(3,5-Diformylphenyl)boronic Acid

Technical Specifications

Product Description & Scientific Applications

(3,5-Diformylphenyl)boronic acid (3,5-diformylbenzeneboronic acid; 5-boronobenzene-1,3-dicarbaldehyde) is a trifunctional aromatic building block. Two aldehyde groups occupy the 3- and 5-positions and a boronic acid the 1-position. The aldehydes undergo reversible imine (Schiff-base) condensation with primary amines. The boronic acid forms boroxine anhydrides and boronate esters and couples under Suzuki–Miyaura conditions. A single molecule thus supplies two orthogonal, dynamically reversible covalent handles, and it serves as a node and linker in covalent organic frameworks, dynamic covalent polymers and gels, and boron-functional porous materials for separation and molecular recognition.

May contain small amounts of the cyclic anhydride 3,5-diformylphenylboroxine. Under aqueous or basic coupling conditions the two forms re-equilibrate and the impact on yield is minor.

Applications and Reactions

• Imine-linked covalent organic frameworks: the two aldehydes condense with polyamine knots such as 1,3,5-tris(4-aminophenyl)benzene to give crystalline imine-linked frameworks, installing the boronic acid as a pendant group. The pendant boronic acid acts as a hydrogen-bond donor for selective sorption, demonstrated in solid-phase microextraction of trace phthalate esters.
• Dual dynamic-covalent, self-healing materials: both handles form reversible bonds, the boronic acid as boroxine and the aldehydes as dynamic imine. Built into a polydimethylsiloxane network, the doubly dynamic monomer gives a luminescent elastomer with elongation to 4200%, stretch-induced fluorescence chromism from green to cyan, and self-healing within 20 min at room temperature.
• Suzuki–Miyaura cross-coupling: as an arylboronic acid it couples with aryl and heteroaryl halides under palladium catalysis to install the 3,5-diformylphenyl group, the two aldehydes retained as handles for subsequent condensation.
• Boronate esters and diol recognition: the boronic acid condenses reversibly with 1,2- and 1,3-diols, catechols, and saccharides to form cyclic boronate esters, the basis of pH- and sugar-responsive dynamic covalent gels and molecular recognition.
• Aldehyde condensation chemistry: beyond imine formation, the two aldehydes undergo the standard condensations of an aromatic dialdehyde — hydrazone, oxime, and acetal formation — for wider dynamic covalent and reversible-linkage chemistry.
• Protected boronate esters: the boronic acid can be masked as pinacol (Bpin) or MIDA boronates for iterative or orthogonal cross-coupling alongside the aldehyde chemistry.

Further Reading

For boronic acids, boronic esters, organotrifluoroborates, protodeboronation, boroxine content, and Suzuki–Miyaura reagent selection, see NorrChemica's Lab Journal guide: Choosing Your Boron Source for Suzuki–Miyaura Coupling.

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