American Chemical Society, Journal of the American Chemical Society, 25(137), p. 7970-7973, 2015
DOI: 10.1021/jacs.5b02262
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The quest for enantiopure compounds raises the question of which factors favor conglomerate crystallization over racemate crystallization. Studying nucleation and crystal growth at surfaces with submolecular-resolution scanning tunneling microscopy is a suitable approach to better understand intermolecular chiral recognition. Racemic heptahelicene on the Ag(100) surface shows a transition from homochiral nuclei to larger racemic motifs, although the extended homochiral phase exhibits higher density. The homochiral-heterochiral transition is explained by the higher stability of growing nuclei due to better match of the molecular lattice to the substrate surface. Our observations are a direct visual proof of viable nuclei.