# TpPa COFs: β-ketoenamine links that survive acid and base

> TpPa-1 and TpPa-2 are made from 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine or its 2,5-dimethyl analogue. The Schiff base forms first, as the enol-imine, but the proton moves irreversibly from oxygen to nitrogen and only the keto-enamine remains. With no imine bond left to hydrolyse, both COFs survive 9 N hydrochloric acid and boiling water; TpPa-2 also survives 9 N sodium hydroxide.

- Page: https://www.labcanvas.com/templates/covalent-organic-frameworks/tppa-1-ketoenamine-cof-acid-base-stability
- Open in the LabCanvas editor (LabCanvas account): https://www.labcanvas.com/editor.html?template=tppa-ketoenamine-cof-stability
- Updated: 2026-10-14
- Category: Covalent organic frameworks
- Method: Schiff base + tautomerism, bottom-up
- Starting materials: 1,3,5-Triformylphloroglucinol (Tp) with p-phenylenediamine (Pa-1) or 2,5-dimethyl-p-phenylenediamine (Pa-2), in mesitylene/dioxane 1:1
- Product: TpPa-1 and TpPa-2: 2D β-ketoenamine-linked COFs
- Key result: Resistant to 9 N HCl and boiling water (TpPa-1, TpPa-2) and to 9 N NaOH (TpPa-2)
- Figure: 1920 × 1080 px, 87 editable layers (14 generated objects with settings)

## Steps

1. **Schiff base**: Tp and Pa condense in 1:1 mesitylene/dioxane; the expected product is the enol-imine (O–H···N)
2. **Tautomerism**: The proton moves irreversibly from O to N: only the keto-enamine (N–H···O=C) is observed
3. **Layers**: Honeycomb sheets with C=O and N–H facing each other at every link
4. **Stability**: Both resist 9 N HCl and boiling water; TpPa-2 also 9 N NaOH (Kandambeth et al. 2012)

## Strengths

- Reversible step for crystallinity, irreversible step for stability
- No imine bond left to hydrolyse
- Simple, cheap monomers

## Limitations

- Irreversibility limits error correction during growth
- Crystallinity lower than boronate COFs

## Uses

- Catalysis and separations in acid, base or water
- Membranes and electrodes

## References

1. Kandambeth et al., “Construction of Crystalline 2D Covalent Organic Frameworks with Remarkable Chemical (Acid/Base) Stability via a Combined Reversible and Irreversible Route”, J. Am. Chem. Soc. 2012. https://doi.org/10.1021/ja308278w (primary)
2. DeBlase et al., “β-Ketoenamine-Linked Covalent Organic Frameworks Capable of Pseudocapacitive Energy Storage”, J. Am. Chem. Soc. 2013. https://doi.org/10.1021/ja409421d (further reading)
3. Geng et al., “Covalent Organic Frameworks: Design, Synthesis, and Functions”, Chem. Rev. 2020. https://doi.org/10.1021/acs.chemrev.9b00550 (review)

Credit: After Kandambeth et al., JACS 2012 (doi:10.1021/ja308278w) and DeBlase et al., JACS 2013 (doi:10.1021/ja409421d). Patterns computed from the TpPa-1 model; retention after soaking drawn schematically.

## Questions

**What does the “TpPa COFs: β-ketoenamine links that survive acid and base” template show?** TpPa-1 and TpPa-2 are made from 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine or its 2,5-dimethyl analogue. The Schiff base forms first, as the enol-imine, but the proton moves irreversibly from oxygen to nitrogen and only the keto-enamine remains. With no imine bond left to hydrolyse, both COFs survive 9 N hydrochloric acid and boiling water; TpPa-2 also survives 9 N sodium hydroxide.

**What are the steps shown in “TpPa COFs: β-ketoenamine links that survive acid and base”?** 1. Schiff base: Tp and Pa condense in 1:1 mesitylene/dioxane; the expected product is the enol-imine (O–H···N). 2. Tautomerism: The proton moves irreversibly from O to N: only the keto-enamine (N–H···O=C) is observed. 3. Layers: Honeycomb sheets with C=O and N–H facing each other at every link. 4. Stability: Both resist 9 N HCl and boiling water; TpPa-2 also 9 N NaOH (Kandambeth et al. 2012).

**What are the starting materials and the product?** Starting materials: 1,3,5-Triformylphloroglucinol (Tp) with p-phenylenediamine (Pa-1) or 2,5-dimethyl-p-phenylenediamine (Pa-2), in mesitylene/dioxane 1:1. Product: TpPa-1 and TpPa-2: 2D β-ketoenamine-linked COFs.

**Which papers is “TpPa COFs: β-ketoenamine links that survive acid and base” based on?** Kandambeth et al., “Construction of Crystalline 2D Covalent Organic Frameworks with Remarkable Chemical (Acid/Base) Stability via a Combined Reversible and Irreversible Route”, J. Am. Chem. Soc. 2012 (doi:10.1021/ja308278w); DeBlase et al., “β-Ketoenamine-Linked Covalent Organic Frameworks Capable of Pseudocapacitive Energy Storage”, J. Am. Chem. Soc. 2013 (doi:10.1021/ja409421d); Geng et al., “Covalent Organic Frameworks: Design, Synthesis, and Functions”, Chem. Rev. 2020 (doi:10.1021/acs.chemrev.9b00550).

**Can I edit the “TpPa COFs: β-ketoenamine links that survive acid and base” template?** Yes. Open it in the LabCanvas editor: all 87 layers are editable, including 14 generated objects (structures, plots, equipment) with their own settings. Change the text, colours and layout, then export PNG, TIFF, SVG or PDF.

**Do I need an account to use this template?** Not to view it here. To open and edit it, sign in to LabCanvas or create a free account (the free plan keeps one design of each kind). Downloading the figure is part of LabCanvas Pro (US$19 a month or US$199 a year).