Synthesis and characterization of transition-metal-substituted germanium and tin azides: X-ray crystal structures of [{Fe(CO)2(cp)}2E(N3)2](cp =η-C5H5, E = Ge or Sn)

Abstract

Treatment of acetonitrile solutions of [{Fe(CO)₂(cp)}₂EX₂](cp =η-C₅H₅; E = Ge, X = Br; E = Sn, X = Cl) with an excess of sodium azide affords the compounds [{Fe(CO)₂(cp)}₂E(N₃)₂](E = Ge or Sn). X-Ray crystallographic analyses of these compounds show that the Group 14 atom has a distorted-tetrahedral environment, with enlarged Fe–E–Fe angles and reduced N–E–N angles. Contributions from various resonance forms of the azide ligand are discussed, based on the solid-state data, and are compared to expectations based on solid-state and solution ν_asym.(N₃) and ν(CO) i.r. stretching frequencies.