Germanium-Containing Heterobicyclic 10-π-Electron Ring Systems. Synthesis and Characterization of Neutral and Cationic Germanium(II) Derivatives of Aminotroponiminates

The neutral and cationic aminotroponiminate derivatives of germanium(II) have been investigated. The treatment of GeCl 2 ·(1,4-dioxane) with [( i -Pr) 2 ATI]Li or [(Me) 2 ATI]Li in a 1:1 molar ratio gave the corresponding monochloro germanium(II) complex. Substitution of the chloride ion of [( i -Pr) 2 ATI]GeCl with weakly coordinating anions [CF 3 SO 3 ] - and [(η 5 -C 5 H 5 )ZrCl 2 (μ-Cl) 3 ZrCl 2 (η 5 -C 5 H 5 )] - led to cationic germanium(II) species containing {[( i -Pr) 2 ATI]Ge} + ion. Although NMR data of the cationic species show notable differences relative to their neutral analog, the solid state data show only minor changes in the C 7 N 2 Ge moiety. The Ge−N bond distances of the cations are not indicative of significant Ge−N π-bonding. These compounds feature some of the smallest N−Ge−N angles known for Ge(II) compounds. Attempted synthesis of the tetraphenylborate salt of {[(Me) 2 ATI]Ge} + led to a phenyl group transfer product [(Me) 2 ATI]GePh·BPh 3 with a Ge(II)−B bond. Details of the 1 H, 13 C NMR spectroscopy and X-ray crystal structures of all these compounds are described.