Assembly of an A₆L₆ Anion Trigonal Antiprism and Binding of Glucopyranosides and Polyethylene Glycols (PEGs)

Abstract

Anion-coordination-driven assembly (ACDA) has proven to be a very effective strategy for the construction of polyhedral structures. Here we demonstrate that variation of the "angle" of the backbone of C 3 -symmetric tris-bis(urea) ligands, from triphenylamine to triphenylphosphine oxide, results in the change of the final construct from an A 4 L 4 tetrahedron to a highernuclearity, A 6 L 6 trigonal antiprism (A = anion, herein PO 4 3À ; L = ligand). Most interestingly, this assembly features a huge hollow internal space that is divided into three compartments: one central cavity and two large outer pockets. This multi-cavity character enables the binding of different guests, namely monosaccharides or polyethylene glycol molecules (PEG600, PEG1000 and PEG2000), respectively. The results prove that anion coordination by multiple hydrogen bonds may provide both sufficient strength and flexibility, thus making possible the formation of complicated structures with adaptive guest binding ability.

Peripheral Control of the Assembly and Chirality of Anion-Based Octanuclear Cubes by Cation–π Networks

“…In recent years, anion-coordination-driven assembly (ACDA) as a new strategy has been successfully employed to construct supramolecular architectures with desirable geometry and functions. , By using bis-bis­(urea) ligands and phosphate anion, a series of well-organized A 2 n L 3 n “aniono” assemblies (A = phosphate anion, L = ligand) have been obtained, including triple helicate (A 2 L 3 ), tetrahedron (A 4 L 6 ), bicapped trigonal antiprism (A 8 L 12 ), and a few other architectures. It is noticed that the “peripheral” templating effect by which the templates are located on the outside of the cage but are closely attached to the host often plays a key role in determining the outcome structure. ,, This may arise from the specific properties of anion-based structures, e.g., the lability of anion coordination through multiple hydrogen bonds and existence of plenty of side cavities/clefts, which enable more adaptive peripheral guest binding.…”

Study on the gelation and sustained release effect of the thermosensitive material TPGS1000

“…With the increase of polymerization degree, its chain length and molecular weight also increase 11 . According to the molecular weight, polyethylene glycol 400 (PEG 400 ), polyethylene glycol 600 (PEG 600 ), polyethylene glycol 1000 (PEG 1000 ), polyethylene glycol 2000 (PEG 2000 ), polyethylene glycol 4000 (PEG 4000 ) and polyethylene glycol 6000 (PEG 6000 ) were commonly used 12,13 . Among them, PEG 1000 is the most widely studied and applied 14 .…”