Twisted Metal-Amino Acid Nanobelts: Chirality Transcription from Molecules to Frameworks

We have studied the self-assembly process of a typical biocoordination polymer, Ag(I)/cysteine (Cys), with different chiralities of the amino acid. Self-assembly of Ag(I)/L-Cys leads to production of pure right-handed helical nanobelts, whereas Ag(I)/D-Cys gives rise to the "mirror image", i.e., pure left-handed helical nanobelts. As a comparison, racemic Ag(I)/DL-Cys forms a totally different product, two-dimensional achiral nanosheets. Density functional theory simulation revealed that the molecular chirality of Cys is originally programmed in the specific lattice twisting, which further determines the chirality and dimensionality of the assembly products. This understanding will shed light on comprehending chirality transcription in metal-organic frameworks as well as designing chirality-regulated nanosuperstructures.