Use of the Ni(dithiooxalate)22- unit as a molecular tecton in crystal engineering

The use of NH⋯XM (X = Cl, Br) supramolecular synthons based on anionic perhalometallate hydrogen bond acceptors and cationic, usually pyridinium, N-H donors has previously allowed controlled crystal synthesis. The use of different molecular tectons (building blocks) with new but analogous synthons to generate a more diverse range of crystal structures is described. The nickel(ii) bis(dithiooxalate) dianion (B) is shown to hydrogen bond effectively to a variety of pyridinium cations, yielding structures with motifs of planned dimensionality and form. The structural mimicry of the ]PtCl 4[2- tecton by B is described and analysed in the structures of ]4,4′-H2bipy[]Ni(S2C2O 2)2[ (1), ]HNC5H4CO 2H-4[2]Ni(S2C2O2) 2[·2H2O (2), ]HNC5H4CO 2H-3[2]Ni(S2C2O2) 2[ (3), ]H2NC5H10CO 2H-4[2]Ni(S2C2O2) 2[ (4) and ]HN(Me)C5H10CO2H-4[ 2]Ni(S2C2O2)2[ (5). The chelating dithiooxalate-HN interaction is a robust and reliable synthon even in the presence of alternative donors and acceptors. The carbonyl functions are also potent hydrogen bond acceptors in the plane of the anion. © 2002 The Royal Society of Chemistry.