THE CRYSTAL-STRUCTURES OF (LI3(12-CROWN-4)2[HC(CN)2]3), (NA(15-CROWN-5)[HC(CN)2]), AND (NA[N(NBU)4][HC(CN)2]2. THF)

The preparation and the crystal structures of the title compounds 1-3 are described. 1 forms a polymeric chain structure, in which one of the lithium ions is linked by Li...NCC(H)CN... bridges. The remaining lithium ions form (12-crown-4)Li[NCC(H)CN] units, which are coordinated by one of the nitrogen atoms of the dicyanomethanide ions with the lithium ions of the chain. 2 forms an ion pair, in which the sodium ion is coordinated by the five oxygen atoms of the crown ether molecule and by one nitrogen atom of the dicyanomethanide ion, 3 has a threedimensional network, in which the sodium ions are coordinated in a distorted tetrahedral manner by the nitrogen atoms of the dicyanomethanide ions. In the cavities of the network the tetrabutylammonium ions and the THF molecules are found.