Crystal structure and fluorescence sensing properties of tetramethoxyresorcinarene functionalized Schiff bases

Correlating Solution- and Solid-State Structures of Conformationally Flexible Resorcinarenes: Significance of a Sulfonyl Group in Intramolecular Self-Inclusion

The synthesis of tetramethoxyresorcinarene podands bearing p-toluene arms connected by -SO3 - (1) and -CH2 O- (2) linkers is presented herein. In the solid state, the resorcinarene podand 1 forms an intramolecular self-inclusion complex with the pendant p-toluene group of a podand arm, whereas the resorcinarene podand 2 does not show self-inclusion. The conformations of the flexible resorcinarene podands in solution were investigated by variable-temperature experiments using 1D and 2D NMR spectroscopic techniques as well as by computational methods, including a conformational search and subsequent DFT optimisation of representative structures. The 1 H NMR spectra of 1 and 2 at room temperature show a single set of proton signals that are in agreement with C4v symmetry. At low temperatures, the molecules exist as a mixture of boat conformations featuring slow exchange on the NMR timescale. Energy barriers (ΔG≠ 298 ) of 55.5 and 52.0 kJ mol-1 were calculated for the boat-to-boat exchange of 1 and 2, respectively. The results of the ROESY experiments performed at 193 K and computational modelling suggest that in solution the resorcinarene podand 1 adopts a similar conformation to that present in its crystal structure, whereas podand 2 populates a more versatile range of conformations in solution.

2,3-Ethylene-bridged dihomooxacalix[4]arenes: synthesis, X-ray crystal structures and highly selective binding properties with anions

Three novel 2,3-ethylene-bridged p-tert-butyldihomooxacalix[4]arenes 3a–3c were selectively synthesized by direct O-alkylation of p-tert-butyldihomooxacalix[4]arene 1 with excess of 1,2-dibromoethane in controlled basic systems.

A cavity extended water-soluble resorcin[4]arene: synthesis, pH-controlled complexation with paraquat, and application in controllable self-assembly

A novel pH-responsive molecular recognition motif was built between an anionic carboxylate group modified resorcin[4]arene and paraquat in water. We then employed it to fabricate a supra-amphiphile for controllable self-assembly.

Synthesis and characterization of two sulfonated resorcinarenes: a new example of a linear array of sodium centers and macrocycles

Two sulfonated resorcinarenes were synthesized by reacting C-tetra(butyl)resorcinarene or C-tetra(2-(methylthio)ethyl)resorcinarene with formaldehyde in the presence of sodium sulfite. Their structures were determined via FT-IR, ¹H-NMR, ¹³C-NMR and mass spectrometry. Thermal gravimetric analyses of the derivatives were also carried out and revealed the presence of water molecules in the solid state. The sulfonated product of C-tetra(butyl)resorcinarene was characterized by an X-ray crystal structure determination. The asymmetric unit contains eight molecules of water and two of acetone, and analysis indicated that sulfonated resorcinarene prefers a cone configuration (rccc conformation) in the solid state. In the crystal array, classical hydrogen bond interactions O-H···O and intermolecular contacts were observed. In the crystal packing, a linear array of capsules of sulfonated resorcinarenes was generated for a chain of sodium atoms and sulfonate groups.

Preparation and application of tubular assemblies based on amphiphilic tetramethoxyresorcinarenes

A silver nanoparticle/organic hybrid micro-tubular material was prepared by fabricating tetramethoxyresorcinarene tetraaminoamide-functionalized silver nanoparticles on templates of microtubular assemblies.