The Rzepa research group is a member of the synthesis section in the department of Chemistry, Faculty of Natural Sciences. The group is interested in molecules, and in particular modelling their shapes, properties and reactions. The example currently showcased below involves modelling the key transition state in the catalytic polymerisation of lactide to polylactide, a new generation of bio-sustainable polymer not dependent on oil. This particular Magnesium-based catalyst produces heterotactic polymer, where the configuration of the lactide units alternates in the polymer chain, in the manner RR, SS, RR, SS, etc. Understanding why this happens was achieved using quantitative modelling, derived from accurate quantum mechanical (density functional) calculations of the reaction mechanism. This was published as: Gibson, Vernon C.; Marshall, Edward L.; Rzepa, Henry S. "A computational study on the ring-opening polymerization of lactide initiated by beta-diketiminate metal alkoxides: The origin of heterotactic stereocontrol", J. Am. Chem. Soc., 2005, 127, 6048-6051. DOI: 10.1021/ja043819b and 10.1021/ja061400a

A second theme has been the exploration of a fundamentally new form of aromaticity which has the property of chirality (dissymetry). These helical aromatics derive from Mobius topologies, and our work has extended the categorisation of such systems from single half twist, to double (lemniscular) systems, and even higher up to six half twists. We have reviewed the area (DOI: 10.1021/cr030092l) and introduced a new topological metric of aromaticity based on writhe (DOI: 10.1021/ja710438j).

Since 1993, we have been pioneers in presenting such chemical stories in Internet-friendly ways. The environment in which the Web page you are currently viewing is embedded unfortunately does not readily lend itself to "molecular interactivity". You are encouraged to also visit an alternative page at www.ch.ic.ac.uk/rzepa/ to view and manipulate a 3D model of the molecule described above, along with much other information about the activities of the group.

Rzepa recently presented his inaugural lecture in chemistry, which can be found here along with his blog.

FOAF Link