Modulating the Inclusive and Coordinating Ability of Thiacalix[4]arene and Its Antenna Effect on Yb3-Luminescence via Upper-Rim Substitution+

The present work introduces the series of thiacalix[4]arenes (H₄L) bearing different upper-rim substituents (R = H, Br, NO₂) for rational design of ligands providing an antenna-effect on the NIR Yb³⁺-centered luminescence of their Yb³⁺ complexes. The unusual inclusive self-assembly of H₃L⁻ (Br) through Br…π interactions is revealed through single-crystal XRD analysis. Thermodynamically favorable formation of dimeric complexes [2Yb³⁺:2HL³⁻] leads to efficient sensitizing of the Yb³⁺ luminescence for H₄L (Br, NO₂), while poor sensitizing is observed for ligand H₄L (H). X-ray analysis of the single crystal separated from the basified DMF solutions of YbCl₃ and H₄L(NO₂) has revealed the transformation of the dimeric complexes into [4Yb³⁺:2L⁴⁻] ones with a cubane-like cluster structure. The luminescence characteristics of the complexes in the solutions reveal the peculiar antenna effect of H₄L(R = NO₂), where the triplet level at 567 nm (17,637 cm⁻¹) arisen from ILCT provides efficient sensitizing of the Yb³⁺ luminescence.

Intermolecular Interactions Drive the Unusual Co-Crystallization of Different Calix[4]arene Conformations

Crystallization of 5,17-dibromo-11,27,23,25-tetraone-26,28-dipropoxycalix[4]arene results in the rare observation of two different calix[4]arene conformations (partial cone and 1,3-alternate) co-crystallized within the same single crystal X-ray structure. Analysis using 1H and 13C NMR spectroscopy revealed that only a single conformation (the cone) was present in solution, and in contrast to the structures of other reported calix[4]arenes and calix[4]quinones, both conformations of the compound present in this crystal structure have a “pinched” shape, drastically reducing Br-Br separation and associated cavity sizes.

Halogen-bonded architectures of multivalent calix[4]arenes

A 2D halogen bonded network of calixarene macrocycles was obtained by co-crystallization of a 1,3-alternate calix[4]arene as a tetravalent XB donor with a bidentate XB acceptor.

Nuclearity control in calix[4]arene-based zinc(ii) coordination complexes

Three zinc-based coordination complexes were selectively generated in the crystalline phase using a new flexible molecular “tweezers” calix[4]arene derivative ligand decorated with two appended carboxylic moieties and benzyl spacers ((3-4H)).

Weak intermolecular interaction directed assembly of calix[4]arene derivatives

Dimer and tetramer structures of cone-di-formyl-calix[4]arene 16 were formed through weak intermolecular interactions.

2Ch–2N square and hexagon interactions: a combined crystallographic data analysis and computational study

2Ch–2N square and hexagon interactions were extensively investigated by the combination of crystallographic data analysis and computational approaches.

The facile fabrication and formation mechanism of self-assembled spherical 3,3′-diamino-4,4′-azoxyfurazan (DAAF) hierarchical structures

Herein, two insensitive high-explosive DAAF self-assembled structures were obtained by a simple solvent method, and the possible mechanisms were discussed.