Journal of the American Chemical Society, Vol.131, No.8, 2802-2802, 2009
Synthesis and Isolation of [Fe@Ge-10](3-): A Pentagonal Prismatic Zintl Ion Cage Encapsulating an Interstitial Iron Atom
Reaction of an ethylenediamine (en) solution of the Zintl phase precursor K4Ge9 with FeAr2 (Ar = 2,6-Mes(2)C(6)H(3)) in the presence of 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) yielded the endohedral Zintl ion [Fe@Ge-10](3-) (1) which was crystallographically characterized as a [K(2,2,2-crypt)](+) salt in [K(2,2,2-crypt)](3)[Fe@Ge-10]center dot 2en. This unprecedented Zintl ion exhibits a pentagonal prismatic 10-atom germanium cage with an interstitial iron atom in the central cavity. Confirmation of the existence of the cluster anion in solution was corroborated by positive and negative ion mode electrospray mass spectrometry.