Synthesis and structural exploration of disulfide bridged [2(n)] pillararene-like molecules.

Disulfide bridged pillararene-like macrocycles were synthesized starting from 1,4-dialkoxybenzene and sulfur monochloride. The structure was determined using X-ray diffraction analysis.

Synthetic and structural exploration of [2(4)]tetrathiacalix[2]arene[2]pyrimidines.

A novel class of two atom bridged metacyclophanes-[2(4)]thiacalix[2]arene[2]pyrimidines-has been synthesized via a straightforward S(N)Ar reaction. The conformational properties and intra-annular dimensions of the [2(4)]thiacalix[2]arene[2]pyrimidines were evaluated by X-ray structure analysis and compared with known homothia- and thiacalixarenes. Post-macrocyclization oxidation of the bridging sulfur moieties resulted in a [2(4)]sulfonylcalix[2]arene[2]pyrimidine, which gave access to an unexplored cavity size among sulfonylcalixarenes.

Homoselenacalix[4]arenes: synthetic exploration and metallosupramolecular chemistry.

Homoselenacalix[4]arenes were synthesized by a [2 + 2] reductive coupling protocol favouring the cyclotetramers. The inner and outer-rim decoration was varied and a bicyclic derivative was prepared by a similar one-pot procedure. Conformational analysis in solution and the solid state showed noticeable differences between the homoselenacalix[4]arenes and the analogous homothiacalix[4]arenes and provided insight into the metal binding potential of the Se-bridged macrocycles. The homoselenacalix[4]arenes were found to bind Ag(I). Complexation was visualized in the solid state and different packing networks were formed depending on the counter ions applied.

Homothiacalix[4]arenes: synthetic exploration and solid-state structures.

Homothiacalix[n]arenes have been largely underexposed compared with related (homo)heteracalixarenes, although their inherent structural features are particularly attractive for supramolecular host-guest chemistry. In this contribution, the synthetic macrocyclization protocols that afford homothiacalix[n]arenes have been reinvestigated and optimized, providing straightforward access to the parent homothiacalix[4]arene skeleton. Moreover, inner-rim (bis and tetrakis) ester functionalization and dimethylenethia bridge oxidation were successfully performed as well. Solution-phase (variable-temperature) NMR spectroscopy studies and solid-state X-ray structures provided complementary information on the conformational features of the novel macrocycles.