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Monitoring the thermodynamically-controlled formation of diimide-based resin-attached rotaxanes by gel-phase HR MAS 1H NMR spectroscopy.

Mullen KM, Johnstone KD, Webb M, Bampos N, Sanders JK, Gunter MJ

Department of Chemistry, School of Science and Technology, the University of New England, Armidale, NSW 2351, Australia.

The thermodynamically controlled self-assembly of rotaxane and pseudorotaxane systems consisting of (i) a naphthodiimide thread unit terminated at one end with a pyridine ligand, and covalently linked at the other to a gel-phase polystyrene resin support, (ii) a dinaphtho-crown ether shuttle unit, and (iii) a ruthenium carbonyl metalloporphyrin stopper unit, is investigated by high resolution magic angle spinning proton (HR MAS 1H) NMR spectroscopy. The effects of variable concentration of the solution-phase components, the temperature, and added Li+ and Na+ ions are described, and the limitations of the technique are addressed. The dynamic behaviour is compared directly to the solution-phase analogues, where a bulky stopper group is substituted for the polystyrene resin bead.

Published 4 January 2008 in Org Biomol Chem, 6(2): 278-86.
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