Effect of π⋯π interactions on the conductivity of two 1D coordination polymers through one-pot crystallization

Abstract

Herein, we report the syntheses of two Zn(II) coordination polymers (CPs), [Zn(9-aca)₂(pdb)(H₂O)₂]·2(H₂O)·2(CH₃CH₂OH) (CP1) and [Zn(9-aca)₂(pdb)(H₂O)₂]·2(CH₃CH₂OH) (CP2) [H9-aca = 9-anthracenecarboxylic acid and pdb = N,N′-bis(1-pyridine-4-yl-ethylidene)], obtained through one-pot crystallization. Both compounds crystallized in the monoclinic space group P2₁/n with Z = 1. However, the asymmetric unit of CP1 contains EtOH and H₂O in the crystal lattice, while CP2 contains only EtOH in the lattice. Interestingly, CP1 and CP2 form a 1D linear chain structure and exhibit electrical conductivity and Schottky behaviour. However, CP1 exhibits higher conductivity and better Schottky diode formation than CP2, which relates to charge transport through space via π⋯π interactions present in CP1. Theoretical bandgap values, Fermi levels, and electronic properties derived from density functional theory (DFT) calculations, including partial density of states (PDOS) analysis, align with experimental results. This study showcases a new direction for the development and fabrication of electronic devices.