Synthesis, structure, and thermal properties of soluble hydrazinium germanium(IV) and tin(IV) selenide salts

Abstract

The crystal structures of two hydrazinium-based germanium(IV) and tin(IV) selenide salts are determined. (N 2H 5) 4-Ge 2Se 6 (1) [l4 1 cd, a = 12.708(1) Å, c = 21.955(2) Å, Z = 8] and (N 2H 4) 3(N 2H 5) 4Sn 2Se 6 (2) [P1, a = 6.6475(6) Å, b = 9.5474(9) Å, c = 9.8830(10) Å, α = 94.110(2)°, β= 99.429(2)°, γ = 104.141(2)°, Z= 1] each consist of anionic dimers of edge-sharing metal selenide tetrahedra, M 2Se 64- (M = Ge or Sn), separated by hydrazinium cations and, for 2, additional neutral hydrazine molecules. Substantial hydrogen bonding exists among the hydrazine/hydrazinium molecules as well as between the hydrazinium cations and the selenide anions. Whereas the previously reported tin(IV) sulfide system, (N 2H 5) 4Sn 2S 6, decomposes cleanly to microcrystalline SnS 2 when heated to 200°C in an inert atmosphere, higher temperatures (>300°C) are required to dissociate selenium from 1 and 2 for the analogous preparations of single-phase metal selenides. The metal chalcogenide salts are highly soluble in hydrazine, as well as in a variety of amines and DMSO, highlighting the potential usefulness of these compounds as precursors for the solution deposition of the corresponding metal chalcogenide films. © 2005 American Chemical Society.