Quantifying Intrinsic Ion-Driven Conformational Changes in Diphenylacetylene Supramolecular Switches with Cryogenic Ion Vibrational Spectroscopy Arron B. Wolk Etienne Garand Ian M. Jones Andrew D. Hamilton Mark A. Johnson 10.1021/jp3111925.s001 https://acs.figshare.com/articles/journal_contribution/Quantifying_Intrinsic_Ion_Driven_Conformational_Changes_in_Diphenylacetylene_Supramolecular_Switches_with_Cryogenic_Ion_Vibrational_Spectroscopy/2392945 We report how two flexible diphenylacetylene (DPA) derivatives distort to accommodate both cationic and anionic partners in the binary X<sup>±</sup>·DPA series with X = TMA<sup>+</sup> (tetramethylammonium), Na<sup>+</sup>, Cl<sup>–</sup>, Br<sup>–</sup>, and I<sup>–</sup>. This is accomplished through theoretical analysis of X<sup>±</sup>·DPA·2D<sub>2</sub> vibrational spectra, acquired by predissociation of the weakly bound D<sub>2</sub> adducts formed in a 10 K ion trap. DPA binds the weakly coordinating TMA<sup>+</sup> ion with an arrangement similar to that of the neutral compound, whereas the smaller Na<sup>+</sup> ion breaks all intramolecular H-bonds yielding a structure akin to the transition state for interconversion of the two conformations in neutral DPA. Halides coordinate to the urea NH donors in a bidentate H-bonded configuration analogous to the single intramolecular H-bonded motif identified at high chloride concentrations in solution. Three positions of the “switch” are thus identified in the intrinsic ion accommodation profile that differ by the number of intramolecular H-bonds (0, 1, or 2) at play. 2013-07-25 00:00:00 Cryogenic Ion Vibrational SpectroscopyWe report chloride concentrations intramolecular transition state urea NH donors 10 K ion trap ion breaks D 2 adducts Na TMA Diphenylacetylene Supramolecular Switches DPA ion accommodation profile