Diastereoselective Self-Assembly of Low-Symmetry Pdn L2n Nanocages through Coordination-Sphere Engineering

Metal-organic cages (MOCs) are popular host architectures assembled from ligands and metal ions/nodes. Assembling structurally complex, low-symmetry MOCs with anisotropic cavities can be limited by the formation of statistical isomer libraries. We set out to investigate the use of primary coordination-sphere engineering (CSE) to bias isomer selectivity within homo- and heteroleptic Pdn L2n cages. Unexpected differences in selectivities between alternative donor groups led us to recognise the significant impact of the second coordination sphere on isomer stabilities. From this, molecular-level insight into the origins of selectivity between cis and trans diastereoisomers was gained, highlighting the importance of both host-guest and host-solvent interactions, in addition to ligand design. This detailed understanding allows precision engineering of low-symmetry MOC assemblies without wholesale redesign of the ligand framework, and fundamentally provides a theoretical scaffold for the development of stimuli-responsive, shape-shifting MOCs.

Terpyridine-based metallosupramolecular constructs: tailored monomers to precise 2D-motifs and 3D-metallocages

Comprehensive summary of the recent developments in the growing field of terpyridine-based, discrete metallosupramolecular architectures.

Metal-Ligand Exchange in a Cyclic Array: The Stepwise Advancement of Supramolecular Complexity

Herein, we demonstrate how the supramolecular complexity (evaluated by the degree of self-sorting M) evolves in a chemical cycle of cascaded metallosupramolecular transformations, using abiological self-assembled entities as input signals. Specifically, the successive addition of the supramolecular self-assembled structures S1 and (T2 + S2) to the starting supramolecular two-component equilateral triangle T1 (M = 1) first induced a fusion into the three-component quadrilateral R1 (M = 6) and then to the five-component scalene triangle T3 (M = 16). Upon the addition of the supramolecular input M1 to T3, a notable self-sorting event occurred, leading to regeneration of the triangle T1 along with formation of the scalene triangle T4 (M = 25). This last step closed the cycle of the supramolecular transformations.

Fully reversible three-state interconversion of metallosupramolecular architectures

The reversible switching of a sterically encumbered phenanthroline–Cu⁺–picolinaldehyde trio back and forth between homoleptic and heteroleptic coordination using the relative metal-ion to ligand ratio is the basis for an unprecedented cyclic three-state interconversion of metallacycles.

A seven-component metallosupramolecular quadrilateral with four different orthogonal complexation vertices

The 4-fold completive self-sorting of a ten-component library (7 dissimilar donors and 3 different acceptors) resulted in the clean self-assembly of four dynamic orthogonal complexes that were used as cornerstones in two novel six- and seven-component scalene quadrilaterals.

Cobalt(ii), iron(ii), zinc(ii) and palladium(ii) complexes of di-topic 4′-{4-[bis(2-pyridyl)aminomethyl]phenyl}-2,2′:6′,2′′-terpyridine. Synthetic and X-ray structural studies

A new di-topic hybrid ligand incorporating terpy/dpa domains and the X-ray structures of five of its metal complexes are presented.