A structural hierarchy in the hydrogen-bonded adduct N,N'-dimethylpiperazine-tartaric acid-water (1/2/2): an N-component, N-dimensional structure (N = 3) with substructures having N = 1 and 2

In the hydrated adduct N,N'-dimethylpiperazine-1,4-diium bis(3-carboxy-2,3-dihydroxypropanoate) dihydrate, [MeNH(CH2CH2)(2)NHMe](2+).2(C4H5O6)(-).2H(2)O or C6H16N22+. 2C(4)H(5)O(6)(-).2H(2)O, formed between racemic tartaric acid and N,N'-dimethylpiperazine (triclinic P (1) over bar, Z' = 0.5), the cations lie across centres of inversion. The anions alone form chains, and anions and water molecules together form sheets; the sheets are linked by the cations to form a pillared-layer framework. The supramolecular architecture thus takes the form of a family of N-dimensional N-component structures having N = 1, 2 or 3.