Water activation and splitting by single anionic iridium atoms.

Mass spectrometric analysis of anionic products that result from interacting Ir with HO shows the efficient generation of [Ir(HO)] complexes and IrO molecular anions. Anion photoelectron spectra of [Ir(HO)], formed under various source conditions, exhibit spectral features that are due to three different forms of the complex: the solvated anion-molecule complex, Ir(HO), as well as the intermediates, [H-Ir-OH] and [H-Ir-O], where one and two O-H bonds have been broken, respectively. The measured and calculated vertical detachment energy values are in good agreement and, thus, support identification of all three types of isomers.

Theoretical and Experimental Study of the Spectroscopy and Thermochemistry of UC.

A combination of high-level calculations and anion photoelectron detachment (PD) measurements is reported for the UC, UC, and UC molecules. To better compare the theoretical values with the experimental photoelectron spectrum (PES), a value of 1.493 eV for the adiabatic electron affinity (AEA) of UC was calculated at the Feller-Peterson-Dixon (FPD) level.

Electronic Properties of UN and UN from Photoelectron Spectroscopy and Correlated Molecular Orbital Theory.

The results of calculations of the properties of the anion UN including electron detachment are described, which further expand our knowledge of this diatomic molecule. High-level electronic structure calculations were conducted for the UN and UN diatomic molecules and compared to photoelectron spectroscopy measurements. The low-lying Ω states were obtained using multireference CASPT2 including spin-orbit effects up to ∼20,000 cm.

Experimental and Computational Description of the Interaction of H and H with U.

The results of ab initio correlated molecular orbital theory electronic structure calculations for low-lying electronic states are presented for UH and UH and compared to photoelectron spectroscopy measurements. The calculations were performed at the CCSD(T)/CBS and multireference CASPT2 including spin-orbit effects by the state interacting approach levels. The ground states of UH and UH are predicted to be Ι and Λ, respectively.

Molecular-level electrocatalytic CO reduction reaction mediated by single platinum atoms.

The activation and transformation of HO and CO mediated by electrons and single Pt atoms is demonstrated at the molecular level. The reaction mechanism is revealed by the synergy of mass spectrometry, photoelectron spectroscopy, and quantum chemical calculations. Specifically, a Pt atom captures an electron and activates HO to form a H-Pt-OH complex.

Metal-Metal Bonding in Actinide Dimers: U and U.

Understanding direct metal-metal bonding between actinide atoms has been an elusive goal in chemistry for years. We report for the first time the anion photoelectron spectrum of U. The threshold of the lowest electron binding energy (EBE) spectral band occurs at 1.

The electron affinity of the uranium atom.

The results of a combined experimental and computational study of the uranium atom are presented with the aim of determining its electron affinity. Experimentally, the electron affinity of uranium was measured via negative ion photoelectron spectroscopy of the uranium atomic anion, U. Computationally, the electron affinities of both thorium and uranium were calculated by conducting relativistic coupled-cluster and multi-reference configuration interaction calculations.

Ligated aluminum cluster anions, LAl ( = 1-14, L = N[Si(Me)]).

A wide range of low oxidation state aluminum-containing cluster anions, LAln- (n = 1-14, L = N[Si(Me)3]2), were produced via reactions between aluminum cluster anions and hexamethyldisilazane (HMDS). These clusters were identified by mass spectrometry, with a few of them (n = 4, 6, and 7) further characterized by a synergy of anion photoelectron spectroscopy and density functional theory (DFT) based calculations. As compared to a previously reported method which reacts anionic aluminum hydrides with ligands, the direct reactions between aluminum cluster anions and ligands promise a more general synthetic scheme for preparing low oxidation state, ligated aluminum clusters over a large size range.

Study of the Reaction of Hydroxylamine with Iridium Atomic and Cluster Anions ( = 1-5).

