Exploring the Limits of Intramolecular London Dispersion Stabilization with Bulky Dispersion Energy Donors in Alkane Solution
Jan M. Schümann, Lukas Ochmann, Jonathan Becker, Ahmet Altun, Ingolf Harden, Giovanni Bistoni, Peter R. Schreiner
Abstract
We present an experimental study of a cyclooctatetraene-based molecular balance disubstituted with increasingly bulky tert -butyl ( t Bu), adamantyl (Ad), and diamantyl (Dia) substituents in the 1,4-/1,6-positions for which we determined the valence-bond shift equilibrium in n -hexane (hex), n -octane (oct), and n -dodecane (dod). Computations including implicit and explicit solvation support our temperature-dependent NMR equilibrium measurements indicating that the more sterically crowded 1,6-isomer is always favored, irrespective of solvent, and that the free energy is quite insensitive to substituent size.
Topics & Concepts
ChemistryDodecaneSteric effectsSolvationIntramolecular forceAlkaneDecaneSubstituentValence (chemistry)OctaneLondon dispersion forceHexaneCyclooctatetraeneComputational chemistrySolventDispersion (optics)PhotochemistryHydrocarbonStereochemistryOrganic chemistryMoleculevan der Waals forceOpticsPhysicsAdvanced Chemical Physics StudiesAdvanced NMR Techniques and ApplicationsSynthesis and Properties of Aromatic Compounds