Interaction Energy Landscapes of Aromatic Heterocycles through a Reliable yet Affordable Computational Approach

Abstract

Noncovalent interactions between homodimers of several aromatic heterocycles (pyrrole, furan, thiophene, pyridine, pyridazine, pyrimidine, and pyrazine) are investigated at the ab initio level, employing the Möller-Plesset second-order perturbation theory, coupled with small Gaussian basis sets (6-31G* and 6-31G**) with specifically tuned polarization exponents. The latter are modified using a systematic and automated procedure, the MP2 approach, based on a comparison with high level CCSD(T) calculations extrapolated to a complete basis set. The MP2 results achieved with the modified 6-31G** basis set show an excellent agreement with CCSD(T)/CBS reference energies, with a standard deviation less than 0.3 kcal/mol. Exploiting its low computational cost, the MP2 approach is then used to explore sections of the intermolecular energy of the considered homodimers, with the aim of rationalizing the results. It is found that the direct electrostatic interaction between the monomers electron clouds is at the origin of some observed features, and in many cases multipoles higher than dipole play a relevant role, although often the interplay with other contributions to the noncovalent forces (as for instance induction, π-π or XH-π interactions) makes a simple rationalization rather difficult.

Density Functional Study on the Adsorption of 5-Membered N-Heterocycles on B/N/BN-Doped Graphene: Coronene as a Model System

“…Moreover, the second-order Møller–Plesset (MP2) perturbation theory is computationally less expensive (compared with CCSD(T)), but its accuracy is reported to be dependent on the type of basis set used. 39 Hobza et al suggested the use of the MP2/cc-pVTZ level of theory for this purpose, which would also be prohibitively expensive for the considered systems. 40 DFT methods are computationally more convenient than CCSD(T) and MP2 calculations and hence, in this study, DFT functionals are used.…”

“…Jacobs et al have also suggested the importance of a suitable DFT functional and basis set for estimating the noncovalent interactions. 39…”

Nonclassical B‐Hb⋯π interaction in diborane⋯localized‐π sandwiches: A DFT‐D3 study

“…Quantum chemical methods are popularly used to understand different aspects of noncovalent interactions. CCSD(T) (coupled cluster theory with perturbative triples) and MP2 (second order Moller‐Plesset) approaches are generally used for accurate estimation of weaker interactions . CCSD(T) calculation in association with complete basis set limit (CBS) is known to be gold standard in quantum chemistry .…”

DFT Study on the Formation of Homo and Hetero dimers of BN‐doped Tetracyclic fused Aromatics via π⋯π Stacking

“…Since, DFT methods are computationally more convenient than CCSD(T), therefore DFT functionals are used for the purpose. However, appropriate selection of functional (dispersion corrected) and basis set is important for accurate estimation of π⋯π stacking interactions . To find a suitable combination, two of the most common DFT functional viz.…”

“…Generally, non‐covalent interaction arises from simultaneous contribution from different forces like electrostatic, exchange, induction, dispersion etc. However, nature of π⋯π stacking between two arene systems is documented to be primarily dispersive ,,. Apart from this, reports are also there which in favour of electrostatic interaction .…”