Conformational Regulation of Multivalent Terpyridine Ligands for Self-Assembly of Heteroleptic Metallo-Supramolecules

• Published in: Journal of the American Chemical Society 2020-09, Vol.142 (39), p.16661-16667
• Main Authors: Wang, Shi-Cheng, Cheng, Kai-Yu, Fu, Jun-Hao, Cheng, Yuan-Chung, Chan, Yi-Tsu
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.0c06618

A two-ligand system composed of the predesigned multivalent and complementary terpyridine-based ligands was exploited to construct heteroleptic metallo-supramolecules and to investigate the self-assembly mechanism. Molecular stellation of the trimeric hexagon [Cd6 L 2 3] gave rise to the exclusive self-assembly of the star hexagon [Cd18 L 1 6 L 3 3] through complementary ligand pairing between the ditopic and octatopic tectons. To understand how the intermolecular heteroleptic complexation influenced the self-assembly pathway, the star hexagon was truncated into two triangular fragments: [Cd12 L 1 3 L 4 3] and [Cd12 L 1 3 L 5 3]. In the self-assembly of [Cd12 L 1 3 L 4 3], the conformational movements of hexatopic ligand L 4 could be regulated by L 1 to promote the subsequent coordination event, which was the key step to the successful multicomponent self-assembly. In contrast, the formation of [Cd12 L 1 3 L 5 3] was hampered by the geometrically mismatched intermediates.