Does the molecular structure of CaH2 affect the dihydrogen bonding in CaH2 … HY (Y = CH3, C2H3, C2H, CN, and NC) complexes? A quantum chemistry study using MP2 and B3LYP methods

Abstract

Second-order Møller-Plesset (MP2) and density functional theory (DFT) calculations have been carried out in order to investigate the structures and properties of dihydrogen-bonded CaH 2 HY (Y = CH 3 , C 2 H 3 , C 2 H, CN, and NC) complexes. Our calculations revealed two possible structures for CaH 2 in CaH 2 HY complexes: linear (I) and bent (II). The bond lengths, interaction energies, and strengths for HH interactions obtained by both MP2 and B3LYP methods are quite close to each other. It was found that the interaction energy decreases with increasing electron density at the Ca-H bond critical point. Atom-in-molecule (AIM) results show that for all of Ca-HH-Y interactions considered here, the Laplacian of the electron density at the HH bond critical point is positive, indicating the electrostatic nature of these Ca-HH-Y dihydrogen bonded systems. dihydrogen bond, interaction energy, NBO, AIM theory, bond critical point

Regulating effect of the halogen atoms on the cofacial dinuclear Schiff base complexes: Synthesis, spectroscopy, electrochemistry, and DFT calculations

“…Since M062X can effectively describe weak interactions, all structural optimizations were carried out at the M062X level without imposing any symmetry restraints. [40][41][42] DFT-D3 method based on the standard 6-311+ G(d, p) basis set was used to explore the relationship between molecular orbitals and reactivity. 43 Frequency calculations were carried out at the same level of theory to validate the stability of all structures.…”

“…The computational methodology in this study consists of two consecutive steps. Since M062X can effectively describe weak interactions, all structural optimizations were carried out at the M062X level without imposing any symmetry restraints 40–42 . DFT–D3 method based on the standard 6‐311+ G(d, p) basis set was used to explore the relationship between molecular orbitals and reactivity 43 .…”

Assessing Parameter Suitability for the Strength Evaluation of Intramolecular Resonance Assisted Hydrogen Bonding in o-Carbonyl Hydroquinones

“…However, current computational chemistry allows one to assess, theoretically, the strength of IMBH through parameters such as the distance hydrogen-acceptor, the distance donor-acceptor, and the hydrogen bond angle [9]. Among the theoretical estimated parameters for the HB interaction, those from Natural Bond Orbital (NBO) and Quantum Theory of Atoms in Molecules (QTAIM) analysis [9,10,11,12,13] are the most popular. In this field, DFT methodologies have proven to be valuable tools to calculate molecular properties with an appreciably low computational time demand compared with ab initio methodologies.…”