Molecular receptors. Synthesis and x-ray crystal structure of a calix[4] arene tetracarbonate-acetonitrile (1:1) clathrate

Experimental Evidence for Unusual Protonation of Tetraethyl p-tert-Butylcalix[4]arene Tetraacetate and the Most Probable Structure of the Resulting Complex

“…In all the structures obtained, the methyl group of CH 3 CN is centrally immersed in the calixarene cavity which adopts a symmetric conformation, in agreement with X-ray data [21]. Table 1, the respective energy differences of A' and C' from the global minimum B' are again quite analogous to the former case.…”

“…However, there is evidence that Osubstituted calix [4]arenes can act as hosts for acetonitrile inclusion [21][22][23][24][25][26][27][28][29][30][31][32]. Nevertheless, such host-guest interaction does not appear to interfere with a complexation of ions by the polar groups at the lower rim.…”

Synthesis of Novel p-tert-Butylcalix[4]arene Derivative: Structural Characterization of a Methanol Inclusion Compound

“…The calixarene accommodates the methanol molecule between the channels ( Figure 6, Table 2). A similar inclusion compound has been observed in tetraethyl p-tert-butylcalix [4]arene tetracarbonate in which one acetonitrile molecule lies within the cavity [10]. Additionally, N-H···π interactions generate N2-H2N···Cg4 intermolecular interactions that connect the calixarenes ( Figure 6, Table 2).…”

“…Moreover, these compounds may host different molecules or ions within the hydrophobic cavity due to the interactions generated by the aromatic fraction. Different types of guests, including neutral molecules [9] such as acetonitrile [10], and various ions [11] such as the ammonium ion [12], have been reported. The crystal structures of calix[n]arenes makes them attractive building blocks, as they can easily be functionalized as required; for example, p-tert-butylcalix [4]arene is available through the functionalization of the hydroxyl groups (lower rim) or the para positions of the phenyl rings (upper rim).…”

Photocontrol of Complexation of Neutral and Cationic Species by p‐tert‐Butylcalix[4]arene Tetraethyl Ester

“…While it has been reported that calix [4]arenes tightly bind chloroform, benzene, toluene, xylene, anisole and acetonitrile, [19][20][21][22][23] the limited stability of the sodium complexes in some of these solvents precluded their use. [24] Microanalysis of the isolated complexes indicated that for each of the NaI, NaSCN, NaIO 4 and NaBPh 4 complexes isolated from MeCN, a solvent molecule was also present and these complexes are henceforth denoted as NaX-1·MeCN (X = I -, SCN -, BPh 4 -, IO 4 -).…”