Gas-phase chemistry of molecular containers

The remarkable technical advances in mass spectrometry during the last decades, including soft ionisation techniques, the coupling of electrospray ionisation to flow reactors, and the broad scope of tandem mass spectrometric experiments applicable to mass-selected ions allow investigating the chemistry of molecular capsules in solution as well as in the absence of any environment. With these methods, mass spectrometry is capable of answering many questions starting from providing analytical characterisation data (elemental composition, stoichiometry, etc.) to structural aspects (connectivities, positions of building blocks in supramolecular complexes) and to the examination of solution and gas-phase reactivity including reactions inside molecular containers. The present article reviews this work with a focus rather on the chemical questions that can be answered than on the technical specialities of (tandem) mass spectrometry

Synthesis and Characterization of Stable Phosphorus Carbabetaines

Phosphorus 1,3- and 1,4-carbabetaines with ′P(+)−C−C(−)′ and ′P(+)−C−C−C(−)′ structures, respectively, in which the carbanion moiety was significantly stabilized by two trifluoromethylsulfonyl groups, have been synthesized and characterized. Analysis of their X-ray crystal structures revealed that any attractive interactions between the anionic and cationic moieties were negligibly weak. This result was corroborated by using natural bond orbital (NBO) and Bader′s quantum theory of atoms in molecules (QTAIM) models. In contrast, performing the same analysis of a known 1,3-carbabetaine equivalent, which can be drawn as a ′P(+)−C−C=C−O(−)′ resonance structure, revealed pronounced charge-transfer interactions between the anionic and cationic moieties.This work was supported by a Grant-in-Aid for Scientific Research (C) from the Japan Society for the Promotion of Science (JSPS; 17K08224), the Hoansha Foundation, and the Spanish Ministry of Economy and Competitiveness (MINECO; CTQ2015- 65060-C2-1-P, CTQ2015-65060-C2-2-P, and a Predoctoral Contract for PhD Students to C.L.-M.). We thank Professor Simon Grabowsky (Universit-t Bremen) for his helpful discussions.Peer Reviewe