Pair of chiral molecular ladders and successive hydration in single-crystal-to-single-crystal mode

Abstract

Unusual successive two-step crystallization of a pair of chiral coordination polymers was carried out. Self-assembly of Zn(NO₃)₂ with a pair of chiral C₃-symmetric tridentate N-donor ligands (1S,2R-L and 1R,2S-L) produces single crystals consisting of chiral enantiomeric 1D ladder coordination polymers, CH₂Cl₂·2CH₃CN@[Zn₃(NO₃)₆(1S,2R-L)₂] and CH₂Cl₂·2CH₃CN@[Zn₃(NO₃)₆(1R,2S-L)₂], after which the single crystals are transformed into new crystals in their hydrated forms, 2CH₃CN@[Zn₃(NO₃)₆(1S,2R-L)₂(H₂O)₂] and 2CH₃CN@[Zn₃(NO₃)₆(1R,2S-L)₂(H₂O)₂], respectively, under the moisture condition, in the single-crystal-to-single-crystal (SCSC) mode. The crystals consist of hexagonally packed chiral 1D coordination polymers in an enantiomeric arrangement, and their hydration shows a subtle difference depending on the chirality.