jp062740l_si_001.txt (14.72 kB)

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

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posted on 21.09.2006, 00:00 by Ashley L. Ringer, Michelle S. Figgs, Mutasem O. Sinnokrot, C. David Sherrill
Noncovalent C−H/π 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.