Elucidating the multifaceted processes of molecular activation and subsequent reactions gives a fundamental view into the development of iridium catalysts as they apply to fuels and propellants, for example, for spacecraft thrusters. Hydroxylamine, a component of the well-known hydroxylammonium nitrate (HAN) ionic liquid, is a safer alternative and mimics the chemistry and performance standards of hydrazine. The activation of hydroxylamine by anionic iridium clusters, Ir ( = 1-5), depicts a part of the mechanism, where two hydrogen atoms are removed, likely as H, and Ir(NOH) clusters remain.

Simultaneous Functionalization of Methane and Carbon Dioxide Mediated by Single Platinum Atomic Anions.

Mass spectrometric analysis of the anionic products of interaction among Pt, methane, and carbon dioxide shows that the methane activation complex, HC-Pt-H, reacts with CO to form [HC-Pt-H(CO)]. Two hydrogenation and one C-C bond coupling products are identified as isomers of [HC-Pt-H(CO)] by a synergy between anion photoelectron spectroscopy and quantum chemical calculations. Mechanistic study reveals that both CH and CO are activated by the anionic Pt atom and that the successive depletion of the negative charge on Pt drives the CO insertion into the Pt-H and Pt-C bonds of HC-Pt-H.

Photoelectron spectroscopic study of dipole-bound and valence-bound nitromethane anions formed by Rydberg electron transfer.

Close-lying dipole-bound and valence-bound states in the nitromethane anion make this molecule an ideal system for studying the coupling between these two electronically different states. In this work, dipole-bound and valence-bound nitromethane anions were generated by Rydberg electron transfer and characterized by anion photoelectron spectroscopy. The presence of the dipole-bound state was demonstrated through its photoelectron spectral signature, i.

Mapping the Electronic Structure of the Uranium(VI) Dinitride Molecule, UN.

A combined anion photoelectron spectroscopic and relativistic coupled-cluster computational study of the electronic structure of the UN molecule is presented. Because the photoelectron spectrum of the uranium dinitride negative ion, UN, directly reflects the electronic structure of neutral UN, we have measured and relied upon the photoelectron spectrum of the UN anion as a means of mapping the electronic structure of neutral UN. In addition to the electron affinity of the UN ground state, energy levels of the UN excited states were well characterized by the close interplay between the experiment and high-level theory.

Reply to the Comment on "Realization of Lewis Basic Sodium Anion in the NaBH Cluster".

We reply to the comment by S. Pan and G. Frenking who challenged our interpretation of the Na :→BH dative bond in the recently synthesized NaBH cluster.

Excess electrons bound to HS trimer and tetramer clusters.

We have prepared the hydrogen sulfide trimer and tetramer anions, (HS) and (HS), measured their anion photoelectron spectra, and applied high-level quantum chemical calculations to interpret the results. The sharp peaks at low electron binding energies in their photoelectron spectra and their diffuse Dyson orbitals are evidence for them both being dipole-bound anions. While the dipole moments of the neutral (HS) and (HS) clusters are small, the excess electron induces structural distortions that enhance the charge-dipolar attraction and facilitate the binding of diffuse electrons.

"Outlaw" Dipole-Bound Anions of Intra-Molecular Complexes.

Using the example of silatranes XSi(OCHCH)N (X = Me, H, F, Cl), , it was found that the effect of the dipole-bound (DB) electron on the cage intramolecular complexes does not fit into the standard views. Upon the transition from to the DB anions , the unusual shortening of the internuclear Si···N distance is always observed. For X = Cl, it is equal to 0.

The ground state, quadrupole-bound anion of succinonitrile revisited.

Using a combination of Rydberg electron transfer and negative ion photoelectron spectroscopy, we revisited an earlier study which, based on several separate pieces of evidence, had concluded that trans- and gauche-succinonitrile can form quadrupole bound anions (QBAs) and dipole bound anions (DBAs), respectively. In the present work, succinonitrile anions were formed by Rydberg electron transfer and interrogated by negative ion photoelectron spectroscopy. The resulting anion photoelectron spectra exhibited distinctive spectral features for both QBA and DBA species in the same spectrum, thereby providing direct spectroscopic confirmation of previous indirect conclusions.

