%0 Journal Article %A Wolk, Arron B. %A Garand, Etienne %A Jones, Ian M. %A Hamilton, Andrew D. %A Johnson, Mark A. %D 2013 %T Quantifying Intrinsic Ion-Driven Conformational Changes in Diphenylacetylene Supramolecular Switches with Cryogenic Ion Vibrational Spectroscopy %U https://acs.figshare.com/articles/journal_contribution/Quantifying_Intrinsic_Ion_Driven_Conformational_Changes_in_Diphenylacetylene_Supramolecular_Switches_with_Cryogenic_Ion_Vibrational_Spectroscopy/2392945 %R 10.1021/jp3111925.s001 %2 https://acs.figshare.com/ndownloader/files/4032637 %K Cryogenic Ion Vibrational SpectroscopyWe report %K chloride concentrations %K intramolecular %K transition state %K urea NH donors %K 10 K ion trap %K ion breaks %K D 2 adducts %K Na %K TMA %K Diphenylacetylene Supramolecular Switches %K DPA %K ion accommodation profile %X We report how two flexible diphenylacetylene (DPA) derivatives distort to accommodate both cationic and anionic partners in the binary X±·DPA series with X = TMA+ (tetramethylammonium), Na+, Cl, Br, and I. This is accomplished through theoretical analysis of X±·DPA·2D2 vibrational spectra, acquired by predissociation of the weakly bound D2 adducts formed in a 10 K ion trap. DPA binds the weakly coordinating TMA+ ion with an arrangement similar to that of the neutral compound, whereas the smaller Na+ 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. %I ACS Publications