Homothiacalix[4]arenes: Synthetic Exploration and Solid‐State Structures

Abstract

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.

Actuated Conformational Switching in a Single Crystal of a Homodithiacalix[4]arene

“…The compound I (Scheme ) was obtained by applying the concept of dynamic covalent chemistry (DCC), an attractive approach whereby a reversible reaction is performed under equilibrium control, yielding the desired molecule in a selective way, in this case a macrocycle with covalent disulfide bonds (for details, see the Supporting Information) 6. It resembles a previously reported homothiacalix[4]arene 7. This, combined with our interest in macrocycle synthesis,8 spurred our interest in finding a procedure to introduce a second bridging S atom into the macrocyclic ring, aimed at increasing its size and flexibility.…”

A minimized motile machinery for Mycoplasma genitalium

“…While the 55 kDa protein band is in agreement with the expected mass of P32:mCherry fusion protein, the 37 kDa protein band is the result of the hydrolysis of the temperature sensitive acylimine bond found in the mCherry chromophore (Fig. S3; Gross et al ., ; Thomas et al ., ). Remarkably, it was also detected an increase in the amounts of P32 protein, suggesting that the fusion may stabilize the P32 protein in Δmg491‐P32ch cells or alternatively that the P32 protein was itself an additional proteolysis product of the fluorescent fusion.…”

Synthesis and post-functionalization of alternate-linked-meta-para-[2n.1n]thiacyclophanes

“…Based on our previous one-pot procedure towards homothiacalixarenes [12], we now report the development of an alternate meta-para- thiacyclophane which could be post-functionalized.…”

“…Our group has experience in the synthesis of homothiacalix[ n ]arenes, a subclass of the thiacalix[ n ]arenes that has so far received little attention compared to other homoheteracalix[ n ]arenes [10–11]. Homothiacalix[4]arenes were successfully synthesized via nucleophilic substitution and homodithiacalix[4]arenes by dynamic covalent chemistry [12–14]. Functionalization of homothiacalix[4]arenes was made possible by changing the precursors before macrocyclization (Scheme 1) [12].…”

“…Homothiacalix[4]arenes were successfully synthesized via nucleophilic substitution and homodithiacalix[4]arenes by dynamic covalent chemistry [12–14]. Functionalization of homothiacalix[4]arenes was made possible by changing the precursors before macrocyclization (Scheme 1) [12]. …”