Post‐Modification of the Interior of Porous Shape‐Persistent Organic Cage Compounds

Abstract

Interior decorating: A post‐synthetic method allows porous organic cage compounds to be prepared with functionalized interior cavities. The approach produces modified cage compounds in quantitative yield and opens the possibility of preparing organic alloys with different functionality. The solution‐based technique shows the advantage of solubility, an inherent property of porous materials derived from discrete organic molecules.

Thermally robust and porous noncovalent organic framework with high affinity for fluorocarbons and CFCs

“…Can pyrazole be replaced with other functionalities that could allow the dissection and fine tuning of hydrogen bonding and [p Á Á Á p] stacking effects? Can the structure of 1 be postsynthetically 48,49 (or even presynthetically?) modified through nucleophilic aromatic substitutions of fluorines attached to the aromatic rings with other nucleophiles?…”

Triptycene‐Based Chiral Macrocyclic Hosts for Highly Enantioselective Recognition of Chiral Guests Containing a Trimethylamino Group

“…[11] In this approach, the chiral macrocycles are relatively easy to prepare but the macrocyclic cavities are not fully utilized in most cases.I ntroducing inherent chirality by eliminating any symmetry plane or inversion center in the cavity-shaped macrocycle skeletons [12] is another strategy to build chiral macrocyclic arenes,but the fussy synthesis and difficulty in utilizing the macrocyclic cavities limit their practical applications.R ecently,O goshi and co-workers reported an ew type of planar chiral macrocyclic arene based on pillararenes in which the enantiomeric macrocycles can easily interconvert owing to the rotation of phenylene group. [13] Alternatively,l inking chiral building blocks could provide an efficient and direct way of constructing chiral macrocyclic arenes,b ut no such examples have hitherto been reported.Tr iptycene, [14] with its unique three-dimensional structure, has been proven to be au seful building block for various macrocyclic hosts,i ncluding calixarenes and calixarene analogues. [5a-d, 15] In most cases,h owever, triptycene has merely been employed as ar igid aromatic scaffold to link the functional blocks,s uch as oligo(ethylene glycol) chains or other aromatic fragments.N oa ttention has been paid to macrocyclic hosts based on chiral triptycene building blocks, despite the fact that both 2,6-and 1,5-disubstituted triptycenes are readily available chiral compounds.W es peculated that macrocyclic molecules completely composed of chiral triptycene fragments would have as ymmetrical framework and fixed conformation, and that their unique structures with chiral and electron-rich cavities would help them find significant applications in supramolecular chemistry and other research areas.H owever,t he synthesis of such macrocyclic molecules still remains ac onsiderable challenge.…”

Synthesis and Applications of Porous Organic Cages

“…35 Additionally, tuning the porosity of the bulk solid can be achieved by modifying the internal cavities with functional groups of varying steric demand. 36 Given the intensive hostguest studies that have been undertaken in the field of macrocyclic chemistry, functionalization of the internal pore voids is an area of research that is poised for further development.…”

“…24 Conversely, reducing the accessible internal pore size of the cage via functionalization leads to a reduction in surface area. 36 Furthermore, the interplay between 3D structure and porosity was clearly elucidated in studies where exohedrally functionalized, topologically analogous cages led to dramatic differences in surface area. 26 However, controlling porosity via this strategy remains an ongoing challenge as, in general, the impact of a specific functional group on the crystal structure of the POC cannot be precisely elucidated a priori.…”