Spectroscopy and chemical dynamics of group II metal ion-formaldehyde complexes

Kleiber, P. D.; Lu, Wenyun; Abate, Yohannes

doi:10.1016/j.ijms.2007.09.002

Cited by 12 publications

(6 citation statements)

References 52 publications

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“…Scans of the dye laser frequency result in the continuous, featureless production of the three dissociative fragments. Contrast this to the work of Kleiber, − where the photodissociation spectroscopy of Mg + , Ca + , and Zn + −formaldehyde and −acetaldehyde complexes yielded fairly rich vibronic structure. In these studies, the cold cluster ion was generated in a laser-driven, supersonic expansion similar to that used here.…”

Section: Methodscontrasting

confidence: 91%

“…Such barrierless predissociation events are fast. Estimates of predissociation time scales are provided by the photodissociation action spectra of the similar cluster ion, Mg + −(OCH 2 ). − In this study, detection of the dissociated Mg + ion resulted in vibrational resonances with homogeneous line widths consistent with an upper state lifetime ∼500 fs. Such time scales suggest that the photolysis of the electrostatic bonds here occur significantly faster than the microseconds required for reactive dissociation.…”

Section: Resultsmentioning

confidence: 75%

“…Typical of mass spectrometric techniques, knowledge of the possible isomers present in a mass spectrum must be inferred through secondary techniques or determined by some other means. Here, previous experiments, − DFT theory, and this instrument’s secondary mass analysis are used to access the structure of the most likely Ni + (But) isomer responsible for the dissociative kinetics quantified in Table and presented in Figure .…”

Section: Resultsmentioning

confidence: 99%

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Reaction Rate Constants and Mechanistic Detail of the Ni⁺+ Butanone Reaction

et al. 2011

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The unimolecular decomposition kinetics of the jet-cooled Ni(+)-butanone cluster ion has been monitored over a range of internal energies (16000-18800 cm⁻¹). First-order rate constants are acquired for the precursor ion dissociation into three product channels. The temporal growth of each fragment ion is selectively monitored in a custom instrument and yields similar valued rate constants at a common ion internal energy. The decomposition reaction is proposed to proceed along two parallel reaction coordinates. Each dissociative pathway is rate-limited by the initial Ni(+) oxidative addition into either the C-CH₃ or C-C₂H₅ σ-bond in the butanone molecule. Ratios of integrated product ion intensities as well as the measured rate constants are used to determine values for each σ-bond activation rate constant. The lowest energy measurement presented in this study occurs when the binary complex ion possesses an internal energy of 16000 cm⁻¹. Under this condition, the Ni(+) assisted decomposition of the butanone molecule is rate limited by k(act)(C-C₂H₅) = (0.92 ± 0.08) × 10⁵ s⁻¹ and k(act)(C-CH₃) = (0.37 ± 0.03) × 10⁵ s⁻¹. The relative magnitudes of the two rate constants reflect the greater probability for reaction to occur along the C-C₂H₅ σ-bond insertion pathway, consistent with thermodynamic arguments. DFT calculations at the B3LYP/6-311++G(d,p) level of theory suggest the most likely geometries and relative energies of the reactants, intermediates, and products.

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Section: Methodscontrasting

confidence: 91%

Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

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Reaction Rate Constants and Mechanistic Detail of the Ni⁺+ Butanone Reaction

et al. 2011

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“…The studies, which have embraced Mg + attached to Ar, H 2 O, D 2 , N 2 , CO 2 , CH 4 , CH 2 O, and pyridine, have usually entailed exciting the 2 P r 2 S electronic transitions centered on the Mg + ion. [1][2][3][4][5] Recently, complexes such as Mg + -(H 2 O) n have also been probed through their infrared absorptions in the O-H stretch region. 6 In this paper, spectroscopic studies of charged complexes containing the magnesium cation are extended to include Mg + -H 2 and Mg + -D 2 , which are probed by using infrared (IR) photodissociation spectroscopy in the H-H and D-D stretch regions, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…Complexes containing the magnesium cation have played an important role in this program. The studies, which have embraced Mg + attached to Ar, H 2 O, D 2 , N 2 , CO 2 , CH 4 , CH 2 O, and pyridine, have usually entailed exciting the 2 P ← 2 S electronic transitions centered on the Mg + ion. − Recently, complexes such as Mg + −(H 2 O) n have also been probed through their infrared absorptions in the O−H stretch region …”

