Metal-to-Ligand Charge Transfer in the Gas-Phase Cluster Limit

Spence, Thomas G.; Trotter, Brett T.; Burns, Thomas D.; Posey, Lynmarie A.

doi:10.1021/jp982335x

Cited by 43 publications

(41 citation statements)

References 44 publications

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“…This effect is reflected in the nonzero y-intercepts of these kinetic data. The extent of dissociation prior to the application of the SORI waveform is the largest for Ba 2+ (H 2 O) 7 and decreases with decreasing metal ionic radius. To measure the SORI-CAD kinetics, an average center-of-mass collision energy of 0.59 kcal/mol and an average collision frequency of 25 s −1 were used.…”

Section: Collisionally Activated Dissociation Kineticsmentioning

confidence: 99%

“…The first measurements of the binding energy for inner-shell water molecules attached to a divalent metal were recently reported by Rodriguez-Cruz et al for Ni 2+ (H 2 O) 6-8 and Ca 2+ (H 2 O) [5][6][7] ions. 6a The measured values for calcium are in good agreement with the B3LYP-calculated values of Pavlov et al 2c and also with subsequent enthalpy values measured by Kebarle and co-workers.…”

Section: Introductionmentioning

confidence: 99%

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Hydration Energies and Structures of Alkaline Earth Metal Ions, M²⁺(H₂O)_n, n = 5−7, M = Mg, Ca, Sr, and Ba

1999

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The evaporation of water from hydrated alkaline earth metal ions, produced by electrospray ionization, was studied in a Fourier transform mass spectrometer. Zero-pressure-limit dissociation rate constants for loss of a single water molecule from the hydrated divalent metal ions, M 2+ (H 2 O) n (M = Mg, Ca, and Sr for n = 5-7, and M = Ba for n = 4-7), are measured as a function of temperature using blackbody infrared radiative dissociation. From these values, zero-pressurelimit Arrhenius parameters are obtained. By modeling the dissociation kinetics using a master equation formalism, threshold dissociation energies (E o ) are determined. These reactions should have a negligible reverse activation barrier; therefore, E o values should be approximately equal to the binding energy or hydration enthalpy at 0 K. For the hepta-and hexahydrated ions at low temperature, binding energies follow the trend expected on the basis of ionic radii: Mg > Ca > Sr > Ba. For the hexahydrated ions at high temperature, binding energies follow the order Ca > Mg > Sr > Ba. The same order is observed for the pentahydrated ions. Collisional dissociation experiments on the tetrahydrated species result in relative dissociation rates that directly correlate with the size of the metals. These results indicate the presence of two isomers for hexahydrated magnesium ions: a lowtemperature isomer in which the six water molecules are located in the first solvation shell, and a high-temperature isomer with the most likely structure corresponding to four water molecules in the inner shell and two water molecules in the second shell. These results also indicate that the pentahydrated magnesium ions have a structure with four water molecules in the first solvation shell and one in the outer shell. The dissociation kinetics for the hexa-and pentahydrated clusters of Ca 2+ , Sr 2+ , and Ba 2+ are consistent with structures in which all the water molecules are located in the first solvation shell.

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Section: Collisionally Activated Dissociation Kineticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hydration Energies and Structures of Alkaline Earth Metal Ions, M²⁺(H₂O)_n, n = 5−7, M = Mg, Ca, Sr, and Ba

1999

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“…The lack of data stems mainly from the difficulty of producing these species in the gas phase. However, several groups have been successful; Posey and co-workers have used electrospray to prepare size selected Fe(II)-polypyridine complexes with different numbers of polar, organic solvents, such as acetone, methanol and DMSO [8][9][10]. They studied the influence of successive solvation on the known Fe(II)-polypyridine metal-to-ligand charge transfer (MLCT) process using laser photofragmentation mass spectrometry and made comparisons with condensed phase data.…”

Section: Introductionmentioning

confidence: 99%

UV photofragmentation of gas phase M and M2 complexes with ketones, where M = Cu and Ag

Puškar

Stace

2005

Molecular Physics

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Results are reported of an experimental study of the UV photofragmentation patterns of singly and doubly charged complexes consisting of either copper or silver in association with a series of ketones. Considerable variation is seen in response to photoexcitation, ranging from extensive chemical reactivity in the case of Cu þ through to no evidence of photoabsorption on the part of Ag 2þ complexes. It is concluded that the close proximity of a charge has a considerable influence on energy of the non-bonding electrons of the carbonyl group in the ketones, and that this, in turn, influences the * n electronic transition promoted at UV wavelengths.

