Publications

Deep-cavity cavitands were shown to undergo carceplex reactions in which two cavitand tetrols were covalently linked using bromochloromethane; the efficiency of the “dimerization” was closely tied to the templating guest molecule incarcerated within the host.

Abstract The endo- and exo-rim positions of deep-cavity cavitand 1 were functionalized by directed ortho metalation (DoM) procedures. A range of electrophilic quenchers led to hosts with ester, phenol and thioether functionality. In each case, a combination of host pre-organization and reaction control resulted in far fewer products than the theoretical sixty-nine. In addition to the nature of the lithiate, functionalization patterns were also dependent on the electrophile, with a general trend that the non-carbon electrophiles examined gave higher degrees of substitution. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Cavitand 1 is sufficiently predisposed to form nano-scale capsules in the presence of templating straight-chain hydrocarbons; quaternary complexes are formed when two copies of smaller guests are encapsulated, whilst larger guests form ternary entities.

The functionalization of deep-cavity cavitands via electrophilic substitution was investigated. In the parent structures, substitution occurs both at the exo position of the bowl-shaped hosts and on the convex face. Little or no endo substitution was observed. In contrast, derivatives in which methyl groups blocked the reaction sites on the convex face reacted selectively at the exo positions.

The water soluble capsule formed by a deep cavity cavitand with eight carboxylic acid groups controls product distribution during photo-Fries rearrangement of naphthyl esters in water by restricting the mobility of primary singletradical pair.

In aqueous solution, a deep-cavity cavitand was shown to self-assemble into dimeric nano-capsules via the sequestration of gaseous-phase hydrocarbons. The sequestration, assembly, and entrapment process was shown to be dependent on the hydrocarbon. Thus, by way of example, butane could be selectively sequestered from a propane−butane mixture.

A deuterated cavitand host was examined for its affinity to a series of guests; for halogenated, preorganized guests binding was significantly stronger than the corresponding protium host.