Section: Introductionmentioning

confidence: 99%

Infrared Spectra of Mass-Selected Mg⁺−H₂ and Mg⁺−D₂ Complexes

2008

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Rotationally resolved infrared spectra of Mg(+)-H(2) and Mg(+)-D(2) are recorded in the H-H (4025-4080 cm(-1)) and D-D (2895-2945 cm(-1)) stretch regions by monitoring Mg(+) photofragments. The nu(HH) and nu(DD) transitions of Mg(+)-H(2) and Mg(+)-D(2) are red-shifted by 106.2 +/- 1.5 and 76.0 +/- 0.1 cm(-1) respectively from the fundamental vibrational transitions of the free H(2) and D(2) molecules. The spectra are consistent with a T-shaped equilibrium structure in which the Mg(+) ion interacts with a slightly perturbed H(2) or D(2) molecule. From the spectroscopic constants, a vibrationally averaged intermolecular separation of 2.716 A (2.687 A) is deduced for the ground state of Mg(+)-H(2) (Mg(+)-D(2)), decreasing by 0.037 A (0.026 A) when the H(2) (D(2)) subunit is vibrationally excited.

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Gas‐Phase Cation Affinity and Basicity Scales

Laurence

Gal

2009

Lewis Basicity and Affinity Scales

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The study of the formation of complexes between cations and chemical species in the gas phase offers the unique possibility of measuring the intrinsic (i.e. free of solvent and counter ion influences) Lewis basicity of these species. Although the charge-transfer component of the interaction energy in cation adducts is normally smaller than the electrostatic and polarization components, gas-phase cations are generally considered as archetypal Lewis acids because the full positive charge of the naked cation allows strong binding with classical Lewis bases. In fact, almost any entity bearing some electron density, such as the rare gases, can form complexes with cations that may be observable in the gas phase.There is a large array of cations that have been studied in the gas phase for their interaction with Lewis bases (generally neutral organic molecules) and are still being actively investigated today. The most studied is the proton [1-6]. This special cation will not be dealt with in this chapter (however, see Section 1.3 in Chapter 1), since the proton and its transfer serve to define the Brönsted acids and bases, as opposed to Lewis acids and bases, which do not exchange protons. Moreover, although the proton and a cation with an empty orbital may be seen as identical from the point of view of the Lewis theory, the special 'electronic structure' of the proton (in fact the absence of any electron) makes the proton affinity and basicity scales completely different, qualitatively and quantitatively, from any other cation scales. A significant part of the studies of the interaction of gas-phase metal cations with organic molecules was devoted to their chemical reactivity: bond insertion, bond cleavage, elimination and so on. This aspect is not considered here, although some of these reactions may be used as indirect routes for the formation of cation/molecule adducts.Apart from the proton, experimental studies have focused primarily on the binding of alkali metal cations and transition metal monocations. Few studies have considered alkaline Lewis Basicity and Affinity Scales: Data and Measurement

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Spectroscopy and chemical dynamics of group II metal ion-formaldehyde complexes

Cited by 12 publications

References 52 publications

Reaction Rate Constants and Mechanistic Detail of the Ni⁺+ Butanone Reaction

Reaction Rate Constants and Mechanistic Detail of the Ni⁺+ Butanone Reaction

Infrared Spectra of Mass-Selected Mg⁺−H₂ and Mg⁺−D₂ Complexes

Gas‐Phase Cation Affinity and Basicity Scales

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Spectroscopy and chemical dynamics of group II metal ion-formaldehyde complexes

Cited by 12 publications

References 52 publications

Reaction Rate Constants and Mechanistic Detail of the Ni++ Butanone Reaction

Reaction Rate Constants and Mechanistic Detail of the Ni++ Butanone Reaction

Infrared Spectra of Mass-Selected Mg+−H2 and Mg+−D2 Complexes

Gas‐Phase Cation Affinity and Basicity Scales

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Reaction Rate Constants and Mechanistic Detail of the Ni⁺+ Butanone Reaction

Reaction Rate Constants and Mechanistic Detail of the Ni⁺+ Butanone Reaction

Infrared Spectra of Mass-Selected Mg⁺−H₂ and Mg⁺−D₂ Complexes