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“…Similar experimental arrangements have been reported elsewhere for slightly different purposes; Posey was able to heavily solvate transition metals in the gas-phase by introducing an auxiliary source of solventladen dinitrogen at the electrospray source [42]. A variety of solvents, including DMSO and DMF, typically unsuitable for ESI-MS [43], could be vaporized and introduced to gas-phase ions for analysis in a tandem mass spectrometer [44]. The exact experimental details are not revealed, but since we are able to reproduce their results on our instrumental set-up suggests the two systems are likely to be similar.…”

Section: Resultsmentioning

confidence: 74%

Gas-phase reactivity of ruthenium carbonyl cluster anions

Henderson

Kwok

McIndoe

2008

J. Am. Soc. Mass Spectrom.

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Partially-ligated anionic ruthenium carbonyl clusters react with alkenes, arenes, and alkanes in the gas phase; the products undergo extensive C-H activation and lose dihydrogen and carbon monoxide under collision-induced dissociation conditions. Triethylsilane and phenylsilane are also reactive towards the unsaturated clusters, and oxygen was shown to rapidly break down the cluster core by oxidative cleavage of the metal-metal bonds. These qualitative gas-phase reactivity studies were conducted using an easily-installed and inexpensive modification of a commercial electrospray ionization mass spectrometer. Interpretation of the large amounts of data generated in these studies is made relatively straightforward by employing energydependent electrospray ionization mass spectrometry (EDESI-MS). here are many examples of reactions between molecules and metal cluster ions in the gas phase, and the area has been well reviewed [1,2]. Of intense current interest are those systems in which catalytic reactions (homogeneous or heterogeneous) are modeled [3,4]. The information gleaned from these studies is particularly advantageous in systems where little or nothing is known about reactivity. Interest in the area stems from the fact that the chemistry of highly reactive, metallic nanoparticles is fundamentally difficult to study, and it is high surface area metals and metal oxides that are responsible for the most industrially important heterogeneous catalytic reactions. Any means of gaining insight into the mechanism of these reactions may prove useful in designing more efficient and more selective catalysts. The absence of surfaces, solvents, and counterions make the gas phase a considerably less complicated environment than that found in solution. Just how good the correspondence is between gas-phase and solution results is subject to active debate [5][6][7], but there is little argument that the gas phase benefits from the reduction in the number of variables, especially when dealing with complicated systems. The gas-phase reactivity of a wide variety of partially ligated clusters have been studied, including oxides [8 -11] [18]. and even some mixed species [19,20]. However, for the most part, the extent of ligation is low and, correspondingly, so is the relevance to solution chemistry. Homogeneous catalysis is generally performed under conditions that are relatively mild and in which the catalysts maintain a (near) complete coordination sphere, so the comparison with nearly naked gas-phase metal clusters is somewhat tenuous (though interestingly, may more closely approximate the conditions of heterogeneous catalysis, which frequently involves unligated metal particles on a surface) [21,22].Some work has also been done on partially ligated carbonyl clusters; an early paper by Ridge [23] example by Ridge demonstrated that in a Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS), partially ligated cationic transition-metal carbonyl clusters generated by electron ionization reacted readily with cycl...

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Metal-to-Ligand Charge Transfer in the Gas-Phase Cluster Limit

Cited by 43 publications

References 44 publications

Hydration Energies and Structures of Alkaline Earth Metal Ions, M²⁺(H₂O)_n, n = 5−7, M = Mg, Ca, Sr, and Ba

Hydration Energies and Structures of Alkaline Earth Metal Ions, M²⁺(H₂O)_n, n = 5−7, M = Mg, Ca, Sr, and Ba

UV photofragmentation of gas phase M and M2 complexes with ketones, where M = Cu and Ag

Gas-phase reactivity of ruthenium carbonyl cluster anions

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Metal-to-Ligand Charge Transfer in the Gas-Phase Cluster Limit

Cited by 43 publications

References 44 publications

Hydration Energies and Structures of Alkaline Earth Metal Ions, M2+(H2O)n, n = 5−7, M = Mg, Ca, Sr, and Ba

Hydration Energies and Structures of Alkaline Earth Metal Ions, M2+(H2O)n, n = 5−7, M = Mg, Ca, Sr, and Ba

UV photofragmentation of gas phase M and M2 complexes with ketones, where M = Cu and Ag

Gas-phase reactivity of ruthenium carbonyl cluster anions

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Product

Resources

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Hydration Energies and Structures of Alkaline Earth Metal Ions, M²⁺(H₂O)_n, n = 5−7, M = Mg, Ca, Sr, and Ba

Hydration Energies and Structures of Alkaline Earth Metal Ions, M²⁺(H₂O)_n, n = 5−7, M = Mg, Ca, Sr, and Ba