Periodic Trends Manifested through Gas-Phase Generation of Anions Such as [AlH4]-, [GaH4]-, [InH4]-, [SrH3]-, [BaH3]-, [Ba(0)(η2-O2CH)1]-, [Pb(0)H]-, [Bi(I)H2]-, and Bi- from Formates

Metal-hydride anions of main group elements, such as BaH₃ ^- and InH₄ ^-, were generated by dissociating formate adducts of the respective metal formates. Upon activation, these adducts fragment by formate-ion ejection or by decarboxylation. For adducts of alkali-metal formates, the formate-ion ejection is the preferred pathway, whereas for those of alkaline-earth and group 13-15 metals, the expulsion of CO₂ is the more favorable pathway. Decarboxylation is deemed to yield a metal-hydrogen bond presumably by a hydride transfer to the metal atom. For example, the decarboxylation of Al(η-OCOH)₄ ^- and Ga(η-OCOH)₄ ^- generated AlH₄ ^- and GaH₄ ^-, respectively. The initial fragment-ion with a H-M bond formed in this way from adducts of the heavier metals of group 13 (Ga, In, and Tl) undergo a unimolecular reductive elimination, ascribable to the "inert-pair" effect, to lower the metal-ion oxidation state from +3 to +1. As group 13 is descended, the tendency for this reductive elimination process increases. PbH₃ ^-, generated from the formate adduct of lead formate, reductively eliminated H₂ to form PbH^-, in which Pb is in oxidation state zero. In the energy-minimized structure [H-Pb(η²-H₂)]^-, proposed as an intermediate for the process, a H₂ molecule is coordinated with PbH^- as a dihapto ligand. The formate adducts of strontium and barium produce monoleptic ions such as [M(0)(η²-O₂CH)₁]^-, in which the formate ion is chelated to a neutral metal atom. The bismuth formate adduct undergoes a double reductive elimination process whereby the oxidation state of Bi is reduced from +3 to +1 and then to -1. Upon activation, the initially formed [H-Bi-H]^- ion transforms to an anionic η²-H₂ complex, which eliminates dihydrogen to form the bismuthide anion (Bi^-).

Dissociative iodomethane adsorption on Ag-MOR and the formation of AgI clusters: an ab initio molecular dynamics study

Using ab initio MD simulations, a full transformation path of iodomethane in Ag-MOR is explored: from adsorption to formation of AgI clusters.

Coinage Metal Hydrides: Synthesis, Characterization, and Reactivity

Hydride complexes of copper, silver, and gold encompass a broad array of structures, and their distinctive reactivity has enabled dramatic recent advances in synthesis and catalysis. This Review summarizes the synthesis, characterization, and key stoichiometric reactions of isolable or observable coinage metal hydrides. It discusses catalytic processes in which coinage metal hydrides are known or probable intermediates, and presents mechanistic studies of selected catalytic reactions. The purpose of this Review is to convey how developments in coinage metal hydride chemistry have led to new organic transformations, and how developments in catalysis have in turn inspired the synthesis of reactive new complexes.

Gas-phase VUV photoionisation and photofragmentation of the silver deuteride nanocluster [Ag10D8L6]2+ (L = bis(diphenylphosphino)methane). A joint experimental and theoretical study

The VUV photoionisation and photofragmentation of a mass-selected, ligated silver deuteride nanocluster was studied.

Synthesis and Spectroscopic Characterization of Diphenylargentate, [(C6H5)2Ag](.)

We present the structural and optical properties of the isolated diphenylargentate anion, which has been synthesized by multistage mass spectrometry in a quadrupole ion trap. The experimental photodetachment spectrum has been obtained by action spectroscopy. Comparison with quantum chemical calculations of the electronic absorption spectrum allows for a precise characterization of the spectroscopic features, showing that in the low-energy regime, the optical properties of diphenylargentate bear a significant resemblance to those of atomic silver.

Gas-phase synthesis of hydrodiphenylcyclopropenylium via nonclassical Favorskii rearrangement from alkali-cationized alpha,alpha'-dibromodibenzyl ketone

The gas-phase synthesis of hydrodiphenylcyclopropenylium from alkali-cationized alpha,alpha'-dibromodibenzyl ketone (1) via nonclassical Lewis-acid-induced Favorskii rearrangement has been studied by electrospray ionization/tandem mass spectrometry (ESI-MS/MS) and theoretical methods, showing that cations [1-Br](+) by debromination from 1 and 1.M(+)(M = Li or Na) by alkali-metal cationization of 1 could convert into the protonated diphenylcyclopropenone 2.H(+) by collision-induced dissociation in the gas phase. A concerted mechanism for the Lewis-acid-induced Favorskii rearrangement from alkali-metal-cationized alpha,alpha'-dibromodibenzyl ketone was proposed and studied, based on mass spectrometric results and theoretical methods.

Comparison of collision- versus electron-induced dissociation of sodium chloride cluster cations

The collision-induced dissociation (CID) and electron-induced dissociation (EID) spectra of the [(NaCl)(m)(Na)(n)](n+) clusters of sodium chloride have been examined in a hybrid linear ion trap Fourier transform ion cyclotron resonance mass spectrometer. For singly charged cluster ions (n = 1), mass spectra for CID and EID of the precursor exhibit clear differences, which become more pronounced for the larger cluster ions. Whereas CID yields fewer product ions, EID produces all possible [(NaCl)(x)Na](+) product ions. In the case of doubly charged cluster ions, EID again leads to a larger variety of product ions. In addition, doubly charged product ions have been observed due to loss of neutral NaCl unit(s). For example, EID of [(NaCl)(11)(Na)(2)](2+) leads to formation of [(NaCl)(10)(Na)(2)](2+), which appears to be the smallest doubly charged cluster of sodium chloride observed experimentally to date. The most abundant product ions in EID spectra are predominantly magic number cluster ions. Finally, [(NaCl)(m)(Na)(2)](+*) radical cations, formed via capture of low-energy electrons, fragment via the loss of [(NaCl)(n)(Na)](*) radical neutrals.