Interplay between conformational flexibility, intermolecular H-bonding and 3d-metal cation extraction ability in a series of thiacalix[4]arene lower rim disubstituted Schiff base derivatives.

The rational design of organic ligands with the aim to control their binding abilities towards different metal ions can be considered as one of the key concepts in supramolecular coordination chemistry. Regarding the macrocyclic compounds of thiacalix[4]arene family, this can be achieved the targeted modulation of macrocyclic platform rigidity as well as the proper choice of appended binding sites. Four macrocyclic salen-type ligands based on lower rim disubstituted thiacalix[4]arene derivatives, adopted in a cone conformation, bearing highly coordinating iminophenolic or catecholic groups and two -CH- moieties as spacers but presenting different abilities to form H-bonds, were chosen to elucidate the interplay between the conformational flexibility of the macrocyclic ligands, propensity to participate in the intermolecular H-bonding and the extraction ability of 3d-metal cations.

DFT study of the conformation, hydrogen bonds, IR, Raman, and NMR spectra of 1,3-disubstituted p-tert-butylthiacalix[4]arenes.

Context: The molecular design of spatially preorganized molecules is one of the critical issues in organic chemistry. Molecular recognition and multipoint binding define them. They organize nanoscale assemblies and devices and stably form host-guest inclusion complexes.

Liquid-Crystalline Order in the Phosphorus-Containing DenDrimers.

The structure of phosphorus-containing dendrimers has been studied by IR spectroscopy and optical polarization microscopy. The repeating units of dendrimer molecules are mesogens. This property arises from the conjugation of the aromatic ring and the hydrazone group.

Study of the conformation and hydrogen bonds of the p-tetrasulfonatothiacalix[4]arene pentasodium salt by vibrational spectroscopy and DFT.

The vibrational spectra of the p-tetrasulfonatothiacalix[4]arene pentasodium salt (TCAS) and tert-butylthiacalix[4]arene (BuTCA) were studied. Comparison of the TCAS and BuTCA IR spectra allows us to isolate the bands of tert-butyl and sulfonate groups. Geometry, IR and Raman spectra were calculated for conformation cone, partial cone, 1,2-, and 1,3-alternate.

Experimental and DFT investigation of structure and IR spectra of H-bonded associates of p-(3-carboxy-1-adamantyl)thiacalix[4]arene.

The IR spectra of p-(3-carboxy-1-adamantyl)thiacalix[4]arene (1-AdCOOHTC4A) have been studied. IR spectra of crystalline 1-AdCOOHTC4A obtained at room temperature or upon heating to 250 °C or its dilute solutions lack bands of free hydroxyl groups. The frequency of hydroxyl groups at 3377 cm indicates the formation of an intramolecular H-bond along the lower rim of the 1-AdCOOHTC4A molecule.

The key role of the scaffold on the efficiency of dendrimer nanodrugs.

Dendrimers are well-defined macromolecules whose highly branched structure is reminiscent of many natural structures, such as trees, dendritic cells, neurons or the networks of kidneys and lungs. Nature has privileged such branched structures for increasing the efficiency of exchanges with the external medium; thus, the whole structure is of pivotal importance for these natural networks. On the contrary, it is generally believed that the properties of dendrimers are essentially related to their terminal groups, and that the internal structure plays the minor role of an 'innocent' scaffold.