title: C-H···π interactions and the nature of the donor carbon atom.
abstract: The influence of multiple substituents (F, CH3, NO2, CN, Cl, OH and NH2) on the C-H···π interaction in benzene-ethylene complex was investigated using the estimated CCSD(T) method and complete basis set limit. The results were compared with our earlier reported complexes of benzene-acetylene and benzene-methane, thus completing the sp, sp(2) and sp(3) series of C-H donors. The stabilization energy values for multiple fluoro-substituted benzene-ethylene complexes are found to be very close to those of the multiple fluoro-substituted benzene-methane complexes. Expectedly, the stabilization energies for the multiple methyl-substituted benzene-ethylene complexes lie between those of the multiple methyl-substituted benzene-methane and benzene-acetylene complexes. Energy decomposition analysis using the DFT-SAPT method predicts the dispersion energy to be dominant, similar to the benzene-methane complexes. For the symmetrically disubstituted complexes (-OH, -Cl, -NH2, -CN and -NO2), additional C-H···X interaction was observed, possibly due to the angular orientation of the ethylene molecule. Multidimensional correlation analysis between the electrostatic, dispersion and exchange-repulsion with the C-H···π interaction distance (r), Hammett constant (σ) and the molar refractivity (MR) revealed strong correlation between dispersion energy and the C-H···π interaction distance (r) as well as molar refractivity (MR).
authors.affiliation: International Institute of Information Technology Bangalore , Bangalore 560100, Karnataka, India.
authors.forename: Brijesh Kumar
authors.initials: BK
authors.lastname: Mishra
authors.forename: Milind Madhusudan
authors.initials: MM
authors.lastname: Deshmukh
authors.forename: Ramanathan
authors.initials: R
authors.lastname: Venkatnarayan
mesh_terms: D001555:Benzene Derivatives / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008956:Models, Chemical; D011789:Quantum Theory
chemical_list: D001555:Benzene Derivatives; D005030:Ethylenes; D002244:Carbon; C036216:ethylene