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Self‐assembling systems in nature display remarkable complexity with assemblies of different sub‐units to generate functional species. Synthetic analogues of such systems are a challenge, often requiring the ability to bias distributions that are under thermodynamic assembly control. Using lantern‐type MOCs (metal‐organic cages) as a prototypical self‐assembling system, herein we explore the role that steric bulk plays in controlling the exchange rate of ligands in paddlewheel‐based assemblies, and thus the stability of cages, in competitive self‐assembling scenarios. The effective lifetime of the lantern‐type MOCs varies over an order of magnitude depending on the steric bulk proximal to the metal nodes with lifetimes of the cages ranging from tens of minutes to several hours. The bulk of the coordinating solvents likewise reduces the rate of ligand exchange, and thus yields longer‐lived species. Understanding this subtle effect has implications for controlling the stability of complex assemblies in competitive environments with implications for guest release and application. [ABSTRACT FROM AUTHOR]

The assembly of hydrogen bonded cages using amidinium...carboxylate hydrogen bonding interactions was investigated. A new tris-amidinium hydrogen bond donor tecton based on a tetraphenylmethane scaffold was prepared and its selfassembly with the terephthalate anion studied, and a new tricarboxylate hydrogen bond acceptor tecton was synthesised and its assembly with the 1,3-benzenebis(amidinium) hydrogen bond donor explored. In both cases, molecular modelling indicated that the formation of the cages was geometrically feasible and 1H NMR spectroscopic evidence was consistent with interactions between the components in competitive d6-DMSO solvent mixtures. DOSY NMR spectroscopy of both systems indicated that both components diffuse at the same rate as each other, and diffusion coefficients were consistent with cage formation, and with the formation of assemblies significantly larger than the individual components. An X-ray crystal structure showed that one of the assemblies did not have the desired cage structure in the solid state. [ABSTRACT FROM AUTHOR]

Two dipyridyl ligands, L 3,3 and L 3,4 , have been used in combination with palladium(II) in the construction of metallosupramolecular species that show anion-dependent behavior in solution. A rare example of a low-symmetry ( C 2 h ) lantern-type cage is formed in one instance, [Pd 2 (L 3,3 ) 4 ] 4+ , while the isomeric ligand yields a larger double-walled square complex, [Pd 4 (L 3,4 ) 8 ] 8+ . [Pd 2 (L 3,3 ) 4 ](NO 3 ) 4 was isolated in crystalline form revealing two anions within the interior of the C 2 h -symmetry cage. The cage itself is held together by hydrogen bonding between "head-to-tail" pairs of ligands that reinforces the symmetry generated by the ditopic ligands. In solution, the cage with NO 3 - has sharp 1 H nuclear magnetic resonance (NMR) signals at room temperature, while the BF 4 - analogue has broad signals that sharpen at higher temperatures or upon addition of (Bu 4 N)(NO 3 ), highlighting the importance of the anion in templating or otherwise influencing self-assembly in solution. Altering the substitution position of one of the pyridyl rings yields a more "open" complex, with [Pd 4 (L 3,4 ) 8 ](NO 3 ) 8 being isolated as a crystalline solid. The double-walled square complex has a greater Pd···Pd separation due to the increased angle that the pyridyl groups subtend at the core of the ligand. NMR spectroscopy and mass spectrometry studies suggest a single species in the presence of nitrate but multiple species with tetrafluoroborate.