Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Harman, David G.; Blanksby, Stephen J.

doi:10.1039/b711156h

Cited by 64 publications

(97 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…102,103 Most recently, modifications made to commercial linear quadrupole ion trap mass spectrometers (LQIT) have facilitated the study of gas-phase ion-molecule reactions in these instruments. 104,105 The most important modification involved adding a mixing system to introduce neutral reagents into the trap via a syringe drive.…”

Section: Experimental Methodsmentioning

confidence: 99%

Properties and Reactivity of Gaseous Distonic Radical Ions with Aryl Radical Sites

et al. 2013

View full text Add to dashboard Cite

Section: Experimental Methodsmentioning

confidence: 99%

Properties and Reactivity of Gaseous Distonic Radical Ions with Aryl Radical Sites

et al. 2013

View full text Add to dashboard Cite

“…27 The TEMPO-Bz modified peptide ions are mass-selected, isolated, and thermalised (ca. 307 K) 48 in the helium buffer gas (2.5 mTorr helium). The ion ensemble is then irradiated with a single pulse from either a fixed-frequency (266 nm) or tunable (300 -220 nm) nanosecond laser system, the ion trap is scanned out and a PD mass spectrum is recorded containing signals for both photoproduct ions and the intact precursor ion population.…”

Section: Mass Spectrometrymentioning

confidence: 99%

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules

Marshall

Hansen

Trevitt

et al. 2014

Phys. Chem. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules AbstractRadical-directed dissociation of gas phase ions is emerging as a powerful and complementary alternative to traditional tandem mass spectrometric techniques for biomolecular structural analysis. Previous studies have identified that coupling of 2-[(2,2,6,6-tetramethylpiperidin-1-oxyl)methyl]benzoic acid (TEMPO-Bz) to the N-terminus of a peptide introduces a labile oxygen-carbon bond that can be selectively activated upon collisional activation to produce a radical ion. Here we demonstrate that structurally-defined peptide radical ions can also be generated upon UV laser photodissociation of the same TEMPO-Bz derivatives in a linear ion-trap mass spectrometer. When subjected to further mass spectrometric analyses, the radical ions formed by a single laser pulse undergo identical dissociations as those formed by collisional activation of the same precursor ion, and can thus be used to derive molecular structure. Mapping the initial radical formation process as a function of photon energy by photodissociation action spectroscopy reveals that photoproduct formation is selective but occurs only in modest yield across the wavelength range (300-220 nm), with the photoproduct yield maximised between 235 and 225 nm. Based on the analysis of a set of model compounds, structural modifications to the TEMPO-Bz derivative are suggested to optimise radical photoproduct yield. Future development of such probes offers the advantage of increased sensitivity and selectivity for radicaldirected dissociation. AbstractRadical-directed dissociation of gas phase ions is emerging as a powerful and complementary alternative to traditional tandem mass spectrometric techniques for biomolecular structural analysis. Previous studies have identified that coupling of 2-[(2,2,6,6-tetramethylpiperidin-1-oxyl)methyl]benzoic acid (TEMPO-Bz) to the N-terminus of a peptide introduces a labile oxygen-carbon bond that can be selectively activated upon collisional activation to produce a radical ion. Here we demonstrate that structurally-defined peptide radical ions can also be generated upon UV laser photodissociation of the same TEMPO-Bz derivatives in a linear ion-trap mass spectrometer. When subjected to further mass spectrometric analyses, the radical ions formed by a single laser pulse undergo identical dissociations as those formed by collisional activation of the same precursor ion, and can thus be used to derive molecular structure. Mapping the initial radical formation process as a function of photon energy by photodissociation action spectroscopy reveals that photoproduct formation is selective but occurs only in modest yield across the wavelength range (300 -220 nm), with the photoproduct yield maximised between 235 and 225 nm. Based on the analysis of a set of model compounds, structural modifications to the TEMPO-Bz derivative are suggested to optimise radical photoproduct yield. Future development of such probes offers t...

show abstract

“…The linear ion--trap mass spectrometer has previously been modified to perform both photodissociation [17,18] and ion--molecule reactions [19]. Typical source parameters were: spray voltage +3.0--4.5 kV; capillary temperature 200--250 °C; sheath gas flow between 10 and 30 (arbitrary units); and sweep and auxiliary gas flow set at between 0 and 10 (arbitrary units).…”

Section: Mass Spectrometrymentioning

confidence: 99%

“…Modifications to the linear ion--trap mass spectrometer that allow the introduction of neutral gases into the ion--trap region of the instrument have been described previously [19]. Briefly, reagent gases in a syringe are introduced into a flow of Ultra High Purity (UHP) helium (3--5 psi) via a heated septum inlet (25--250 °C).…”

