Cation-π interactions are one of the most important classes of noncovalent bonding, and are seen throughout biology, chemistry, and materials science. However, in almost every documented case, these interactions play only a supporting role to much stronger covalent or dative bonds, thus making examples of exclusive cation-π bonding exceedingly rare. In this study, a neutral diboryne molecule is found to encapsulate the light alkali metal cations Li(+) and Na(+) in the absence of a net charge, covalent bonds, or lone-pair donor groups. The resulting encapsulation complexes are, to our knowledge, the first structurally authenticated species in which a neutral molecule binds the light alkali metals exclusively through cation-π interactions.
Keywords: alkali metals; boron; cation-π interactions; lithium; sodium.
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.