Modulating Bonding States and Stability of Conductive Coordination Polymers

Conductive coordination polymers (CCPs) could combine the merits of both conductive polymers and metal-organic frameworks (MOFs) and hence have attracted extensive attention for various applications. However, the modulation of their properties is challenging and rarely studied. Herein, three CCPs, denoted as Cu─6O, Cu─6N, and Cu─3O3N, featuring Cu─O₄, Cu─(NH)₄, and Cu─O₂(NH)₂ units respectively, are constructed to systematically investigate the effect of the ligating atoms and bonding states on the properties. Spectroscopic and theoretical analyses reveal that Cu─O bonds are dominated by electrostatic interactions, whereas Cu─N bonds exhibit stronger covalent character, and the mixed Cu─O₂(NH)₂ unit further enhances the overall bond strength by optimizing orbital hybridization and energy matching. Consequently, Cu─6O shows the weakest Cu─X (X═O or NH) bonds, poorest thermal stability and undergoes irreversible degradation upon base conditions at pH above ∼9.5, while also suffering severe structural degradation under electrochemical condition. The degradation mechanism was also revealed. Conversely, the stronger coordination bonds in Cu─6N and Cu─3O3N endow them with superior thermal, chemical, and electrochemical stability. This work highlights the essential role of ligating atoms in determining the bonding states and provides a design principle for developing robust CCPs.