Lanthanide-containing functional complexes have found a variety of applications in materials science and biomedicine because of their unique electroptical and magnetic properties. However, the poor stability and solubility in water of multicomponent lanthanide organic assemblies significantly limit their practical applications. We report here a series of water-stable anionic Ln2n L3n -type (n = 2, 3, 4, and 5) lanthanide organic polyhedra (LOPs) constructed by deprotonation self-assembly of three fully conjugated ligands (H4L1 and H4L2a/b) featuring a 2,6-pyridine bitetrazolate chelating moiety. The outcomes of the LOPs formation reactions were found to be very sensitive toward the reaction conditions including base, metal source, solvents, and concentrations as characterized by a combination of NMR, high-resolution ESI–MS and X-ray crystallography. Ligands H4L2a/b manifested an excellent sensitization toward lanthanide ions (Ln = EuIII and TbIII), with high luminescent quantum yields for Tb8L2a 12 (Φ = 11.2% in water) and Eu8L2b 12 (Φ = 76.8% in DMSO) measured in polar solvents. Furthermore, due to the giant molecular weight and rigidity of the polyhedral skeleton, Gd8L2b 12 showed a very high longitudinal relaxivity (r 1) of 400.53 mM–1S–1. The performance of Gd8L2b 12 as potential magnetic resonance imaging contrast agents (CAs) in vivo was evaluated with much longer retention time in the tumor sites compared with the commercial GdIII-based CAs. Dual-modal imaging potential has also been demonstrated with the mixed Eu/Gd LOPs. Our results not only provide a new design route toward water-stable multinuclear lanthanide organic assemblies but also offer potential candidates of supramolecular-edifices for bioimaging and drug delivery.

Biological macromolecules always function through a collective behavior of the aggregated constituents, which usually are self-assembled together via noncovalent interactions. Likewise, artificial supramolecular assemblies, whose properties and functions are mainly derived from their primary and secondary structures, may also aggregate into high-order architectures with emergent functions not available on the individual components. Here we report the first example of an insulin-like hexamerization of lanthanide triple helicates toward a 4 nm diameter hexameric capsule via consecutive metal-directed and anion-directed assembly processes. Hierarchical chiral-sorting self-assembly endows hexamers with aggregation-induced stability and emission enhancement. Furthermore, emergent guest-encapsulation function and enantioselectivity toward terpene drugs have been realized in the late-formed central cavity of the hexamers. This study not only provides a feasible strategy for constructing sophisticated and multifunctional lanthanide−organic materials but also sheds some light on the self-assembly processes in nature.

Chiral luminescent lanthanide–organic cages have many potential applications in enantioselective recognition, sensing, and asymmetric catalysis. However, due to the paucity of structures and their limited cavities, host–guest chemistry with lanthanide–organic cages has remained elusive so far. Herein, we report a guest-driven self-assembly and chiral induction approach for the construction of otherwise inaccessible Ln4L4-type (Ln = lanthanide ions, i.e., EuIII, TbIII; L = ligand) tetrahedral hosts. Single crystal analyses on a series of host–guest complexes reveal remarkable guest-adaptive cavity breathing on the tetrahedral cages, reflecting the advantage of the variation tolerance on coordination geometry of the f-elements. Meanwhile, noncovalent confinement of pyrene within the lanthanide cage not only leads to diminishment of its excimer emission but also facilitates guest to host energy transfer, opening up a new sensitization window for the lanthanide luminescence on the cage. Moreover, stereoselective self-assembly of either Λ4- or Δ4- type Eu4L4 cages has been realized via chiral induction with R/S-BINOL or R/S-SPOL templates, as confirmed by NMR, circular dichroism (CD), and circularly polarized luminescence (CPL) with high dissymmetry factors (g lum) up to ±0.125.

One important feature of enzyme catalysis is the induced-fit conformational change after binding substrates. Herein, we report a biomimetic water-soluble molecular capsule featuring adaptive structural change toward substrate binding, which offers an ideal platform for efficient photocatalysis. The molecular capsule was coordination-assembled from three anthracene-bridged bis-TPT [TPT = 2,4,6-tris­(4-pyridyl)-1,3,5-triazine] ligands and six (bpy)­Pd­(NO3)2 (bpy = 2,2′-bipyridine). Once substrates bind to its hydrophobic cavity, this capsule would undergo quantitative capsule-to-bowl transformation. Visible-light absorption brought about by both the anthracene units and the charge-transfer absorption on the late-formed quintuple π–π stacked host–guest complex efficiently facilitates aerobic photooxidation for the sulfide guests by visible-light irradiation under mild conditions. Desired turnover numbers and product selectivity (sulfoxide over sulfone) have been achieved by the transformable nature of the catalyst and the hydrophilicity of the sulfoxide product. Such a photocatalytic process enabled by an adaptive coordination capsule and substrates as the allosteric effector paves the way for constructing artificial systems to mimic enzyme catalysis.

We report here a guest‐reaction‐induced mitosis‐like host transformation from a known Pd4L2 cage 1 to a conjoined Pd6L3 twin‐cage 2 featuring two separate cavities. The encapsulation of 1‐hydroxymethyl‐2‐naphthol (G1), a known ortho‐quinone methide (o‐QMs) precursor, within the hydrophobic cavity of cage 1 is found crucial to realize the cage to twin‐cage conversion. Confined G1 molecules within the nanocavity undergo self‐coupling dimerization reaction to form 2,2′‐dihydroxy‐1,1′‐dinaphthylmethane (G2) which then triggers the cage to twin‐cage mitosis. The same conversion also proceeds, in a much faster rate, via the direct templation of G2, confirming the induced‐fit transformation mechanism. The structure of the (G2)2⊂2 host–guest complex has been established by X‐ray crystallographic study, where cis‐ to trans‐ conformational switch on one bridging ligand is revealed.

Metal-adaptive self-assembly and post-assembly transmetallation modification of functional lanthanide-porphyrin hosts were presented.

Artificial hosts with rich conformational dynamics are attractive to supramolecular chemists due to their adaptive guest-binding properties and enzymelike catalytic functions. We report here the adaptive self-assembly and host-guest catalysis of a new watersoluble organo-palladium host (Pd 2 L 2 ) built from a pyridinium-bonded macrocyclic ligand (L) and cisblocked palladium corners (Pd). While the direct selfassembly of L with Pd gives rise to a dynamic mixture of products, both neutral polyaromatic hydrocarbons and an anionic polyoxometalate cluster (W 10 O 32 4À ) can template the dominant formation of the Pd 2 L 2 host. Guest-adaptive conformational changes and induced-fit cavity deformation of the Pd 2 L 2 host have been clearly observed in the crystal structures. Moreover, the installation of the electron-rich W 10 O 32 4À cluster within the cationic redox-active host (W 10 O 32 �Pd 2 L 2 ) facilitates the efficient and selective CÀ H photooxidation of toluene derivatives to aldehyde products under mild conditions, thus representing an ideal platform for green supramolecular catalysis.

By varying the metal/ligand ratio, either dinuclear triple helicates (ΛΛ/ΔΔ-La2LR/S 3) or mononuclear pincer complexes (Λ/Δ-LaLR/S) can be stereo-selectively obtained from the same chiral bistridentate ligand (LR/S). Due to the...