The X40×10 Halogen Bonding Benchmark Revisited: Surprising Importance of (n–1)d Subvalence Correlation

Abstract

We have re-evaluated the X40×10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)-MP2 "high-level corrections" (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies and turns out to be more important for noncovalent interactions than is generally realized; (n-1)sp subvalence correlation is much less important. The (n-1)d subvalence term is dominated by core-valence correlation; with the smaller cc-pVDZ-F12-PP and cc-pVTZ-F12-PP basis sets, basis set convergence for the core-core contribution becomes sufficiently erratic that it may compromise results overall. The two factors conspire to generate discrepancies of up to 0.9 kcal/mol (0.16 kcal/mol RMS) between the original X40×10 data and the present revision.

Minimally Empirical Double Hybrid Functionals Trained Against the GMTKN55 Database: revDSD-PBEP86-D4, revDOD-PBE-D4, and DOD-SCAN-D4

“…As seen in Table 1, about 0.1 kcal/mol can be gained in WTMAD2: in-depth analysis (Table ESI- 14) reveals that this improvement is primarily confined to the subsets BSR36 (bond separation reactions), HAL59 (halogen bonding), and HEAVY28 (heavy p-block compounds). The importance of subvalence correlation for halogen-bonded species has been shown previously 63 for the X40x10 dataset. 60 The popular simple hybrids B3LYP-D3BJ and PBE0-D3BJ are nearly tied at WTMAD2=6.5 kcal/mol.…”

Application of Halogen Bonding to Organocatalysis: A Theoretical Perspective

“…Unfortunately, it is expensive and not practical for normal application studies. Thus, it is mainly used for benchmarking purposes for small halogen-bonded systems [36][37][38][39]. Density functional theory (DFT) methods are popular alternatives because they provide sufficient accuracy with significantly lower computational expense.…”

“…Based on an extensive comparison of wave function and DFT methods on geometries and dissociation energies of halogen-bonded systems, Kozuch and Martin concluded that functionals with high exact exchange or long-range corrections, e.g., M06-2X [40], ωB97XD [41], and double hybrids, are suitable [36]. As the M06-2X functional and other latest versions of Minnesota functionals, e.g., MN15 [42], are well parametrized for noncovalent interactions and kinetics [36][37][38], M06-2X is a popular choice for studying XB organocatalysis [43]. For liquid-phase studies, the SMD universal solvation model [44] is a popular method to study the implicit solvation effect.…”

2019-nCoV vs. SARS-CoV: Which Truly Has a Higher ACE2 Affinity? A Quantum Chemical Perspective on Virus-Receptor Noncovalent Interactions

“…In this context, electronic structure methods constitute a precious (and almost exclusive) source of information on biochemically-relevant noncovalent interactions between individual molecules -which, in turn, often used for the parametrization and calibration of more approximate computational modeling techniques (such as classical molecular mechanics force fields). [7][8][9][10][11] Having been involved in a few recent quantum chemical investigations of noncovalent complexes, [12][13][14][15][16] we shall now attempt to employ B3LYP/TZVP calculationswhich have been shown to be capable of providing reliable noncovalent interaction energetics 17 -for the purpose of calculating energy differences associated with the aforementioned substitutions. In such manner, reliable energetic "gains/losses" which result from these particular substitutions may be quantitatively assessed, so that important practical conclusions regarding the above prediction may be drawn.…”