Structure of an oxo-bridged germatrane dimer

The reaction of tris(2-hydroxyphenyl)amine with Ge(OEt)(4) produced 1,1'-oxybis(1-germa-5-aza-2,8,9-trioxatribenzobicycloclo[3.3.3]undeca-3,6,10-triene) (11). This reaction proceeded via 1-ethoxy-1-germa-5-aza-2,8,9-trioxatribenzobicyclo[3.3.3]undeca-3,6,10-triene (10a). In ore-bridged germatrane dimer Il, the Ge-O-Ge moiety is bent at an angle of 131.2(4)degrees, and Ge-O-bridge distances are 1.750(7) and 1.743(6) Angstrom. The other Ge-O distances, by comparison, averaged 1.785(7) Angstrom. The germanium centers in 11 are nearly trigonal bipyramidal by virtue of significant interaction with transannular nitrogen: the Ge-N distances are 2.235(8) and 2.247(7) Angstrom. Ab initio calculations an 11 and H3Ge-O-GeH3 predict a Linear Ge-O-Ge geometry when d-orbitals are omitted from the basis set, but correctly predict a bent geometry when d-orbitals are used. (C) 2001 Elsevier Science B.V. All rights reserved.