Section: Ion--molecule Reactionsmentioning

confidence: 99%

“…The gas mixture is introduced into the ion trap via a variable leak valve, which is adjusted to set an ion trap pressure of 2.5 mTorr. The temperature of the vacuum manifold surrounding the ion trap was measured at 307 ± 1 K, which is taken as being the effective temperature for ion--molecule reactions observed therein [19,22] Reaction times of 30--10000 ms were set using the excitation time parameter within the control software using a normalized collision energy of 0 (arbitrary units).…”

Section: Ion--molecule Reactionsmentioning

confidence: 99%

See 1 more Smart Citation

Does Addition of NO₂ to Carbon-Centered Radicals Yield RONO or RNO₂? An Investigation Using Distonic Radical Ions

Kirk

Trevitt

Blanksby

2013

J. Am. Soc. Mass Spectrom.

Self Cite

View full text Add to dashboard Cite

Nitrogen dioxide is used as a "radical scavenger" to probe the position of carbon-centered radicals within complex radical ions in the gas phase. As with analogous neutral radical reactions, this addition results in formation of an [M + NO2](+) adduct, but the structural identity of this species remains ambiguous. Specifically, the question remains: do such adducts have a nitro-(RNO2) or nitrosoxy-(RONO) moiety, or are both isomers present in the adduct population? In order to elucidate the products of such reactions, we have prepared and isolated three distonic phenyl radical cations and observed their reactions with nitrogen dioxide in the gas phase by ion-trap mass spectrometry. In each case, stabilized [M + NO2](+) adduct ions are observed and isolated. The structure of these adducts is probed by collision-induced dissociation and ultraviolet photodissociation action spectroscopy and a comparison made to the analogous spectra of authentic nitro-and nitrosoxy-benzenes. We demonstrate unequivocally that for the phenyl radical cations studied here, all stabilized [M + NO2](+) adducts are exclusively nitrobenzenes. Electronic structure calculations support these mass spectrometric observations and suggest that, under low-pressure conditions, the nitrosoxy-isomer is unlikely to be isolated from the reaction of an alkyl or aryl radical with NO2. The combined experimental and theoretical results lead to the prediction that stabilization of the nitrosoxy-isomer will only be possible for systems wherein the energy required for dissociation of the RO-NO bond (or other low energy fragmentation channels) rises close to, or above, the energy of the separated reactants. AbstractNitrogen dioxide is used as a "radical scavenger" to probe the position of carbon--centered radicals within complex radical ions in the gas phase. As with analogous neutral radical reactions, this addition results in formation of an [M+NO2] + adduct, but the structural identity of this species remains ambiguous. Specifically, the question remains: do such adducts have a nitro--(RNO2) or nitrosoxy--(RONO) moiety, or are both isomers present in the adduct population? In order to elucidate the products of such reactions, we have prepared and isolated three distonic phenyl radical cations and observed their reactions with nitrogen dioxide in the gas phase by ion--trap mass spectrometry. In each case, stabilized [M + NO2] + adduct ions are observed and isolated. The structure of these adducts is probed by collision--induced dissociation and ultraviolet photodissociation action spectroscopy and a comparison made to the analogous spectra of authentic nitro--and nitrosoxy--benzenes. We demonstrate unequivocally that, for the phenyl radical cations studied here, all stabilized [M + NO2] + adducts are exclusively nitrobenzenes. Electronic structure calculations support these mass spectrometric observations and suggest that, under low--pressure conditions, the nitrosoxy--isomer is unlikely to be isolated from the reaction of an alkyl or aryl radical ...

show abstract

Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Cited by 64 publications

References 42 publications

Properties and Reactivity of Gaseous Distonic Radical Ions with Aryl Radical Sites

Properties and Reactivity of Gaseous Distonic Radical Ions with Aryl Radical Sites

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules

Does Addition of NO₂ to Carbon-Centered Radicals Yield RONO or RNO₂? An Investigation Using Distonic Radical Ions

Contact Info

Product

Resources

About

Investigation of the gas phase reactivity of the 1-adamantyl radical using a distonic radical anion approach

Cited by 64 publications

References 42 publications

Properties and Reactivity of Gaseous Distonic Radical Ions with Aryl Radical Sites

Properties and Reactivity of Gaseous Distonic Radical Ions with Aryl Radical Sites

Photodissociation of TEMPO-modified peptides: new approaches to radical-directed dissociation of biomolecules

Does Addition of NO2 to Carbon-Centered Radicals Yield RONO or RNO2? An Investigation Using Distonic Radical Ions

Contact Info

Product

Resources

About

Does Addition of NO₂ to Carbon-Centered Radicals Yield RONO or RNO₂? An Investigation Using Distonic Radical Ions