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) x 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'-py2NH)2(cdm)2] x 2 MeOH, [Ni(cyclam)(cdm)2], and [Cu(cyclam)(cdm)2] x 2 MeOH (cyclam = 1,4,8,11-tetraazacyclotetradecane, 2,2'-py2NH = 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.
Turner
David R
DR
School of Chemistry, Monash University, Clayton, Vic 3800, Australia.
Pek
Sze Nee
SN
Batten
Stuart R
SR