Gas-phase H/D-exchange experiments in supramolecular chemistry

Abstract

This review discusses the potential of gas-phase H/D-exchange (HDX) reactions for supramolecular chemistry. The exchange of labile H against D atoms can help unravel structural details of supramolecules-in particular when combined with other gas-phase experiments, e.g. ion-mobility MS. The presence of different, non-interconverting structures in an ion population can lead to bimodal exchange distributions. Since hydrogen bonding has an effect on the exchange rates, the number and positions of hydrogen bonds can often be determined. Zwitterionic and charge-solvated structures of amino acids and peptides can be distinguished. Beyond structure, dynamic features such as the mobility of building blocks within complexes can be investigated.

Binary Zinc Azides

“…[13] Zinc azide prepared by this procedure was found to contain only negligible amountso fh ydroxideg roups or residual water,a nd was very sensitive to friction and shock, as was later confirmed by Winkler and Krischner. [12] Moreover, the latter werea ble to record powder X-ray diffraction data, which, however,d iffered considerably from the earlier data published by Yoganarasimhan and Jain (see above). [11a, 12]…”

“…[5,15] In agreement with the previous findings, both Zn(N 3 ) 2 ·2 NH 3 and Zn(N 3 ) 2 ·2.5 H 2 Or eleased the vast bulk of solventu pon thermalt reatment in vacuo at 60-130 8C, and 60-100 8C, respectively. [2,11,12] Astonishingly,t he materialo btained this way, just as the product from simple dehydration of Zn(N 3 ) 2 ·2.5 H 2 O with P 4 O 10 for several days, were almosti dentical accordingt o vibrational spectroscopy (IR/Raman). [15] However,o wing to its amorphousn ature,z inc azide prepared by these procedures was not suited for powder X-ray diffraction and alwaysc ontained traces of hydroxidei mpurities, or displayed residual NÀ Hv ibrations, respectively,a sd educed from the IR spectra (Supporting Information, Figures S21, S22).…”

“…[11] In contrast, Winkler and Krischner found that zinc azide obtained by dehydration still contained ac onsiderable amount of hydroxide and water,w hich was furthers upported by the published IR data. [12] As early as 1917, the synthesis of binary Zn(N 3 ) 2 was achieved by Wçhler and Martin in the reactiono ff reshly prepared zinc carbonate or basic zinc azide with dry,e thereal hydrazoic acid (Scheme 2). [13] Zinc azide prepared by this procedure was found to contain only negligible amountso fh ydroxideg roups or residual water,a nd was very sensitive to friction and shock, as was later confirmed by Winkler and Krischner.…”

Computational methods and challenges in hydrogen/deuterium exchange mass spectrometry

“…For more details on solution‐ and gas‐phase hydrogen exchange mechanisms, we refer to numerous excellent reviews (Englander et al, , ; Smith, Deng, & Zhang, ; Hoofnagle, Resing, & Ahn, ; Kaltashov & Eyles, ; Chalmers et al, , ,; Wales & Engen, ; Konermann, Tong, & Pan, ; Engen, ; Morgan & Engen, ; Marcsisin & Engen, ; Konermann, Pan, & Liu, ; Winkler, Dzyuba, & Schalley, ; Percy et al, ; Wales, Eggertson, & Engen, ).…”

Photooxygenation and gas‐phase reactivity of multiply threaded pseudorotaxanes

“…However, the high complexity in the supramolecular systems or structures requires more sophisticated analytical tools for their characterization. In this regard, mass spectrometry has proven to be very useful to investigate supramolecular complexes in the gas phase . Nevertheless, the transfer of supramolecular structures from solution to the gas phase would significantly alter its properties.…”