Aliphatic C−H/π Interactions:  Methane−Benzene, Methane−Phenol, and Methane−Indole Complexes

Abstract

Noncovalent C-H/pi interactions are prevalent in biochemistry and are important in molecular recognition. In this work, we present potential energy curves for methane-benzene, methane-phenol, and methane-indole complexes as prototypes for interactions between C-H bonds and the aromatic components of phenylalanine, tyrosine, and tryptophan. Second-order perturbation theory (MP2) is used in conjunction with the aug-cc-pVDZ and aug-cc-pVTZ basis sets to determine the counterpoise-corrected interaction energy for selected complex configurations. Using corrections for higher-order electron correlation determined with coupled-cluster theory through perturbative triples [CCSD(T)] in the aug-cc-pVDZ basis set, we estimate, through an additive approximation, results at the very accurate CCSD(T)/aug-cc-pVTZ level of theory. Symmetry-adapted perturbation theory (SAPT) is employed to determine the physically significant components of the total interaction energy for each complex.

A Systematic CCSD(T) Study of Long-Range and Noncovalent Interactions between Benzene and a Series of First- and Second-Row Hydrides and Rare Gas Atoms

“…The RVS-SCF results in Table 6 may also be compared with analogous SAPT2 results from the literature for the methane (E elst ) -1.153, E exch ) 2.164, E disp ) -2.025 kcal/mol) 24 and hydrogen sulfide complexes (E elst ) -3.18, E exch ) 4.19, E disp ) -4.16 kcal/mol). 10 Although the SAPT2 total and component energies differ from the RVS-SCF results by up to 21%, the overall breakdown profile is similar, irrespective of the method used.…”

“…2,10 In particular, Grimme has recently noted that very accurate ab initio data are still missing for complexes of benzene with small molecules. 2 Therefore, the purpose of this paper is to build on previous studies of benzene-small molecule complexes [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] to provide equilibrium binding energies (D e ) and potential energy curves with "subchemical" accuracy (i.e., accurate to within a fraction of a kcal/mol) for such systems. For systems where the zero-point energy has also been accurately determined, the vibrationally averaged binding energy (D 0 ) is calculated and compared with experimental results.…”

In the pursuit of small “red shift” of C–H stretching vibrational frequency of C–H⋯π interactions for benzene dimer: How to amend MP2 calculations to reproduce the experimental results

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] These interactions play important role in crystal packing, biomolecular recognition processes, and various aspects of materials science. 1,2 Special importance has been given to benzene dimer because it can serve as a prototype for -interactions in aromatic systems.…”

“…Recently, substituent effects on -interactions in the benzene dimer have stimulated theoretical interest. [13][14][15][16] An excellent work of Wheeler and Houk 16 has revealed that additional dispersive interactions between the substituents and the other benzene ring play crucial role in stabilizing most of the substituted benzene dimers. In our group, we have investigated theand cation-interactions of large molecular systems.…”

Accurate prediction of the energetics of weakly bound complexes using the machine learning method kriging

“…The ammonia…benzene, water…benzene, HCN…benzene and T-benzene (C 2v ) dimer complexes involve a weak hydrogen bond between the hydrogen atom of the donor non-benzene molecule interacting with the delocalised π-system of the benzene ring. The stackedbenzene (C 2h ) dimer involves a π-π stacking interaction, and the methane…benzene complex involves a C-H/π bond, common in protein side chains [31].…”