Halogen Bonding in Self-Assembling Systems: A Comparison of Intra- and Interchain Binding Energies

Publication date: Available online 10 July 2018Source: Computational and Theoretical ChemistryAuthor(s): Angelica P. Orlova, Paul G. JasienAbstractCalculations using the M06-2X and ωB97-XD density functionals with a triple-zeta quality polarized basis sets have been used to investigate the binding energies in a series of halogen bonded complexes of C2F4I2 with NC(CH2)nCN (n = 0-2). Results for complexes with monomer ratios from 1:1 to 3:3 indicate a near constant binding energies per halogen bond of ∼8 kJ/mol, ∼13 kJ/mol, and ∼14 kJ/mol for n = 0-2, respectively, indicating no observable cooperative effects in the linear halogen bonding. Results from calculations on the stacking energy of the linear chains for systems up to 3:3 indicated that these binding energies were comparable to those for the linear halogen bonds. The strong stacking interaction is hypothesized to be due to favorable electrostatic forces between the F atoms on C2F4I2 with either adjacent H atoms on NC(CH2)2CN, or the C-C π-hole on NCCN. The stacking interactions showed a significant cooperative effect, as well as a synergistic effect with the linear halogen bonds as demonstrated by a shortening of the I•••N distances in the component chains. Binding energies for all 1:1 complexes of C2F4I2 and C4F8I2 with NC(CH2)nCN (n = 0-4) show a strong linear correlation with the ΔESP between the positive σ-hole on the I atom and the negative region around the N atom lone pair.Graphical abstractIntrac...
Source: Computational and Theoretical Chemistry - Category: Chemistry Source Type: research
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