Oxidation of germanium(II) azides with HN3: a convenient route to six-co-ordinate triazidogermanium(IV) compounds

Abstract

Reaction of GeCl2(C4H8O2) 1 with NaLOEt [LOEt = (C5H5)Co{P(O)(OEt)2}3] gave LOEtGeCl 2, which reacts with NaN3 to afford the germanium(II) azide LOEtGeN33. A dissociation equilibrium between 3 and the ions [LOEtGe]+ and N3− exists in solution, which is strongly dependent on the solvent polarity. Dissociation into ions is observed in solution for a variety of other four-co-ordinate germanium(II) azides bearing an anionic tridentate ligand. The crystal structures of 2 and 3 revealed a pseudo trigonal-bipyramidal co-ordination geometry around the germanium atom and an unsymmetric bonding of the LOEt ligand with one long Ge–Oax and two considerably shorter Ge–Oeq bonds. The structural data are compared with those of other four-co-ordinate germanium(II) chlorides and azides indicating the presence of a polar Ge–X bond (X = Cl or N3) in 2 and 3. Oxidation of 3 with two equivalents of HN3 gave selectively the six-co-ordinate triazidogermanium(IV) compound LOEtGe(N3)34. Similarly, oxidation of the germanium(II) azide Tp′GeN35 [Tp′ = HB(3,5-Me2pz)3, 3,5-Me2pz = 3,5-dimethylpyrazol-1-yl] with HN3 affords selectively Tp′Ge(N3)36. The crystal structures of 4 and 6 have been determined and are compared with those of other six-co-ordinate germanium(IV) polyazides.