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A 1 : 2 mixture of Zn‐meso‐tetrakis(4‐dodecyl‐3,5‐dihydroxyphenyl)porphyrin (1‐Zn) and tetrakis(4‐pyridylethynyl)cavitand (2) in C6D6 self‐assembles quantitatively into the doubly cavitand‐capped Zn‐porphyrin capsule 2 ⋅ 1‐Zn ⋅ 2 with two cavities divided by the porphyrin ring via eight ArOH⋅⋅⋅Npy hydrogen bonds. Simultaneous encapsulation of 1‐acetoxy‐3,5‐dimethoxybenzene (G) and 4‐(4‐methylphenyl)pyridine (L2) in 2 ⋅ 1‐Zn ⋅ 2 preferentially occurs to form G/L2@(2 ⋅ 1‐Zn ⋅ 2). A 1 : 1 mixture of 1‐Zn and 2 in the presence of G and L2 self‐assembles into the G‐encapsulating half‐capsule G@(2 ⋅ 1‐Zn) ⋅ L2 with coordination of L2 at the outer side of 2 ⋅ 1‐Zn. A 2 : 2 : 1 mixture of 1‐Zn, 2, and 1,4‐diazabicyclo[2.2.2]octane (L3) in the presence of G self‐assembles preferentially into the G‐encapsulating doubly cavitand‐capped double‐decker Zn‐porphyrin capsule G/G@(2 ⋅ 1‐Zn ⋅ L3 ⋅ 1‐Zn ⋅ 2) with coordination of L3 between two hydrogen‐bonded 1‐Zn subunits. Thus, selective formation of these cavitand–porphyrin capsules can be controlled by the stoichiometry of 1‐Zn and 2 as well as the character of N‐ligands. [ABSTRACT FROM AUTHOR]

A 2 : 4 mixture of tetrakis[4‐(4‐pyridyl)phenyl]cavitand (1) or tetrakis[4‐(4‐pyridyl)phenylethynyl]cavitand (2) and Pd(dppp)(OTf)2 self‐assembles into a homocapsule {12 ⋅ [Pd(dppp)]4}8+ ⋅ (TfO−)8 (C1) or {22 ⋅ [Pd(dppp)]4}8+ ⋅ (TfO−)8 (C2), respectively, through Pd−Npy coordination bonds. A 1 : 1 : 4 mixture of 1, 2, and Pd(dppp)(OTf)2 produced a mixture of homocapsules C1, C2, and a heterocapsule {1 ⋅ 2 ⋅ [Pd(dppp)]4}8+ ⋅ (TfO−)8 (C3) in a 1 : 1 : 0.98 mole ratio. Selective formation (self‐sorting) of homocapsules C1 and C2 or heterocapsule C3 was controlled by guest‐induced encapsulation under thermodynamic control. Applications of Pd−Npy coordination capsules with the use of 1 were demonstrated. Capsule C1 serves as a guard nanocontainer for trans‐4,4′‐diacetoxyazobenzene to protect against the trans‐to‐cis photoisomerization by encapsulation. A chiral capsule {12 ⋅ [Pd((R)‐BINAP)]4}8+ ⋅ (TfO−)8 (C5) was also constructed. Capsule C5 induces supramolecular chirality with respect to prochiral 2,2′‐bis(alkoxycarbonyl)‐4,4′‐bis(1‐propynyl)biphenyls by diastereomeric encapsulation through the asymmetric suppression of rotation around the axis of the prochiral biphenyl moiety. [ABSTRACT FROM AUTHOR]

Cyclic arylene ethynylene hexamer 1, composed of alternating 2,7-anthrylene ethynylene units and meta-phenylene ethynylene units, was synthesized. It shows C3 symmetry and possesses a flat and rigid conformation with a large equilateral triangle-like cavity. Macrocycle 1 self-associates through π-π stacking interactions between the anthracene-containing macrocyclic aromatic cores with indefinite-association constant KE=6980 m−1 in CDCl3 at 303 K. Macrocycle 1 also self-assembles into π-stacked nanofibers in the drop-cast film. [ABSTRACT FROM AUTHOR]

The components of a 1:2 mixture of meso-tetrakis(4-dodecyl-3,5-dihydroxyphenyl)porphyrin ( 1) and a bowl-shaped tetrakis(4-pyridylethynyl)cavitand ( 2) in CDCl3 or C6D6 self-assemble quantitatively into the doubly cavitand-capped porphyrin capsule 2⋅1⋅2 through eight ArOH ⋅⋅⋅Npy hydrogen bonds. Capsule 2⋅1⋅2 possesses two cavities divided by the porphyrin ring and encapsulates two molecules of 1-acetoxy-3,5-dimethoxybenzene ( G) as a guest to form G/ G@( 2⋅1⋅2). Remarkable solvent effect was observed, in which the apparent association constant of 2⋅1⋅2 with G in C6D6 was much greater than that in CDCl3. [ABSTRACT FROM AUTHOR]

