On the asymmetry in molybdenum–oxygen bonding in the MoO3 structure: ETS–NOCV analysis

Abstract

In the present study, the analysis of natural orbitals for chemical valence (NOCV) combined with the extended-transition-state (ETS) bond-energy decomposition method (ETS-NOCV) was applied to characterize an asymmetry in Mo-O bonding in MoO 3 crystal. Considered were three non-equivalent oxygen sites (O1, O2, O3) in the Mo 7 O 30 H 18 cluster model of (010) surface of MoO 3 . The ETS-NOCV method leads to the conclusion that an increase in the Mo-O distances, from 1.68 Å (for Mo-O1), through 1.73 Å (for Mo-O2), up to 1.94 Å (for Mo-O3), is directly related to decrease in strength of both r-and p-contributions of Mo-O bond. Further, Mo-O connection appeared to exhibit both ionic (the charge transfer from 2p orbital of oxygen to molybdenum) and the covalent (charge accumulation in the region of Mo-O) components. Finally, the trend in the orbital energy stabilization (DE orb ) originating from the dominant r-and p-bond contributions appeared to correlate very well with the oxygen-vacancy formation energies published earlier by Tokarz-Sobieraj et al. (Surf Sci 489:107, 2001).

Direct conversion of multilayer molybdenum trioxide to nanorods as multifunctional electrodes in lithium-ion batteries

“…Hence, particle fragmentation resulted from the capture of particles inside zones experiencing strong stress when the two grinding beads collided (frontal collisions in straining regions or oblique collisions induced by a local shear). 1,34 The pulling force readily disrupted the weak van der Waals interactions between layers, resulting in a single layer, or a few layers, of smaller size being peeled away. On the other hand, if fractional forces exceeded the mechanical strength of the sheet along the preferred [001] direction, energy-minimization favored one-dimensional shapes, as observed in microscopy images [Scheme 1 and Fig.…”

A Quantitative Description of the σ‐Donor and π‐Acceptor Properties of Substituted Phenanthrolines

“…Furthermore, when NOCV is associated with an energy decomposition analysis scheme [in particular with the extended transition state (ETS) method, initially developed by Ziegler and Rauk], it is possible to give a quantitative (i.e., energetic) description of the σ‐donor ( E σ ) and π‐acceptor ( E π ) contributions to the metal–ligand bond. Thus, in the last years, the ETS‐NOCV approach has emerged as a very precious tool for shedding light on the nature of metal‐to‐ligand interactions, as documented in the different cases studied . In the present study, we applied ETS‐NOCV to a series of [Mo(CO) 4 (phen*)] complexes (phen* = substituted 1,10‐phenanthroline) with the purpose of describing and quantifying the σ‐donor and π‐acceptor properties of phen* depending on their substitution.…”

Bonding Analysis of TM(cAAC)2 (TM = Cu, Ag, and Au) and the Importance of Reference State

“…The neutral coinage transition metals complexes [TM­(cAAC) 2 ] (TM = Cu, Ag, and Au), which are generated by reduction of the [TM­(cAAC) 2 ] + cations for TM = Cu,Au, exhibit interesting experimental and computational metrics, linear coordination geometries, EPR g-values, and hyperfine couplings, indicating that the unpaired spin density is largely located on the carbene carbon atoms and that C-TM bond lengths that are slightly longer for the [TM­(cAAC) 2 ] + cations than for the neutral complexes. A recent analysis of the bonding in these complexes using energy decomposition analysis–natural orbitals for chemical valence (EDA-NOCV) − and natural bond orbital (NBO) methods − prompted several claims from the authors that appear contrary to the empirical data and to previously published examinations of bonding at transition metals. Representative statements include “Metal-ligand interactions in [TM­(cAAC) 2 ] involve the TM in the excited 2 P state,” “cAAC ligands in TM­(cAAC) 2 are stronger π-acceptors than σ donors!,” “The TM­(pπ) → (cAAC) 2 backdonation··· is not recognized by the calculation of the bonding orbitals by the NBO method because it is biased against mixing of n­(p) functions for the TMs,” and “The NBO picture of the C-TM-C bonding situation does not correctly represent the nature of the metal-ligand interaction in [TM­(cAAC) 2 ].”…”