Spectrometry and Gas Phase Chemistry of Supramolecules

Many researchers still consider mass spectrometry [1] to be a rather destructive method. The soft ionization methods - despite the revolution they caused in the life sciences - are often not appropriately highlighted in lecture courses on mass spectrometry, so prejudice has it that mass spectrometry almost unavoidably causes fragmentation even of covalent bonds. Consequently, the examination of noncovalent complexes is too often considered to be futile and successful only in some very special cases. However, the soft ionizaton methods developed in the 1980s reduce fragmentation to a minimum and even noncovalent, weakly-bound complexes can be ionized without complete destruction. Technically, the problem of intact ionization of weakly-bound complexes can be solved in many cases [2]. 

Consequently, a more fundamental question arises Why should one apply mass spectrometry to supramolecules What is the motivation and what is the added value of using this method together with other techniques that are maybe more commonly used in supramolecular chemistry The present chapter elaborates on the hypothesis that the potential of mass spectrometry goes far beyond the analytical characterization of complexes with respect to their exact masses, charge states, stoichiometries, or purity. In fact, the information that can be gained is complementary to other methods such as NMR spectroscopy and includes structural aspects, reactivity, and even thermochemistry. Examination of supramolecules by mass spectrometry involves their transfer into the high vacuum of the mass spectrometer and thus implies that isolated particles are investigated. There is no 

In principle, a mass spectrometer consists of two segments an ion source and a mass analyzer. Ion sources are required for the transfer of the sample from the condensed phase (i.e. from solution or the solid state) into the high vacuum as a 

---