Investigations into Chain Length Control over Solid-State Pyrogallol[4]arene Nanocapsule Packing

Abstract

Dedicated to Prof. Dr Ir. David N. Reinhoudt on his retirement.Upon crystallising a series of pyrogallol[4]arenes from ethyl acetate as hydrogen bonded nanocapsules, structural study allows for the determination of the dependence of inter-capsule spacing on the chain length present at the lower rims of these 'bowl-shaped' molecules. Surprisingly, these nanocapsules pack closest together when a hexyl chain length is employed, and reasons for this phenomenon are suggested.

A Synthetic Ion Channel Derived from a Metallogallarene Capsule That Functions in Phospholipid Bilayers

“…[10] The minor differences between our structure and that published arise from slight variations in the undecyl chain positions; our result is therefore not shown here. The crystal structure did reveal that the capsule has six openings of approximately 3.8 diameter on opposite faces.…”

“…Crystallization of 1 from EtOAc, as previously reported by Atwood and co-workers gave the hexameric, hydrogenbonded capsule 2 (1 6 ). [10] Crystallization from a mixture of CH 3 CN and EtOAc also afforded 2. Atwood and co-workers have recently revealed the remarkable property of Calkylpyrogallol [4]arenes to undergo addition of metal ions and form metal-organic nanocapsules.…”

Mixed metal-organic nanocapsules

“…Ethyl acetate is the solvent of choice in harvesting single crystals of the Calkylpyrogallol [4]arene hydrogen-bonded nanocapsules, through which even the quantitative conversion from monomers into nanocapsules has been attained [32]. Acetonitrile has also been a good solvent for both nanocapsule formation, and the cocrystallization of probe molecules on the capsule interior ( Fig.…”

Pyrogallol[4]arenes Show Highly Variable Amphiphilic Behavior at the Air–Water Interface Dependent Upon Side Chain Length and Branching

“…The rccc isomers are usually easy to isolate even if they crystallize in the hexameric capsular arrangement. [39] The compounds used in this study were obtained by previously reported procedures or they were prepared and characterized as described in the Experimental Section. They are: tetramethylpyrogallol [4]arene [28] (MePg or C 1 Pg, 1), tetraethylpyrogallol [4]arene [28] (EtPg or C 2 Pg, 2), tetrapropylpyrogallol [4]arene [40] (PrPg, 3), tetra(isopropyl)pyrogallol [4]arene [34] (iPrPg, 4), tetraA C H T U N G T R E N N U N G (3-pentyl)pyrogallol [4]arene [34] (3-C 5 Pg, 5), tetraA C H T U N G T R E N N U N G (n-hexyl)pyrogallol [4]arene [31] (C 6 Pg, 6), [4]arene [28] (C 9 Pg, 8), and tetra(n-dodecyl)pyrogallol [4]arene [41] (C 12 Pg, 9).…”