کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1194170 1492341 2009 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Infrared spectroscopy of gas-phase hydrated K+:18-crown-6 complexes: Evidence for high energy conformer trapping using the argon tagging method
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
Infrared spectroscopy of gas-phase hydrated K+:18-crown-6 complexes: Evidence for high energy conformer trapping using the argon tagging method
چکیده انگلیسی

We report our findings on the K+(18-crown-6 ether)(H2O)1Ar1–4 system using gas-phase infrared predissociation (IRPD) spectroscopy. With the argon tagging technique, we have been able to observe two different conformers, including a conformer that features a bidentate H2O actively competing with K+ for the preferred binding site inside the 18-crown-6 cavity. The detection of this conformer in our experiment was surprising since density functional theory (DFT) calculations predict it to be 55.6 kJ mol−1 higher in energy than the lower energy, traditional (K+ bound)-type conformer. We have been able to selectively probe each conformer by varying both the loss channel monitored and the number of solvating argons. The bidentate conformer was present in the IRPD spectra only when monitoring the action spectrum leading to the loss of all ligands. This suggests that the bidentate conformer undergoes rearrangement following photoexcitation to the much more stable bare K+(18-crown-6) complex. We explored the barrier to such rearrangement using D2O substitution in the experiment and with DFT calculations.

Argon tagging allows for the trapping of a high energy conformer which undergoes rearrangement upon photoexcitation by an IR photon.Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Mass Spectrometry - Volume 283, Issues 1–3, 1 June 2009, Pages 135–139
نویسندگان
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