Dinuclear Triple-Stranded Helicates from Rigid Oligo-p-phenylene Ligands: Self-Assembly and Ligand Self-Recognition

The rigid rod oligo-p-phenylene type dicatechol ligands 1-3-H4 form dinuclear triple-stranded helicates M4[(1−3)3Ti2] in the presence of appropriate counterions (M = Li, Na, K, or NH4). Studies on the self-recognition ability of the ligands show that self-recognition takes place if mixtures of ligands with significantly different sizes (1/2) are used in coordination studies, or if ligands are used which do not match for geometric reasons (1/4). Mixtures of ligands with a similar geometric preference (2/5) do not lead to self-recognition, but instead give mixtures of hetero- and homoleptic complexes. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)