Amphiphile structures in the solid state : Complex cations with lipophilic substituents

Structural characterisation of hexamine cage complexes, two containing diamagnetic Co-III and one containing paramagnetic Cu-II, to which both rather short (C-4) and relatively long (C-13) alkyl substituents have been attached, shows that while the longer "tail" introduces an anticipated bilayer form to the crystalline solid, even the shorter tail can be associated with a form of aggregation of lipophilic entities in the crystal. The short tail at least may also be involved in interactions with anions of a complex type. As surfactants, functionalised edge complexes contain a head group, which is a multi-site hydrogen-bonding entity, and which can thus provide a mechanism for further aggregation concomitant with that of any apolar functionality. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)