Observation of the dipole- and quadrupole-bound anions of 1,4-dicyanocyclohexane.

Quadrupole-bound anions are negative ions in which their excess electrons are loosely bound by long-range electron-quadrupole attractions. Experimental evidence for quadrupole-bound anions has been scarce; until now, only trans-succinonitrile had been experimentally confirmed to form a quadrupole-bound anion. In this study, we present experimental evidence for a new quadrupole-bound anion.

Realization of Lewis Basic Sodium Anion in the NaBH Cluster.

We report a Na: →B dative bond in the NaBH cluster, which was designed on the principle of minimum-energy rupture, prepared by laser vaporization, and characterized by a synergy of anion photoelectron spectroscopy and electronic structure calculations. The global minimum of NaBH features a Na-B bond. Its preferred heterolytic dissociation conforms with the IUPAC definition of dative bond.

Spectroscopic Measurement of a Halogen Bond Energy.

Halogen bonding (XB) has emerged as an important bonding motif in supramolecules and biological systems. Although regarded as a strong noncovalent interaction, benchmark measurements of the halogen bond energy are scarce. Here, a combined anion photoelectron spectroscopy and density functional theory (DFT) study of XB in solvated Br anions is reported.

The metallo-formate anions, M(CO), M = Ni, Pd, Pt, formed by electron-induced CO activation.

The metallo-formate anions, M(CO), M = Ni, Pd, and Pt, were formed by electron-induced CO activation. They were generated by laser vaporization and characterized by a combination of mass spectrometry, anion photoelectron spectroscopy, and theoretical calculations. While neutral transition metal atoms are normally unable to activate CO, the addition of an excess electron to these systems led to the formation of chemisorbed anionic complexes.

The correlation-bound anion of p-chloroaniline.

The p-chloroaniline anion was generated by Rydberg electron transfer and studied via velocity-map imaging anion photoelectron spectroscopy. The vertical detachment energy (VDE) of the p-chloroaniline anion was measured to be 6.6 meV.

Selective Activation of the C-H Bond in Methane by Single Platinum Atomic Anions.

Mass spectrometric analysis of the anionic products of interaction between platinum atomic anions, Pt , and methane, CH and CD , in a collision cell shows the preferred generation of [PtCH ] and [PtCD ] complexes and a low tendency toward dehydrogenation. [PtCH ] is shown to be H-Pt-CH by a synergy between anion photoelectron spectroscopy and quantum chemical calculations, implying the rupture of a single C-H bond. The calculated reaction pathway accounts for the observed selective activation of methane by Pt .

Tuning the electronic properties of hexanuclear cobalt sulfide superatoms ligand substitution.

Molecular clusters are attractive superatomic building blocks for creating materials with tailored properties due to their unique combination of atomic precision, tunability and functionality. The ligands passivating these superatomic clusters offer an exciting opportunity to control their electronic properties while preserving their closed shells and electron counts, which is not achievable in conventional atoms. Here we demonstrate this concept by measuring the anion photoelectron spectra of a series of hexanuclear cobalt sulfide superatomic clusters with different ratios of electron-donating and electron-withdrawing ligands, CoS(PEt) (CO) ( = 0-3).

Communication: Water activation and splitting by single metal-atom anions.

We report experimental and computational results pertaining to the activation and splitting of single water molecules by single atomic platinum anions. The anion photoelectron spectra of [Pt(HO)], formed under different conditions, exhibit spectral features that are due to the anion-molecule complex, Pt(HO), and to the reaction intermediates, HPtOH and HPtO, in which one and two O-H bonds have been broken, respectively. Additionally, the observations of PtO and H in mass spectra strongly imply that water splitting via the reaction Pt + HO → PtO + H has occurred.