Liu S, Kondratuk DV, Rousseaux SA. L, Gil-Ramirez G, O’Sullivan MC, Cremers J, Claridge
TD. W, Anderson HL * University of Oxford, UK
Caterpillar Track Complexes in Template-Directed Synthesis and Correlated Molecular
Motion.
Angew. Chem. Int. Ed. 2015;
DOI:
10.1002/anie.201412293
Key words
template-directed synthesis - molecular motion - exchange spectroscopy - porphyrin
nanorings - oligo-pyridines
Significance
Oligo-pyridines have been used as templates to direct the synthesis of zinc-porphyrin
nanorings. The authors showed that a hexapyridyl template directed the synthesis of
a cyclic zinc-porphyrin hexamer, removal of one binding site on the hexapyridyl template
produced a cyclic decamer and removal of two binding sites produced a cyclic octamer.
An interesting discovery of these zinc-porphyrin nanorings is that while the nanorings
are static when they are coordinatively saturated with the binding sites on the pyridine
templates, these assemblies undergo caterpillar track motion when coordinating to
hexapyridyl templates with free binding sites.
Comment
Zinc-porphyrin nanorings were purified by size exclusion chromatography and recycling
gel permeation chromatography (GPC). The caterpillar track motion of these assemblies
was studied by 1D exchange spectroscopy (EXSY) NMR. This is an elegant system demonstrating
the control of correlated motions on molecular scale. Addition of [PdCl2(PhCN)2] halted the caterpillar track motion in these assemblies by binding palladium between
the two hexapyridine templates.
