Acta Chimica Slovaca (ACS) publishes papers on fundamental and applied aspects of chemistry, biochemistry, chemical technology, chemical engineering and process control, biotechnology and food technology. Welcome are also topics which include chemical aspects of materials, physical chemistry and chemical physics, analytical chemistry, macromolecular chemistry and biomedical engineering.

Theoretical study of substituent effects on the geometry and strain enthalpy in [2,2]paracyclophanes

Martin Michalík *, Peter Poliak, Vladimír Lukeš

Department of Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, Bratislava, SK-81237 Slovakia

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Abstract: The substituent effect on the geometry and strain enthalpy of [2,2]paracyclophane is theoretically investigated by density functional theory. Gas-phase calculations were performed for twenty distinct electron donating and electron withdrawing substituents. The largest out-of-plane distortion of phenyl rings is exhibited by —SCN and —CFgroups. On the other hand, —OH, —CHand —F groups show the minimal deformation. The strain enthalpy for unsubstituted [2,2]paracyclophane associated with repulsive forces between phenyl units reached up to 118.5 kJ mol–1. Any substitution causes increase of the strain enthalpy value proportionally to the absolute values of Hammett para-substituent constants. Two separate linear dependences with similar slopes were obtained for monosubstituted as well as double symmetrically substituted derivatives.

Keywords: Paracyclophane, B3LYP-D3 study, intermolecular forces, aromaticity, strain enthalpy, Hammett constants

Full paper in Portable Document Format: acs_0233.pdf

Acta Chimica Slovaca, Vol. 9, No. 1, 2016, pp. 6—13, DOI: 10.1515/acs-2016-0002