Neutral Pentacoordinate and Hexacoordinate Germanium(IV) Complexes:  Valence Expansion At Gemanium By Transannular Bonding Of Selenium in an Eight-Membered Ring1

The neutral pentacoordinate Ge complexes 4 and 5 were prepared and characterized by crystallographic and NMR spectra analysis. The transannular Se atoms in the eight-membered rings of both 4 and 5 are bonded to Ge. The geometry at Ge is displaced 50.3% from tetrahedral to trigonal bipyramidal in 4, and 83.9% to octahedral in 5.