Design of Cu(II) Nucleotide Coordination Complex by Engineered π-π Stacking Interaction: Crystal Structure and Enantiomer Recognition of Amino Acids

The stereoselective recognition of chiral amino acids remains a fundamental challenge in biomimetic chemistry. Here, we report a single crystal of copper(II) coordination complex (C-1), which functions as a receptor, engineered by leveraging π-π stacking interactions as the primary mechanism for discriminating enantiomers of tryptophan (Trp) and histidine (His). Constructed from deoxycytidine monophosphate (dCMP) and 1,10-phenanthroline ligands, C-1 adopts a one-dimensional architecture that selectively binds l- and d-enantiomers through stereospecific aromatic interactions. UV–visible titrations reveal a 10-fold increase in absorbance for l-Trp compared to d-Trp, while circular dichroism (CD) spectra exhibit distinct Cotton effects, directly attributed to π-π stacking between the indole/imidazole side chains and the aromatic framework of C-1. DFT calculations reveal π-π binding energies (−0.49 to −1.20 eV) as the driving force for enantioselective recognition, with geometric alignment enhancing stabilization of both l- and d-enantiomers. By prioritizing π-driven interactions over hydrogen bonding, C-1 achieves precise enantioselectivity, comparable to biological systems. This work establishes π-π stacking as a design principle for synthetic receptors, facilitating adaptive chiral sensing based on noncovalent molecular recognition.