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

Abstract

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.

Self-sorting assembly of artificial building blocks

“…110 By further complicating the structure of the ligands, a variety of integrative social self-sorting patterns were easily fabricated. Chan et al reported a series of terpyridine based multi-armed ligands that assembled with Cd 2+ into nanocapsules, 111 starlike structures, 28 triangles or hexagons. 111 Other structures like snowflake 112 and cage 83,113 were also achieved by varying the structure of ligands.…”

Reaction Monitoring and Structural Characterisation of Coordination Driven Self-Assembled Systems by Ion Mobility-Mass Spectrometry

“…Recently IMS-MS has not only characterized occluded CDSA products, such as constitutional isomers and configurational isomers ( Ujma et al, 2012 ; Schultz et al, 2013 ; Liang et al, 2015 ), but also the “erroneous” intermediates formed in multicomponent systems ( Wang et al, 2020c ), or impressively, the lack thereof in a multicomponent system, due to successful pre-organization ( Wang et al, 2020a ), and even the formation of pre-organized “sequenced” CDSA systems ( Song et al, 2018 ). As such, the structural analysis of CDSA systems using IMS-MS ultimately leads us beyond characterisation of the product and side products, and towards an understanding of CDSA mechanisms.…”

“…Self-sorting is an intrinsically difficult behaviour to interrogate, more so than self-assembly alone, because all the potential supramolecular assemblies will be formed from the same source molecules, leading to similar sets of signals. IMS-MS is again uniquely situated to differentiate between self-sorted complexes that may otherwise appear similar by other techniques ( Liang et al, 2015 ; Wang et al, 2020c ). For example, TIMS-MS succeeded in differentiating between heteroleptic cages where DOSY NMR could not, however these cages were statistical products, not self-sorted ( Ebbert et al, 2019 ).…”

From Mechanically Interlocked Structures to Host–Guest Chemistry Based on Twisted Dimeric Architectures by Adjusting Space Constraints

“…2,2':6',2''-terpyridine (tpy) derivatives have been widely used to construct numerous novel supramolecular structures [54][55][56][57][58][59] with special functions, including catalysis, 60,61 medicine, 62 sensing, 63,64 smart materials, 65,66 and optoelectronic devices. [67][68][69] However, the octahedral coordination geometry of the tpy-M(II)-tpy complex can cause significant steric hindrance, which limits the application in the formation of mechanically interlocked structures based on coordination-directed instead of templating.…”