Unravelling the structure of the C60 and p-But-calix[8]arene complex

Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.The structure of the C60 and p-But-calix[8]arene complex has been reinvestigated, showing an unprecedented continuous layered tetragonal array of fullerenes encapsulated by calixarenes. Electron diffraction data revealed the tetragonal symmetry, with a stepped structure observed by AFM and SEM, and the thickness of the basal plane was measured by XRD, as 2 nm. The molecular simulated arrangement of fullerenes accounts for the ability to take up to ca. 11% of fullerenes C70 in place of the smaller fullerene

Syntheses and characterization of aryl-substituted pyrogallol[4]arenes and resorcin[4]arenes

Thirteen aryl-substituted pyrogallol[4]arene and resorcin[4]arenes structures are synthesized and characterized. The effect of the varying aryl pendent groups on π–π distance, the inward tilt of the pendent –R groups, the twist angle of the pendent –R groups, and the angle between the pendent –R groups is methodically investigated and discussed.</p

Site-Specific Metal Chelation Facilitates the Unveiling of Hidden Coordination Sites in an Fe II/Fe III -Seamed Pyrogallol[4]arene Nanocapsule

Under suitable conditions, C-alkylpyrogallol­[4]­arenes (PgCs) arrange into spherical metal–organic nanocapsules (MONCs) upon coordination to appropriate metal ions. Herein we present the synthesis and structural characterization of a novel FeII/FeIII-seamed MONC, as well as studies related to its electrochemical and magnetic behaviors. Unlike other MONCs that are assembled through 24 metal ions, this nanocapsule comprises 32 Fe ions, uncovering 8 additional coordination sites situated between the constituent PgC subunits. The FeII ions are likely formed by the reducing ability of DMF used in the synthesis, representing a novel synthetic route toward polynuclear mixed-valence MONCs

Metallo-supramolecular capsules

The formation of capsule based architectures on the molecular scale has been of interest to many researchers in recent times. The formation of these assemblies is often challenging and can produce structures on a multi nano-metre scale that can serve specific functions. Some of the approaches used to produce such assemblies are outlined in relation to various building blocks in metal-organic polyhedra, molecular boxes and molecular capsules for example. The last of these has been the focus of our recent studies since the discovery of a hydrogen-bonded nano-capsule based on C-methylresorcin[4]arene, although the molecule also assembles in dimeric capsule motifs. The related pyrogallol[4]arenes display similar behaviour, however a number of metal-organic analogues have recently been synthesised and characterised through a variety of techniques that suggest various assembly processes. These are highlighted in the context of related architectures in order to give a sense of potential for such assemblies that can, in some cases, be assembled instantaneously or very rapidly

Robust and stable pyrogallol[4]arene molecular capsules facilitated <i>via</i> an octanuclear zinc coordination belt

The first metal coordinated pyrogallol[4]arene encapsulating dimer has been synthesised and shows high nuclearity with respect to ZnII, arranged as a polar coordination belt

Ionic dimeric pyrogallol[4]arene capsules

Ionic capsules based on dimeric arrangements of pyrogallol[4]arenes have been structurally authenticated and suggest that there is a degree of flexibility in capsule formation with further potential for multiple guest encapsulation and manipulation in such arrangements

Separation of Active Pharmaceutical Ingredients (APIs) from Excipients in Pharmaceutical Formulations

The active pharmaceutical ingredient (API) may be physically separated from the excipients in a pharmaceutical formulation by making use of the difference in density of the API and that of the excipients. The API may then be fully characterized by standard techniques. In the density separation process, the API is not dissolved, and the crystal form of the API is not changed. As examples, Form I fexofenadine hydrochloride is separated from Allegra Allergy 24 h Tablets, and Form I lansoprazole is separated from Equate Lansoprazole Delayed Release Capsules