Issue 8, 2014

Explosive Werner-type cobalt(iii) complexes


A series of potentially explosive Werner-type cobalt(III) complexes comprising the anions azotetrazolate, nitrotetrazolate, picrate and dipicrylamide were prepared via simple metathetical routes. Treatment of [Co(NH3)5NO2]Cl2, trans-[Co(NH3)4(py)NO2]Cl2 (py = pyridine), trans-[Co(NH3)4(NO2)2]Cl, and [Co(NH3)5N3]Cl2 with equimolar amounts of disodium azotetrazolate, (Na2C2N10·5H2O, 1), in aqueous solutions afforded new cobalt(III) azotetrazolate salts [Co(NH3)5NO2](C2N10)·2H2O (2), trans-[Co(NH3)4(py)NO2](C2N10)·2H2O (3), trans-[Co(NH3)4(NO2)2]2(C2N10) (4), and [Co(NH3)5N3](C2N10)·H2O (5) in moderate to excellent yields (46–88%). Similar treatment of trans-[Co(NH3)4(NO2)2]Cl with 1 equiv. of sodium 5-nitrotetrazolate dihydrate (= NaNT, 6) afforded the novel cobalt(III) 5-nitrotetrazolate derivative trans-[Co(NH3)4(NO2)2](NT)·H2O (7) as orange, rectangular prismatic crystals in 64% yield. Two complex cobalt(III) picrates, trans-[Co(NH3)4(NO2)2](picrate)·H2O (9) and [Co(NH3)5N3](picrate)2 (10), were prepared in a similar manner from the corresponding chloride precursors and equimolar amounts of sodium picrate. The reaction of trans-[Co(NH3)4(NO2)2]Cl with sodium dipicrylamide (= NaDPA) in a 1 : 1 molar ratio gave the first cobalt(III) dipicrylamide, trans-[Co(NH3)4(NO2)2](DPA)·H2O (12). Finally, the highly explosive, dark blue-green dichroitic non-electrolyte complex mer-[Co(en)(py)(N3)3] (13) was formed upon treatment of [Co(en)(py)2(NH3)Cl]Cl2·H2O with excess NaN3 in hot water (93% yield). The molecular and crystal structures of 2, 3, 4, 5, 7, 9, 10, 12, and 13 were determined by single-crystal X-ray diffraction. In the solid state, all compounds comprised extensive hydrogen-bonded supramolecular networks. Representative studies of the energetic properties (impact and friction sensitivity, combustion) revealed that some of the new compounds can be classified as primary explosives.

Graphical abstract: Explosive Werner-type cobalt(iii) complexes

Supplementary files

Article information

Article type
Research Article
11 Jul 2014
30 Jul 2014
First published
06 Aug 2014
This article is Open Access
Creative Commons BY license

Inorg. Chem. Front., 2014,1, 621-640

Author version available

Explosive Werner-type cobalt(III) complexes

R. Deblitz, C. G. Hrib, S. Blaurock, P. G. Jones, G. Plenikowski and F. T. Edelmann, Inorg. Chem. Front., 2014, 1, 621 DOI: 10.1039/C4QI00094C

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity