Two-Dimensional Chemiresistive Covalent Organic Framework with High Intrinsic Conductivity

Abstract

This paper describes the synthesis of a novel intrinsically conductive two-dimensional (2D) covalent organic framework (COF) through the aromatic annulation of 2,3,9,10,16,17,23,24-octa-aminophthalocyanine nickel­(II) and pyrene-4,5,9,10-tetraone. The intrinsic bulk conductivity of the COF material (termed COF-DC-8) reached 2.51 × 10–3 S/m, and increased by 3 orders of magnitude with I2 doping. Electronic calculations revealed an anisotropic band structure, with the possibility for significant contribution from out-of-plane charge-transport to the intrinsic bulk conductivity. Upon integration into chemiresistive devices, this conductive COF showed excellent responses to various reducing and oxidizing gases, including NH3, H2S, NO, and NO2, with parts-per-billion (ppb) limits of detection (for NH3 = 70 ppb, for H2S = 204 ppb, for NO = 5 ppb, and for NO2 = 16 ppb based on 1.5 min exposure). Electron paramagnetic resonance spectroscopy and X-ray photoelectron spectroscopy studies suggested that the chemiresistive response of the COF-DC-8 involves charge transfer interactions between the analyte and nickelphthalocyanine component of the framework.

A Stable and Conductive Metallophthalocyanine Framework for Electrocatalytic Carbon Dioxide Reduction in Water

“…This result is consistent with other reported values, indicating that the formation of CO 2À intermediate via electron transport from COF skeletons to CO 2 is the rate-determining step. [12] Figure 5 a shows the p structures of conductive CoPc-PDQ-COF and its catalytic cycle of electrochemical CO 2 reduction by cobalt phthalocyanine, which is also supported by CV measurements (Supporting Information, Figure S13). Meanwhile, the monomeric [NH 2 ] 8 CoPc and commercial CoPc exhibited inferior Tafel slopes of 122 mV decade À1 (Figure 4 d, blue curve) and 125 mV decade À1 (Figure 4 d, black curve), respectively.…”

A Stable and Conductive Metallophthalocyanine Framework for Electrocatalytic Carbon Dioxide Reduction in Water

“…The stability originates from the robust phenazine ring that serves as the linkage to connect CoPc and PDQ consisting of stable phthalocyanine and pyrene backbones. Phenazine linkage has been widely used to construct stable heterocyclic polymers and COFs . Compared to other phenazine‐linked analogue, CoPc‐PDQ‐COF decreases structural defects by improving crystallinity as evidenced by a narrow PXRD peak width.…”

Dynamic Covalent Synthesis of Crystalline Porous Graphitic Frameworks

“…Indeed, pyrazine formation has been deemed as an irreversible synthetic dead-end due to aromatic stabilization. With few exceptions, [18][19][20][21][22] previous implementations of similar crosslinking chemistry only resulted in amorphous microporous polymers, 23,24 as reflected in their featureless powder X-ray diffraction (PXRD) patterns. Provided the condensation reaction can be rendered reversible, it may allow error-checking and self-healing to facilitate the growth of crystalline frameworks.…”