Molecular Co-Crystals of Carboxylic Acids. 23. The 1:1 Adducts of 3-Amino-1H-1,2,4-triazole with 5-Nitrosalicylic Acid and 3,5-Dinitrosalicylic Acid

The structures of the 1:1 molecular adducts of the herbicide 3-amino-1H-1,2,4-triazole (amitrole, 3-AT) with 5-nitrosalicylic acid (5-NSA), 3-amino-2H,4H⁺-1,2,4-triazolium nitrosalicylate, C₂H₅N₄⁺.C₇H₄NO₅^-, (1), and 3,5-dinitrosalicylic acid (DNSA), 3-amino-2H,4H⁺-1,2,4-triazolium 3,5-dinitrosalicylate, C₂H₅N₄⁺.C₇H₃N₂O₇^-, (2), have been determined by X-ray diffraction and refined to residuals R = 0.035 and 0.037 for 1355 and 826 observed reflections, respectively. In both adducts, the acid protonates the hetero N atom of the amitrole ring. For (1), both molecules are involved in a network structure in which all available proton-donor and acceptor atoms, including the nitro O atoms, participate in hydrogen bonding. For (2), the two-dimensional sheet structure involves those atoms comprising the proximal sites of the interacting molecules, with limited interaction through the nitro O atoms.

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