Phosphoric Acid Loaded Azo (−NN−) Based Covalent Organic Framework for Proton Conduction

• Published in: Journal of the American Chemical Society Vol. 136; no. 18; pp. 6570 - 6573
• Main Authors: Chandra, Suman, Kundu, Tanay, Kandambeth, Sharath, BabaRao, Ravichandar, Marathe, Yogesh, Kunjir, Shrikant M, Banerjee, Rahul
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.05.2014
• Subjects: boiling; phosphoric acid; schiff bases
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/ja502212v

Two new chemically stable functional crystalline covalent organic frameworkds (COFs) (Tp-Azo and Tp-Stb) were synthesized using the Schiff base reaction between tri­formyl­phloro­glucinol (Tp) and 4,4′-azodi­aniline (Azo) or 4,4′-diamino­stilbene (Stb), respectively. Both COFs show the expected keto-enamine form, and high stability toward boiling water, strong acidic, and basic media. H3PO4 doping in Tp-Azo leads to immobilization of the acid within the porous framework, which facilitates proton conduction in both the hydrous (σ = 9.9 × 10–4 S cm–1) and anhydrous state (σ = 6.7 × 10–5 S cm–1). This report constitutes the first emergence of COFs as proton conducting materials.