1,4-Cubanedicarboxylic acid
[CAS 32846-66-5]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives
• Name: 1,4-Cubanedicarboxylic acid
• Synonyms: cubane-1,4-dicarboxylic acid
• Molecular Formula: C₁₀H₈O₄
• Molecular Weight: 192.17
• CAS Registry Number: 32846-66-5
• EC Number: 809-101-1
• SMILES: C12C3C4C1(C5C2C3(C45)C(=O)O)C(=O)O

Properties

• Density: 2.4±0.1 g/cm³ Calc.^*
• Boiling point: 457.4±45.0 °C 760 mmHg (Calc.)^*
• Flash point: 244.6±25.2 °C (Calc.)^*
• Index of refraction: 2.042 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS06 Danger
• Risk Statements: H301
• Safety Statements: P264-P270-P301+P316-P321-P330-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	3	H301
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319

chemBlink Chemical Story

A cube is an unusual shape for an organic molecule, but cubane turns that geometric idea into a carbon framework. Eight carbon atoms occupy the corners of the cage. In 1,4-cubanedicarboxylic acid, CAS 32846-66-5, two carboxylic acid groups extend from opposite vertices. The result is a compact, rigid connector with two chemically useful ends. Its importance comes from the combination of attachment direction and a three-dimensional hydrocarbon surface.

The two acid groups can lose their acidic protons to provide carboxylate binding sites. Those sites allow the molecule to connect metal-containing units in coordination materials. The cage between them provides a different local environment from a flat aromatic ring. This distinction matters because an adsorbed molecule encounters the inside surface of a porous material, not simply the formula of its linker. A change in the connector can therefore change the character of the space around a guest without requiring an entirely different network design.

A concrete example appeared in 2019, when Macreadie and colleagues reported CUB-5. They combined the cubane-derived dicarboxylate with zinc-oxygen clusters to make a framework related in connectivity to MOF-5. The work associated benzene adsorption with the unusual aliphatic pore environment. It established a materials application for this particular diacid while leaving industrial separation performance as a subject for further investigation.

That result also clarifies what the product is. The free diacid is a molecular building block; CUB-5 is an extended structure assembled from that building block and metal-containing nodes. Measurements on the assembled framework do not describe the adsorption capacity of a bottle of the free acid. Likewise, an ester of the same cage has different functional groups and should not be substituted in a discussion of carboxylate coordination without explaining the conversion.

The broader design lesson is that molecular geometry can be a functional variable. Linker length, the direction of its two ends, and the surface presented between them all help define the eventual material. This makes 1,4-cubanedicarboxylic acid an instructive bridge between cage chemistry and porous-solid research: a small, precisely shaped molecule can help determine the environment inside a much larger structure.

References:
1. Macreadie LK et al. CUB-5: A Contoured Aliphatic Pore Environment in a Cubic Framework with Potential for Benzene Separation Applications. J Am Chem Soc. 2019;141:3828-3832. https://doi.org/10.1021/jacs.8b13639
2. J-GLOBAL. Cubane-1,4-dicarboxylic acid: substance identity, CAS 32846-66-5. https://jglobal.jst.go.jp/en/detail?JGLOBAL_ID=200907005446907788

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