Resorcinarenes

Resorcinarenes have some degrees of freedom for rotation around the C—C bonds of the connecting CHa-groups, which results in five conformations, namely crown, boat, chair, diamond and saddle. The hydroxy groups at the wider rim must be linked in order to fix the receptor in the specific cavitand conformation and to improve binding properties. 

Chiral discrimination of the host-guest interaction can be measured in the gas phase. Resorcin[4]arenes bearing chiral substituents are able to select chiral quaternary ammonium ions. In these cases, complexation experiments were conducted by means of electrospray ionization (ESI) mass spectrometry.  

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Cluster emission, 27 305 Cluster glass transitions, 74 469 Clustering techniques, 6 16-17 Cluster sampling, 26 1018 C-Methylcalix[4]resorcinarene, 74 165 CMOS image sensors, fabrication... 

Covalent R4MX species, that is, antimony(v) bromides ITSbBr (R = Bu, Ph), were encapsulated as guests in hexameric resorcinarene hosts.248 Pentavalent bismuth(v) alkoxides, Ph4BiOR, and organoantimony(v) cyanoximates,... 

Fig. 10 Wave-like ribbon structure of (C-methylcalix[4]resorcinarene).2(4,4 -bipyridine) (CH3CN) with C-methylcalix[4]resorcinarene in a bowl conformation [52]...

The doubly solvated 1 1 adduct of 24 and 2,2 -bipyridine, (C-methylcalix[4]-resorcinarene)(2,2 -bipyridine)(H20)(CH3OH) 32, also features a 2D hydrogen bonded network structure of C-methylcalix[4]resorcinarene and water [64]. There are four intermolecular hydrogen bonds arranged differently to those seen... 

Calixarene and their resorcinarene relatives are similar to CDs with respect to their ability to form a concave cavity in which guests can bind. Calixarenes are conformationally more flexible than the resorcinarenes, and depending on the substituents attached to their wider upper rim or to the narrower lower rim they may exist in a highly-symmetric bowl-shaped, so-called cone conformation or in several other conformations that do not exhibit an as perfect cavity as does the cone conformation (Scheme 9). Cationic guests, such as alkali metal or ammonium ions. 

We will use the name resorc[4]arene to design the tetrameric product obtained from the condensation of resorcinol and aldehyde also named resorcinarene or resorcino-larene... 

Electrochemistry of Guests Inside Resorcinarene Molecular Capsules... 

Figure 3.8 Structures of the resorcinarenes 3 and 4 used in the formation of self-assembled, hexameric molecular capsules.

NMR spectroscopic data in CD2C12 solution verified the encapsulation of cobaltocenium inside a capsule composed of six molecules of resorcinarene 4. From NMR diffusion coefficient measurements, we concluded that the resorcinarene molecular capsules were preformed in CD2CI2 solution51 in the absence of cobaltocenium or any other cationic species. Similar results in CDC13 solution have been reported by Cohen and coworkers.52 53 It is now clear that cationic species are not required to seed the self-assembly of the capsules. 

Figure 3.9 Size comparison between cobatocenium (top left) and the hexameric molecular capsule formed by resorcinarene 3. Resorcinarene 4 would form a much larger capsule due to its longer undecyl feet compared to the methyl feet in 3. (See the color version of this figure in Color Plates section.)...

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