How to search for and reveal a hidden intermediate? The ELF topological description of non-synchronicity in double proton transfer reactions under oriented external electric field.

Context: The nature of double intermolecular proton transfer was studied with the ELF topological approach in two model dimers (the formic acid homodimer and the 1,2,3-triazole-guanidine heterodimer) under an oriented external electric field. It has been shown that each of the two dimers can have either a one-step (one transition state structure) or two-step (two transition state structures) reaction path, depending on the intensity and orientation of the external electric field. The presence of a singularly broad shoulder (plateau in the case of homodimer and plateau-like for heterodimer) around the formal transition state structure results from the strong asynchronicity of the reaction.

Microsolvation of cobalt, nickel, and copper atoms with ammonia: a theoretical study of the solvated electron precursors.

Context: The s-block metals dissolved in ammonia form metal-ammonia complexes with diffuse electrons which could be used for redox catalysis. In this theoretical paper, we investigated the possibility of the d-bloc transition metals (Mn, Fe, Co, Ni, and Cu) solvated by ammonia. It has been demonstrated that both Mn and Fe atoms undergo into an oxidative reaction with NH forming an inserted species, HMNH.

A two-electron reducing reaction of CO to an oxalate anion: a theoretical study of delocalized (presolvated) electrons in Al(CH)(NH), = 0-2 and = 1-6, clusters.

Presolvated electron possibility in three oxidation states of aluminum - Al(0), Al(I), and Al(II) - has been theoretically investigated for the Al + 6NH, Al(CH) + 5NH, and Al(CH) + 4NH reactions. It has been shown that the metal center adopts a tetrahedral shape for its most stable geometric structure, irrespective of the degree of Al oxidation states. Using different analysis techniques (highest occupied molecular orbital shapes, spin density distributions, and electron delocalization ranges), we showed that presolvated (delocalized) electrons are only formed in the Al(CH)(NH) coordination complexes when 2 ≤ ≤ 4.

Unimolecular decomposition of methyl ketene and its dimer in the gas phase: theory and experiment.

We present a combined theoretical and experimental investigation on the single photoionization and dissociative photoionization of gas-phase methyl ketene (MKE) and its neutral dimer (MKE2). The performed experiments entail the recording of photoelectron photoion coincidence (PEPICO) spectra and slow photoelectron spectra (SPES) in the energy regime 8.7-15.

What is the hydrophobic interaction contribution to the stabilization of micro-hydrated complexes of trimethylamine oxide (TMAO)? A joint DFT-D, QTAIM, and MESP study.

Micro-hydrated trimethylamine oxide (TMAO) has been investigated using a range-separated-hybrid functional including empirical dispersion correction. Electrophilic and nucleophilic sites on TMAO and water clusters have been identified using the molecular electrostatic potential (MESP). The nature of the chemical bonding in the different isomers of the micro-hydrated complexes has been investigated with the topological analysis of the electron density (QTAIM) method.

Dehydrocoupling of dimethylamine borane by titanocene: elucidation of ten years of inconsistency between theoretical and experimental descriptions.

More than ten years ago, Manners and coworkers published the first experimental study on the efficiency of titanocene to catalyze the dehydrocoupling of dimethylamine borane (DMAB, T. Clark, C. Russell and I.

A Theoretical Study of HF-CHCl and (HF)-CHCl Complexes.

The equilibrium geometries, relative stabilities, and vibrational properties (frequencies and intensities) of the HF-CHCl (1:1) and (HF)-CHCl (1:2) complexes were reinvestigated at the MP2/Aug-cc-pVTZ level. The results are discussed in light of the results obtained in solid argon matrices by L. Andrews and co-workers and related to the bonding analysis.

Characterization of B-H agostic compounds involved in the dehydrogenation of amine-boranes by group 4 metallocenes.

For over a decade, amine-borane has been considered as a potential chemical hydrogen vector in the context of a search for cleaner energy sources. When catalyzed by organometallic complexes, the reaction mechanisms currently considered involve the formation of β-BH agostic intermediates. A thorough understanding of these intermediates may constitute a crucial step toward the identification of ideal catalysts.

