The design of structurally defined heteroleptic coordination cages is a challenging task, and only few examples are known to date. Here we describe a selection approach that allowed the identification of a novel hexanuclear Pd cage containing two types of dipyridyl ligands. A virtual combinatorial library of [Pd n L 2n ](BF 4 ) 2n complexes was prepared by mixing six different dipyridyl ligands with substoichiometric amounts of [Pd(CH 3 CN) 4 ](BF 4 ) 2 . Analysis of the equilibrated reaction mixture revealed the preferential formation of a heteroleptic [Pd 6 L 6 L′ 6 ](BF 4 ) 12 assembly. The complex was prepared on a preparative scale by a targeted synthesis, and its structure was elucidated by single-crystal X-ray diffraction. It features an unprecedented trigonal-antiprismatic cage structure with two triangular Pd 3 L 3 macrocycles bridged by six L′ ligands. A related but significantly larger [Pd 6 L 6 L′ 6 ](BF 4 ) 12 cage was obtained by using metalloligands instead of organic dipyridyl ligands.

A water‐soluble coordination cage was obtained by reaction of Pd(NO3)2 with a 1,3‐di(pyridin‐3‐yl)benzene ligand featuring a short PEG chain. The cavity of the metal‐organic cage contains one nitrate anion, which is readily replaced by chloride. The apparent association constant for chloride binding in buffered aqueous solution is Ka=1.8(±0.1)×105 M−1. This value is significantly higher than what has been reported for other macrocyclic chloride receptors. The heavier halides Br− and I− compete with binding or self‐assembly, but the receptor displays very good selectivity over common anions such as phosphate, acetate, carbonate, and sulfate. A further increase of the chloride binding affinity by a factor of 3 was achieved using a fluorinated dipyridyl ligand.

The threat posed by the presence of artificial volatile organic compounds (VOCs) in the environment is a widely acknowledged fact, both for environmental issues and human health concerns. Ever-increasing production requires the continuous development of technologies toward the removal of these substances. In recent years, metal−organic frameworks (MOFs) have shown a great promise toward the capture of VOCs, but their stability in humid conditions still remains a major challenge, thus hindering their widespread development. To tackle this obstacle, we designed a 3-dimensional and porous MOF, named SION-82, for the capture of small aromatic VOCs, relying solely on π−π interactions. SION-82 captures benzene efficiently (107 mg/g) in dry conditions, and no uptake decrease was observed in the presence of high relative humidity for at least six cycles. Unlike HKUST-1 and MOF-74(Co), SION-82 possesses two vital characteristics toward sustainable benzene capture under humid conditions: moisture stability and reusability. In addition, SION-82 captures benzene under humid conditions more efficiently compared to the hydrolytically stable UiO-66, highlighting the impact of having an active site for benzene capture that is not affected by water. SION-82 can additionally capture other aromatic VOCs, showing pyridine and thiophene uptake capacities of 140 and 160 mg/g, respectively.

Thirteen palladium-ligand assemblies with different structures and topologies were investigated for the ability to bind lithium ions. In one case, the addition of LiBF 4 resulted in a profound structural rearrangement, converting a dincluclear [Pd 2 L 4 ] 4 + complex into a low-symmetry [Pd 4 L 8 ] 8 + assembly with two binding pockets for solvated LiBF 4 ion pairs. The rearrangement could only be induced by Li + , indicating highly specific host-guest interactions. A structural analysis of the [Pd 4 L 8 ] 8 + receptor revealed a compact structure with multiple intramolecular interactions, reminiscent of what is seen for natural and synthetic foldamers.

A water‐soluble coordination cage was obtained by reaction of Pd(NO3)2 with a 1,3‐di(pyridin‐3‐yl)benzene ligand featuring a short PEG chain. The cavity of the metal‐organic cage contains one nitrate anion, which is readily replaced by chloride. The apparent association constant for chloride binding in buffered aqueous solution is Ka=1.8(±0.1)×105 M−1. This value is significantly higher than what has been reported for other macrocyclic chloride receptors. The heavier halides Br− and I− compete with binding or self‐assembly, but the receptor displays very good selectivity over common anions such as phosphate, acetate, carbonate, and sulfate. A further increase of the chloride binding affinity by a factor of 3 was achieved using a fluorinated dipyridyl ligand.