Chiral expression from molecular to macroscopic level via pH modulation in terbium coordination polymers

Chiral expression from the molecular to macroscopic level is common in biological systems, but is difficult to realise for coordination polymers (CPs). The assembly of homochiral CPs in both crystalline and helical forms can provide a bridge for understanding the relationship between the molecular and macroscopic scales of chirality. Herein, we report homochiral helices of [Tb( R - or S -pempH) 3 ]∙2H 2 O ( R - or S -1 ) (pempH 2 = (1-phenylethylamino)methylphosphonic acid) and their crystalline counterparts ( R - or S -3 ), which are formed at different pH of the reaction mixtures under hydrothermal conditions. By combining the experiments and molecular simulations, we propose that the formation of helices of R -1 or S -1 occurs via a hierarchical self-assembly route, which involves twisted packing due to the geometric incompatibility of the different types of chains. The observed chiral transcription from molecules to morphologies is significant for understanding bio-related self-assembly processes on the nano- to macro-scale. In biological systems it is common for molecular chirality to be expressed at the macroscopic level, but such translation is difficult to achieve in synthetic systems. Here, the authors synthesise homochiral terbium-based coordination polymers with both helical and crystalline morphologies.