Propeller-Shaped Self-Assembled Molecular Capsules: Synthesis and Guest Entrapment

Abstract

Molecular containers or supramolecular capsules are a subject of great interest because of their potential utilizations in various fields of chemistry, medicine, and nanoscience. They have been utilized as nanovessels for reactions and targeted drug delivery in recent years. Cyclotricatechylene (CTC) is a bowl-shaped molecule in its crown structure. It has six phenolic groups as potential hydrogen bond donors. In this work, we utilize this hydrogen bonding capability of CTC to generate supramolecular complexes with hydrogen bond acceptors such as 4,4′-bipyridine, pyrazine, 2,2′-bipyridine, and phenanthroline. These supramolecular entities were studied in the solid state by X-ray crystallography and scanning electron microscopy. They are not soluble in low polar solvents. Therefore, the hydrogen bonding behavior in solution could not be studied by NMR. Except in the case of pyrazine, capsular supramolecular assemblies were formed in all the cases. One of these capsules was studied for guest entrapment. Planar molecules such as naphthalene and pyrene were trapped inside its cavity with a little reorganization of the capsular assembly.

A propeller-shaped μ4-carbonate hexanuclear dysprosium complex with a high energetic barrier to magnetisation relaxation

“…These types of materials with a propeller ligand arrangement have been recently studied for their application in advanced optics and electronics. [39][40][41] Magneto-structural correlations were facilitated by initially investigating the static magnetic behaviour of the Dy 6 complex through direct current (dc) magnetic measurements between 1.8 and 300 K, with an applied dc field of 1000 Oe. The temperature dependence of the χT product can be observed in Fig.…”

The effect of carboxylate position on the structure of a metal organic framework derived from cyclotriveratrylene

“…A capsular arrangement of CTVs in the solid state is uncommon, and although some examples have been shown for cyclotricatechylene (CTC), 42,43 the only examples reported for CTV-based structures incorporate complementary binding groups at their upper rim. 44,45 In this structure, each molecular capsule is composed of one left handed and one right handed [L 2 ] 3− ligand, and when viewed down the c axis it can be seen that these capsules pack into a hexagonal arrangement ( Fig.…”

Self-assembled Cages and Capsules Using Cyclotriveratrylene-type Scaffolds

“…Here a layer of capsule motifs is created by a combination of hostguest binding of anthracene by the (CTC)¢3(phen) hydrogen-bonded complex along with ππ stacking interactions (Figure 11). 52 A variety of coordination polymers that involve CTV, 53 CTC, 43 or CTV-type tripodal ligands 38,40,5457 have been reported. This is of particular interest because the use of molecular hosts as building units for MOFtype materials allows a hierarchy of potential hostguest interactions through embedded molecular-recognition sites alongside framework cavities and channels.…”