Issue 13, 2012

Metal salts of the 4,5-dicyano-2H-1,2,3-triazole anion ([C4N5])

Abstract

Diaminomaleodinitrile was reacted at low temperatures with in situ generated nitrous acid to form 4,5-dicyano-2H-1,2,3-triazole (1) in yields above 90%. Crystalline 1 was then reacted with one equivalent of a suitable alkali or alkaline earth metal base (typically a hydroxide or a carbonate) in a polar solvent to form the corresponding alkali and alkaline earth metal salts of 4,5-dicyano-2H-1,2,3-triazole (compounds 2–9). The thermal stability of the metal salts 2–9 was assessed by differential scanning calorimetry, which showed excellent thermal stabilities up to above 350 °C. Due to the energetic character of triazole-based salts, initial safety testing was used to assess the sensitivity of compounds 2–9 towards impact, friction, electrostatic discharge and fast heating. These results revealed very low sensitivities towards all four stimuli. Additionally, compounds 2–9 were characterized by mass spectrometry, elemental analysis, infrared and Raman spectroscopy and (1H, 13C and 14N) NMR spectroscopy. We also determined the solid state structure of the 4,5-dicyano-2H-1,2,3-triazole anion of one of the alkali metal salts (4: Monoclinic, P21/c, a = 9.389(1) Å, b = 10.603(1) Å, c = 6.924(1) Å, β = 102.75(1)° and V = 1036.58(3) Å3) and one of the alkaline earth metal salts (6: Monoclinic, P21/c, a = 9.243(1) Å, b = 15.828(2) Å, c = 6.463(1) Å, β = 90.23(1)° and V = 945.5(2) Å3). Furthermore, we noted the hydrolysis of one of the cyano groups of the 4,5-dicyano-2H-1,2,3-triazole anion in the strontium salt 8 to form the 5-cyano-2H-1,2,3-triazole-4-carboxylic acid derivative 8b, as confirmed by X-ray studies (8b: Monoclinic, P21/n, a = 6.950(1) Å, b = 17.769(1) Å, c = 13.858(1) Å, β = 92.98(1)° and V = 1709.1(1) Å3). Lastly, we computed the NBO and Mülliken charges for the anion of compounds 2–9 and those of the anion of compound 8b.

Graphical abstract: Metal salts of the 4,5-dicyano-2H-1,2,3-triazole anion ([C4N5]−)

Supplementary files

Article information

Article type
Paper
Submitted
03 Nov 2011
Accepted
13 Jan 2012
First published
21 Feb 2012

Dalton Trans., 2012,41, 3817-3825

Metal salts of the 4,5-dicyano-2H-1,2,3-triazole anion ([C4N5])

C. M. Sabaté, E. Jeanneau and H. Delalu, Dalton Trans., 2012, 41, 3817 DOI: 10.1039/C2DT12100J

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