Nitrate salt of a hydrocarbazole oxime cation and a hydrated co-crystal of its chloride salt with cyclohexane-1,2,3-trione 1,3-dioxime

In the presence of nickel(II) salts, cyclohexane-1,3-dione dioxime is transformed into a hydrocarbazole oxime cation, isolated as a nitrate salt, N ,9-dihydroxy-5-(hydroxyimino)-2,3,4,5,6,7,8,9-octahydro-1 H -carbazol-4-iminium nitrate ( 1 , C 12 H 16 N 3 O 3 + ·NO 3 − ), and as a hydrated chloride co-crystal with cyclohexane-1,2,3-trione 1,3-dioxime, N ,9-dihydroxy-5-(hydroxyimino)-2,3,4,5,6,7,8,9-octahydro-1 H -carbazol-4-iminium chloride–cyclohexane-1,2,3-trione 1,3-dioxime–water (1/1/3) ( 2 , C 12 H 16 N 3 O 3 + ·Cl − ·C 6 H 8 N 2 O 3 ·3H 2 O). In 1 , the cation and nitrate anion occupy mirror sites. The symmetry-related ring methylene C atoms in the cation are disordered over two positions [occupancies 0.896 (12) and 0.104 (12)]. The asymmetric unit of 2 contains one cation, one trionedioxime molecule, one chloride anion and three water molecules; one water oxygen is disordered over two sites [occupancies 0.935 (7) and 0.065 (7)]. Both cations have an intramolecular N—H...N contact, with the proton distributed over mirror-related sites in 1 but assigned to a single nitrogen site in 2 . The hydroxy group attached to the nitrogen at the 9-position of the hydrocarbazole moiety in 1 forms a hydrogen bond to the nitrate anion, whereas chloride, trionedioxime and water molecules participate in the hydrogen-bonding network of 2 .