Two molecules of cavitand tetraboronic acid and four molecules of various bis(catechol) linkers self-assemble into capsules through the formation of eight dynamic boronic ester bonds. Each capsule has a different cavity size depending on the linker used, and shows particular guest encapsulation selectivity. A chiral capsule made up of the cavitand and a chiral bis(catechol) linker was also constructed. This capsule induces supramolecular chirality with respect to a prochiral biphenyl guest by diastereomeric encapsulation through the asymmetric suppression of rotation around the axis of the prochiral biphenyl moiety. [ABSTRACT FROM AUTHOR]

A C2-symmetrical tetrakis(arylethynyl) cavitand was synthesized. Spontaneous formation of hybrid hydrogen bonded/metal-ligand coordination supramolecular capsules occurs upon mixing 1 with cis-coordinated Pt2+ or Pd2+ metal complexes. The hybrid supramolecular capsules encapsulated neutral guest molecules only in polar solvents. [ABSTRACT FROM AUTHOR]

The self-assembled boronic ester cavitand capsule 3 quantitatively and tightly encapsulates 2,6-diacetoxy-9,10-bis(arylethynyl)anthracene derivatives 4 a- 4 c as highly fluorescent cruciform guests to form complexes 4 a@ 3, 4 b@ 3, and 4 c@( 3)2. The structural features of capsule 3, which possesses two polar bowl-shaped aromatic cavity ends and four large equatorial windows connected by dynamic boronic ester bonds, made it possible to encapsulate cruciform 4 with protection of the reactive anthracene core inside the capsule and with two protruding arylethynyl groups, the π-conjugated arms of compound 4, through two of the equatorial windows of the capsule. Thus, complexes 4 a@ 3, 4 b@ 3, and 4 c@( 3)2 show greater resistance to photochemical reactions in solution and fluorescence quenching in the powder state compared to free guests 4. In addition to the improved photostability, restriction of the free rotation of the arylethynyl groups of guests 4 upon encapsulation results in sharpening of the UV/Vis absorption peaks with a red-shift and a significant increase in some of the two-photon-absorption peaks of complexes 4 a@ 3, 4 b@ 3, and 4 c@( 3)2 compared with free guests 4. [ABSTRACT FROM AUTHOR]

Hybrid supramolecular capsules self-assemble by simultaneously forming hydrogen and metal-ligand coordination bonds on mixing a C2-symmetrical cavitand (calix[4]resorcinarene-based cavitands with ureide and terminal 4-pyridyl units) with platinum or palladium complexes ([Pt(OTf)2] or [Pd(OTf)2] with chelating bisphosphines) in 1:1 ratio. Hemicapsular assemblies formed in the presence of excess amounts of cavitand relative to the platinum or palladium complexes are identified as intermediates in the above self-assembly process by 2D-NOESY spectroscopy. External-anion-assisted encapsulation of a neutral guest, 4,4′-diiodobiphenyl, inside the hybrid supramolecular capsules accompanied conformational changes in the hydrogen-bonding moieties. The in/out exchange ratio of the encapsulated guest depends on the bite angle of the bisphosphine ligand. Addition of DMSO accelerates guest exchange by weakening the hydrogen bonds in the encapsulation complex. Therefore, variations in the structure of the metal complex and amount of polar solvent exert dual control on the dynamics of the guest exchange. [ABSTRACT FROM AUTHOR]

Abstract: Tetra(4-pyridyl)-cavitand 1 and tetrakis(4-hydroxyphenyl)-cavitand 2 self-assemble into a heterodimeric capsule 1·2 via four PhOH⋯pyridyl hydrogen bonds in CDCl3, wherein one molecule of 1,4-disubstituted-benzene as a guest is encapsulated to form a ternary complex, guest@(1·2). The X-ray crystallographic analysis of (methyl p-ethoxybenzoate)@(1·2) confirmed that the methyl ester and ethoxy groups of the encapsulated guest are oriented to the cavity ends of the 1 and 2 units, respectively. The scope and limitation of guest encapsulation in 1·2, including guest-binding selectivity and orientational isomeric selectivity, are described from the viewpoint of size complementarity and CH–π, CH–halogen, and halogen–π interactions between guest and the cavity of 1·2. [Copyright &y& Elsevier]