Universal synthesis of metallophthalocyanine covalent organic frameworks as ultra-sensitive multifaceted electrochemical sensor

The universal synthesis of highly stable covalent organic frameworks (COFs) for ultra-sensitive and multi-component electrochemical detection in different scenarios remains a great challenge. Herein, a series of metallophthalocyanine-based two-dimensional (2D) dioxin (DXI)-linked metalophthalocyanine (MPc)-nDXI-COFs (M = Ni, Zn; n = 1, 2) are afforded in high yield (80%–96%) by a facile trace-quinoline assisted one-pot condensation of tetracarbonitrile precursors. Powder X-ray diffraction and electron microscopy investigations disclose their lamellar texture 2D network with AA stacking mode. Experiments and calculation results elucidate that the 2DXI-linked MPc-2DXI-COFs provide the stronger built-in electronic field and more electrostatic/hydrogen bonding adsorption sites than DXI-linked MPc-DXI-COFs, and the lower electrode reaction Gibbs free energy and stronger adsorption of analytes at NiPc than ZnPc unit, which grants NiPc-2DXI-COF excellent sensing properties for various analytes including neurotransmitters, organic pollutants, and heavy metal ions, with high sensitivity and low detection limit of 0.53 to 25.66 nM. Especially in binary and ternary systems and even in real-world conditions, simultaneous multi-component detection could be achieved.