Germanium-containing heterobicyclic 10-pi-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 GeCl2 .(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 [CF3SO3](-) and [(eta(5)-C-5 H-5)ZrCl2(mu-Cl)(3)ZrCl2(eta(5)-C5H5)](-) 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 C7N2Ge moiety. The Ge-N bond distances of the cations are not indicative of significant Ge-N pi-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 . BPh3 with a Ge(II)-B bond. Details of the H-1, C-13 NMR spectroscopy and X-ray crystal structures of all these compounds are described.