Addition and elimination reactions of \H2\ in ruthenaborane clusters: A computational study

International audienceRuthenaborane clusters have been modelled by performing density functional theory calculations using the \B3LYP\ functional. The calculations gain insights into hydrogen storage and the H-H bond activation by ruthenaboranes. To study the nature of the chemical bond of \H2\ molecules attached to ruthenaboranes, we carried out structural optimizations for different ruthenaborane clusters and determined transition state structures for their hydrogenation addition/elimination reactions. Calculations of the reaction pathways yielded different transition-state structures involving molecular hydrogen bonded to the cluster or formation of metal hydrides. The H-H bond of \H2\ seems to be activated by the ruthenaborane clusters as activation energies of 24-42 kcal/mol were calculated for the \H2\ addition reaction. The calculated Gibbs free energy for the \H2\ addition reaction is 14-27 kcal/mol. The calculated activation energies and the molecular structures of the [(C5Me5)Ru2B10H16], [(C5Me5)Ru2B8H14] and [(C5Me5)Ru2B8H12] clusters with different degree of hydrogenation are compared. The mechanisms of the \H2\ addition and elimination reactions of the studied clusters suggest that they might be useful as hydrogen storage materials due to their ability to activate the H-H bond. They also serve as an example of the ability of hypoelectronic metallaboranes to reversibly or irreversibly bind hydrogen

Disproportionation of Gold(II) Complexes. A Density Functional Study of Ligand and Solvent Effects

This article discusses disproportionation of gold(II) as an atomic ion as well as with chloride and neutral ligands

Can high-hydride content hypoelectronic rhenaborane clusters take up dihydrogen? a theoretical study

DFT calculations were performed to gain insight of possible dihydrogen uptake by the electron-deficient metallaborane (CpRe)2B6H6 (A). Results first revealed a possible H–H insertion in A, giving rise to the formation of (CpRe)2B6H8 isomers accompanied with an opening of B–B bonds in the B6H6 ring and Re–B bonds breaking. A two-step pathway was calculated to be the lowest-energy route with the highest activation barrier at ca. 25 kcal/mol at the B3LYP/6-311G++(d,p) level of theory. Addition of a second dihydrogen molecule to A is also found possible leading to the hydrogen-saturated species (CpRe)2B6H10

A Theoretical Investigation of Bonding and Electron Counting in Compounds Structurally Related to Ti5Te4

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Periodic and Molecular Modeling Study of Donor - Acceptor Interactions in (dbbpy)Pt(tdt) • TENF and [Pt(dbbpy)(tdt)]₂ • TENF

This article discusses a periodic and molecular modeling study. Supramolecular stacked materials (dbbpy)Pt(tdt)•TENF and [Pt(dbbpy)(tdt)]₂•TENF are built from (dbbpy)Pt(tdt) donors (D) with TENF acceptors (A) (TENF = 2,4,5,7-tetranitro-9-fluorenone; dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine; tdt = 3,4-toluenedithiolate)

Binary Donor–Acceptor Adducts of Tetrathiafulvalene Donors with Cyclic Trimetallic Monovalent Coinage Metal Acceptors

Reactions between the π-acidic cyclic trimetallic coinage metal(I) complexes {[Cu(μ-3,5-(CF3)2pz)]3, {[Ag(μ-3,5-(CF3)2pz)]3, and {[Au(μ-3,5-(CF3)2pz)]3 with TTF, DBTTF and BEDT-TTF give rise to a series of coinage metal(I)-based new binary donor-acceptor adducts {[Cu(μ-3,5-(CF3)2pz)]3DBTTF} (1), {[Ag(μ-3,5-(CF3)2pz)]3DBTTF} (2), {[Au(μ-3,5-(CF3)2pz)]3DBTTF} (3), {[Cu(μ-3,5-(CF3)2pz)]3TTF} (4), {[Ag(μ-3,5-(CF3)2pz)]3TTF} (5), {[Au(μ-3,5-(CF3)2pz)]3TTF} (6), {[Cu(μ-3,5-(CF3)2pz)]3BEDT-TTF} (7), {[Ag(μ-3,5-(CF3)2pz)]3BEDT-TTF} (8), and {[Au(μ-3,5-(CF3)2pz)]3BEDT-TTF} (9), where pz = pyrazolate, TTF = tetrathiafulvalene, DBTTF = dibenzotetrathiafulvalene, and BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene. This series of binary donor-acceptor adducts has been found to exhibit remarkable supramolecular structures in both the solid state and solution, whereby they exhibit supramolecular stacked chains and oligomers, respectively. The supramolecular solid-state and solution binary donor-acceptor adducts also exhibit superior shelf stability under ambient laboratory storage conditions. Structural and other electronic properties of solids and solutions of these adducts have been characterized by single-crystal X-ray diffraction (XRD) structural analysis, 1H and 19F NMR, UV-vis-near-IR spectroscopy, Fourier transform infrared, and computational investigations. The combined results of XRD structural data analysis, spectroscopic measurements, and theoretical studies suggest sustenance of the donor-acceptor stacked structure and electronic communication in both the solid state and solution. These properties are discussed in terms of potential applications for this new class of supramolecular binary donor-acceptor adducts in molecular electronic devices, including solar cells, magnetic switching devices, and field-effect transistors