Bis(melaminium) tartrate dihydrate

Abstract

In the title compound, 2C3H7N6 +·C4H4O6 2−·2H2O, in which the complete anion is generated by crystallographic twofold symmetry, there are O—H⋯O, N—H⋯O and N—H⋯N hydrogen-bonding inter­actions between neighbouring moieties, forming layers parallel to the bc plane. In addition, π–π contacts [centroid–centroid distance = 3.6541 (9) Å] between the six-membered rings of the melamine cations are observed.

Bis(2,9-dimethyl-1,10-phenanthrolin-1-ium) hydrogen (S,S)-tartrate nonahydrate

“…An interesting feature of this structure was the existence of a short hydrogen bond between adjacent tartrate anions. There are many other proton transfer structures of tartaric acid, for example, (Paixão et al, 1999;Ryttersgaard & Larsen, 2003;Bai et al, 2005;Zhang et al, 2006;Smith, et al, 2006;Suresh et al, 2006;Wang et al, 2008;Su et al, 2009), some of which feature similar short hydrogen bonds. The title structure contains two protonated cations of 2,9-dimethyl-1,10-phenanthroline (neocuproine), two anions of mono-deprotonated D-tartaric acid and nine water molecules.…”

1,10-Phenanthrolin-1-ium hydrogen (S,S)-tartrate trihydrate and a correction

“…It is added to other foods to give a sour taste, and is used as an antioxidant. Many proton transfer compounds of tartaric acid and various bases have been reported, for example, (Paixão et al, 1999;Bai et al, 2005;Zhang et al, 2006;Suresh et al, 2006;Wang et al, 2008;Su et al, 2009). The title structure contains a cation of protonated 1,10-phenanthroline, an anion of mono-deprotonated D-tartaric acid, and three water molecules ( Fig.…”

“…For related proton-transfer hydrogen tartrate structures, see: Bai et al (2005); Paixã o et al (1999); Smith et al (2006); Su et al (2009); Suresh et al (2006); Wang et al (2006Wang et al ( , 2008; Zhang et al (2006).…”