Host-Guest Complexes of P,N-Containing Cyclophanes with Heteroaromatic Ammonium Salts in Solution

Zhelezina, Yulia A.; Balueva, A. S.; Ignatieva, Svetlana N.; Карасик, А. А.; Sinyashin, Оleg G.

doi:10.1080/10426507.2012.740701

Cited by 4 publications

References 3 publications

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Endo or Exo? Structures of Gas‐Phase Alkali Metal Cation/Aromatic Half‐Belt Complexes

et al. 2018

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1,1,9,9-Tetramethyl[9](2,11)teropyrenophane (TM9TP), a belt-shaped molecule, has a sizable cavity that molecules or ions could occupy. In this study, the question of whether TM9TP forms gas-phase ion-molecule complexes with metal cations (K , Rb , Cs ) situated inside or outside the TM9TP cavity was addressed using both experimental and computational methods. Complexes were trapped in a Fourier transform ion cyclotron resonance mass spectrometer and their structures were explored by some novel physical chemistry/mass spectrometry methods. Blackbody infrared radiative dissociation kinetics reveal two populations of ions, a fast dissociating fraction and a persistent fraction. Infrared multiphoton dissociation spectra (vibrational spectra) provide very strong evidence that the most abundant population is a complex where the metal cation is inside the TM9TP cavity, endo-TM9TP. Red-shifted C-H stretching bands present in the gas-phase vibrational spectra of these ionic complexes show that there is an interaction between the metal cation and bridge C-H bonds due to the cation sitting inside the cavity of TM9TP. B3LYP/6-31+G(d,p) calculations showed the endo complexes to be the lowest in energy; about 60 kJ mol more thermodynamically stable and more than 120 kJ mol kinetically more stable than the exo complex.

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