Heterotapes: A persistent, dual-synthon hydrogen-bonding motif

The small dinitrile anion carbamoyldicyanomethanide, [C(CN)(2)(CONH2)](-) (cdm), reproducibly forms a hydrogen-bonded tape containing two different supramolecular synthons: a "heterotape". The tape incorporates both an amide dimer and a nitrile-containing ring. The robustness of the motif is confirmed by its persistence from an isolated tape in a separated ion-pair structure, [K(15c5)(2)](cdm). H2O, to its incorporation into coordination complexes of octahedral metals, thus facilitating the formation of 2D sheets. Complexes containing coligands that occupy the equatorial coordination sites, [Cu(2,2'-py(2)NH)(2)(cdm)(2)]center dot 2MeOH, [Ni(cyclam)(cdm)(2)], and [Cu(cyclam)(cdm)(2)]-2MeOH (cyclam = 1,4,8,11-tetraazacyclotetradecane, 2,2'-py(2)NH=di(2-pyridyl)amine), show retention of the heterotape motif, whilst the ethylene diamine complex [Cu(en)(2)(cdm)(2)] (en=ethylene diamine) displays an alternative hydrogen-bonding motif due to interference from the diamine ligands.