Synthesis and characterization of the mixed-ligand coordination polymer Cu3Cl(N4C-NO2)2

Abstract

Reduction of copper(II) chloride using sodium ascorbate in the presence of pure sodium 5-nitro-tetrazolate (NaNT) forms copper(I) 5-nitrotetrazolate – a known initiatory explosive (DBX-1) – and the novel mixed-ligand copper(I) chloride 5-nitrotetrazolate coordination polymer Cu₃Cl(N₄C-NO₂)₂, as well as mixtures of both. The reaction is controlled by the presence of seed crystals and transition metal compounds other than CuCl₂. Cu₃Cl(N₄C-NO₂)₂ is obtained as a wine-red, air stable, water-insoluble, crystalline and highly sensitive explosive material with a greater crystal density, lower thermal stability and a higher sensitivity toward hydrolysis and shock than DBX-1. Efforts to obtain the stable and pure starting material are improved by crystallisation of NaNT as a tetrahydrate. Cu₃Cl(N₄C-NO₂)₂ and Na(H₂O)₄(NT) were characterised by single crystal and powder XRD, IR spectroscopy, magnetic and thermal measaurements, elemental analysis, particle size measurements, mass spectrometry, and by drop weight testing.