A new [4]carceplex, and a crystal structure and dynamic combinatorial chemistry of a [5]carceplex

A new [4]carceplex (2-guest) is reported. It is composed of two cavitands linked by four disulfide bonds. It forms twistomers, which interconvert on a millisecond timescale. The energy barrier for interconversion of twistomers is guest-dependent. Formation of [4]carceplex 2-guest is template dependent. The selectivity in templates is flat relative to most previous related template work. Larger kin [5]carceplex 1.guests were reinvestigated. A crystal structure confirms the twist between the hemispherical cavitands. Use of a redox buffer allowed dynamic combinatorial chemistry to be performed between pairs of templates. (C) 2009 Elsevier Ltd. All rights reserved.