Estimating the binding ability of onium ions with CO₂and π systems: a computational investigation

Abstract

Density functional theory (DFT) calculations have been employed on 165 complexes of onium ions (NH4(+), PH4(+), OH3(+), SH3(+)) and methylated onium ions with CO2, aromatic (C6H6) and heteroaromatic (C5H5X, X = N, P; C4H5Y, Y = N, P; C4H4Z, Z = O, S) systems. The stability of CO2···onium, CO2···π and onium···π complexes was shown to be mediated through various noncovalent interactions such as hydrogen bonding, NH-π, PH-π, OH-π, SH-π, CH-π and π-π. We have discussed 17 complexes wherein the proton transfer occurs between the onium ion and the heteroaromatic system. The binding energy is found to decrease with increasing methyl substitution of the complexes containing onium ions. Binding energy components of all the noncovalent complexes were explored using localized molecular orbital energy decomposition analysis (LMO-EDA). The CO2···π complexes were primarily stabilized by the dispersion term followed by contributions from electrostatic and polarization components. In general, for onium ion complexes with CO2 or π systems, the electrostatic and polarization terms primarily contribute to stabilize the complex. As the number of methyl groups increases on the onium ion, the dispersion term is seen to have a key role in the stabilization of the complex. Quantum theory of atoms in molecules (QTAIM) analysis and charges based on natural population analysis (NPA) in various complexes have also been reported in order to determine the nature of noncovalent interactions in different complexes.

On Silylated Oxonium and Sulfonium Ions and Their Interaction with Weakly Coordinating Borate Anions

“…Similar structural features are found for the sulfur species, however,t he bending out of the Si 2 O 2 ring plane of the terminal Tg roups is much strongerp ronounced ( 59.68). [49,66,[72][73][74][87][88][89][90][91][92] Ion-pairs:A sd iscussed before, ion-pair formation stabilizes all silyliumi ons mentioned here. The difference in the SiÀEb ond lengths within the ring compared to the terminal distances is beste x-plained by as trong hyperconjugative effecto ft he lone pairs localized at both tricoordinated chalcogen atoms in a p-type atomic orbital as indicated by NBO investigations.…”

Buckybowls as adsorbents forCO2, CH4, and C2H2: Binding and structural insights from computational study

“…The derived parameters and can also indicate the type of interaction between the small molecules and π systems. Apart from ∇ 2 ρ ( r ), a positive value of is also indicative of noncovalent interaction . Also, if the ratio between − G ( r ) and V ( r ) is >1, then the interaction can be classified as noncovalent …”

“…Apart from ∇ 2 ρ ( r ), a positive value of is also indicative of noncovalent interaction . Also, if the ratio between − G ( r ) and V ( r ) is >1, then the interaction can be classified as noncovalent …”

“…The balance between those two values [ G ( r ) and V ( r )] determines the kind of interaction operating between the systems . Thus, we can assume that if the ratio, − G / V is greater than one then the nature of the interaction can be classified as noncovalent …”

“…The calculated q(r) and r 2 q(r) at the BCPs including G(r), V(r), and local electron energy density [H(r)] are used to summarize the nature of the bonding interaction. [59,60] There is a relation between these energetic characteristics, [61,62] which has been shown in eq. (3).…”