Topological analysis of the reaction of uranium ions (U+, U2+) with N2O in the gas phase.

Density functional theory calculations were performed to study the ability of uranium cations, U(+) and U(2+), to activate the N-N and N-O bonds of N(2)O. A close description of the reaction pathways leading to different reaction products is presented. The obtained results are compared with previous experimental works.

The Ni2+O2 reaction: the IR spectrum and structure of Ni2O2. A combined IR matrix isolation and theoretical study.

The formation of Ni2O2 can be observed from the condensation of effusive beams of Ni and O2 in neon or argon matrices. Observation of 58Ni(2)16O2, 58Ni60Ni16O2, 60Ni2(16)O2, Ni(2)18O2 and Ni(2)16O18O isotopic data for five fundamental transitions enable a discussion of structural parameters for matrix-isolated Ni2O2 in its cyclic ground state. Analysis of the nickel isotopic effects on the 58,60Ni2(16)O18O fundamentals suggest an elongated rhombic structure with a Ni-O bond force constant (240+/-10 N m-1) and NiONi bond angles around 79 degrees.

Comparative study of the bonding in the first series of transition metal 1:1 complexes M-L (M = Sc, ..., Cu; L = CO, N(2), C(2)H(2), CN(-), NH(3), H(2)O, and F(-)).

The nature of the chemical bonding in the 1:1 complexes formed by the fourth period transition metals (Sc, ...

The Ni + O2 reaction: a combined IR matrix isolation and theoretical study of the formation and structure of NiO2.

The reaction of Ni atoms with molecular oxygen has been reinvestigated experimentally in neon matrices and theoretically at the DFT PW91PW91/6311G(3df) level. Experimental results show that i) the nature of the ground electronic state of the superoxide metastable product is the same in neon and argon matrices, ii) two different photochemical pathways exist for the conversion of the superoxide to the dioxide ground state (involving 1.6 or 4 eV photons) and iii) an important matrix effect exists in the Ni + O(2)--> Ni(O(2)) or ONiO branching ratios.

Energetic and topological analyses of the oxidation reaction between Mo(n) (n = 1, 2) and N2O.

The interaction between molybdenum, atom, and dimer, with nitrous oxide has been investigated using density functional theory. The analysis of the potential energy surfaces for both reactions has revealed that a single molybdenum atom can activate the N--O bond of N2O requiring a small activation energy. However, the presence of several intersystem crossings between three different spin states, namely, septet, quintet and triplet states, seems to be the major constraint to the Mo + N2O reaction.

Theoretical study of structure, stability and infrared spectra of CH3X-SO3 (X = F, Cl, Br) complexes.

Ab initio computational study of the electronic structure and infrared spectra of donor-acceptor complexes formed between SO3 and CH3X (X = F, Cl, Br) molecules was carried out at the MP2(full)/6-31G(d) level of theory. The calculated complexation energy at G2MP2 level shows that stability of complexes decrease, as CH3Cl-SO3 > CH3Br-SO3 > CH3F-SO3. The NBO partitioning scheme show that the lengthening of the C-F, C-Cl, and C-Br bond lengths, upon complexation, is due to an decreasing "s" character in these bonds.

Energetic and topological analysis of the reaction of Mo and Mo2 with NH3, C2H2, and C2H4 molecules.

The Density functional theory has been applied to characterize the structural features of Mo(1,2)-NH(3),-C(2)H(4), and -C(2)H(2) compounds. Coordination modes, geometrical structures, and binding energies have been calculated for several spin multiplets. It has been shown that in contrast to the conserved spin cases (Mo(1,2)-NH(3)), the interaction between Mo (or Mo(2)) and C(2)H(4) (or C(2)H(2)) are the low-spin (Mo-C(2)H(4) and -C(2)H(2)) and high-spin (Mo(2)-C(2)H(4) and -C(2)H(2)) complexes.