-trapping mass spectrometers and free-electron lasers tunable through the mid-infrared region of the electromagnetic spectrum have provided invaluable access to the vibrational spectra of discrete, gas-phase metal complexes [1][2][3][4][5][6][7][8][9][10]. It is generally difficult to acquire a conventional linear absorption spectrum of species commonly investigated by mass spectrometry because of the low ion concentrations.…”

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confidence: 99%

IRMPD spectroscopy of anionic group II metal nitrate cluster ions

Leavitt

Dain

Steill

et al. 2009

J. Am. Soc. Mass Spectrom.

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Anionic group II metal nitrate clusters of the formula [M 2 (NO 3 ) 5 ] -, where M 2 ϭ Mg 2 , MgCa, Ca 2 , and Sr 2 , are investigated by infrared multiple photon dissociation (IRMPD) spectroscopy to obtain vibrational spectra in the mid-IR region. The IR spectra are dominated by the symmetric and the antisymmetric nitrate stretches, with the latter split into high and low-frequency components due to the distortion of nitrate anion symmetry by interactions with the cation. Density functional theory (DFT) is used to predict geometries and vibrational spectra for comparison to the experimental spectra. Calculations yield two stable isomers: the first one contains two terminal nitrate anions on each cation and a single bridging nitrate ("mono-bridging"), while the second structure features a single terminal nitrate on each cation with three bridging nitrate ligands ("tri-bridging"). The tri-bridging isomer is calculated to be lower in energy than the mono-bridging one for all species. Theoretical spectra of the tri-bridging structure provide a better qualitative match to the experimental infrared spectra of T he combination of ion-trapping mass spectrometers and free-electron lasers tunable through the mid-infrared region of the electromagnetic spectrum have provided invaluable access to the vibrational spectra of discrete, gas-phase metal complexes [1][2][3][4][5][6][7][8][9][10]. It is generally difficult to acquire a conventional linear absorption spectrum of species commonly investigated by mass spectrometry because of the low ion concentrations. However, use of an action spectroscopy approach allows photon absorption to be monitored by measuring fragmentation yields that result from wavelength-specific infrared multiple-photon dissociation (IRMPD) [11][12][13].Using the uranyl (UO 2 2ϩ ) and the europium (Eu 3ϩ ) cations, our group produced the first vibrational spectra of gas-phase metal nitrate anions of the formula [UO 2 (NO 3 ) 3 ] -and [Eu(NO 3 ) 4 ] - [14]. These experiments were carried out at the FOM Institute for Plasma Physics in Nieuwegein, The Netherlands, using the free electron laser for infrared experiments (FELIX). FELIX provides a tunable, high-intensity beam of photons across the mid-IR range to a high-resolution mass spectrometer. The IRMPD spectra of both the uranyl and europium nitrate anions are dominated by the antisymmetric nitrate stretch ( 3 ), which is split into low and high-frequency components corresponding to the O-N-O (O-atoms involved in bonding with the metal), and (non-coordinating) NϭO stretches respectively. Previous studies have shown that the splitting of the 3 (⌬ 3 ) is proportional to the interaction strength between the metal and the nitrate ligands [15,16]. In the uranyl and europium nitrate anions, ⌬ 3 was found to be 264 cm -1 and 273 cm -1 respectively [14].In a later study, IRMPD spectroscopy was used to record vibrational spectra of anionic group II metal nitrate complexes of the formula [M(NO 3 ) 3 ] -where M ϭ Mg 2ϩ , Ca 2ϩ , Sr 2ϩ , and Ba 2ϩ [17]. By observ...

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“…It is a well-known feature of the IRMPD spectra of noncovalent adducts that contain NH and OH hydrogen-bond donors that their stretching vibrations can be more or less red-shifted and broadened, depending upon their relevant dissociation threshold. [34,46,47,[50][51][52][53][54][55][56] The broad resonances at 3100-3300 cm À1 …”

Section: Discussionmentioning

confidence: 99%

“…This probability does not only depend on the efficiency of the resonant photon absorption, but also on the efficiency of the IVR process, as well as on the dissociation energy barrier. [56] Thus, it is possible that the resonant absorption by a given IR-active vibrational mode in a complex does produce a signal with a relative intensity that is different from the corresponding calculated linear IR-absorption intensity.…”

Section: Full Papermentioning

confidence: 99%

Chirality Effects on the IRMPD Spectra of Basket Resorcinarene/Nucleoside Complexes

Filippi

Fraschetti

Piccirillo

et al. 2012

Chemistry A European J

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The IRMPD spectra of the ESI‐formed proton‐bound complexes of the R,R,R,R‐ and S,S,S,S‐enantiomers of a bis(diamido)‐bridged basket resorcin[4]arene (R and S) with cytosine (1), cytidine (2), and cytarabine (3) were measured in the region 2800–3600 cm−1. Comparison of the IRMPD spectra with the corresponding ONIOM (B3LYP/6‐31(d):UFF)‐calculated absorption frequencies allowed the assessment of the vibrational modes that are responsible for the observed spectroscopic features. All of the complexes investigated, apart from [R⋅H⋅3]+, showed similar IRMPD spectra, which points to similar structural and conformational landscapes. Their IRMPD spectra agree with the formation of several isomeric structures in the ESI source, wherein the N(3)‐protonated guest establishes noncovalent interactions with the host amidocarbonyl groups that are either oriented inside the host cavity or outside it between one of the bridged side‐chains and the upper aromatic nucleus. The IRMPD spectrum of the [R⋅H⋅3]+ complex was clearly different from the others. This difference is attributed to the effect of intramolecular hydrogen‐bonding interactions between the C(2′)OH group and the aglycone oxygen atom of the nucleosidic guest upon repulsive interactions between the same oxygen atom and the aromatic rings of the host.

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Gas-phase infrared multiple photon dissociation spectroscopy of mass-selected molecular ions

Cited by 499 publications

References 133 publications

Observation of zwitterion formation in the gas-phase H/D-exchange with CH₃OD: Solution-phase structures in the gas phase

Observation of zwitterion formation in the gas-phase H/D-exchange with CH₃OD: Solution-phase structures in the gas phase

IRMPD spectroscopy of anionic group II metal nitrate cluster ions

Chirality Effects on the IRMPD Spectra of Basket Resorcinarene/Nucleoside Complexes

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Gas-phase infrared multiple photon dissociation spectroscopy of mass-selected molecular ions

Cited by 499 publications

References 133 publications

Observation of zwitterion formation in the gas-phase H/D-exchange with CH3OD: Solution-phase structures in the gas phase

Observation of zwitterion formation in the gas-phase H/D-exchange with CH3OD: Solution-phase structures in the gas phase

IRMPD spectroscopy of anionic group II metal nitrate cluster ions

Chirality Effects on the IRMPD Spectra of Basket Resorcinarene/Nucleoside Complexes

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Observation of zwitterion formation in the gas-phase H/D-exchange with CH₃OD: Solution-phase structures in the gas phase

Observation of zwitterion formation in the gas-phase H/D-exchange with CH₃OD: Solution-phase structures in the gas phase