Ferroceneboronic Acid | CAS 12152-94-2 | ≥95%

Ferroceneboronic Acid ((dihydroxyboryl)ferrocene, ferrocenyl boronic acid, (boronocyclopentadienyl)cyclopentadienyl iron) is a redox-active organometallic boronic acid used in Suzuki cross-coupling, electrochemical saccharide and diol sensing, cyclic-boronate derivatisation, and the synthesis of ferrocene-appended macrocycles. The electron-rich and sterically demanding ferrocenyl group features a reversible Fe(II)/Fe(III) redox couple that remains intact post-coupling, endowing the target molecule with a built-in electrochemical handle rarely found in standard boronic-acid building blocks. The boronic acid forms cyclic esters with 1,2- and 1,3-diols, which is the basis of saccharide-sensing electrochemistry and of cyclic-boronate diol derivatisation in GC/MS and HPLC.

The product may contain small amounts of the cyclic anhydride ferroceneboroxine; under aqueous or basic coupling conditions the two forms re-equilibrate and the impact on yield is minor.

Applications and Reactions

• Suzuki–Miyaura coupling: couples with aryl and heteroaryl halides and triflates to install the ferrocenyl group on organic scaffolds. The reaction tolerates electron-rich, electron-poor, and heteroaryl partners; cyclic voltammetry of the products tracks how each new substituent shifts the ferrocene oxidation potential.
• Electrochemical saccharide and diol sensors: reversible cyclic boronate ester formation with 1,2- and 1,3-diols shifts the ferrocenyl Fe(II)/Fe(III) redox potential. This signal-transduction principle has been used to build amperometric and cyclic-voltammetric sensors for fructose, glucose, and other cis-diol analytes; mono-, bis-, and chiral ferroceneboronic-acid derivatives have been developed on this basis.
• Cyclic boronate derivatisation for GC/MS and HPLC: ferroceneboronic acid reacts with vicinal diols and polyols to form cyclic boronate derivatives. This chemistry has been applied in GC/MS derivatisation and in HPLC with electrochemical detection, where the ferrocenyl unit provides the electroactive label; the determination of brassinosteroids in plant samples is one established example.
• Ferrocene-appended porphyrins and subporphyrins: Suzuki coupling with halogenated porphyrin or subporphyrin precursors gives ferrocenyl macrocycles studied for optical absorption, fluorescence quenching, electronic communication, and reversible ferrocene-centred oxidation.
• Protected and masked boron variants: ferroceneboronic acid has been converted into protected ferrocenylboron derivatives including FcB(dan), FcB(aam), FcBF3K, FcB(MIDA), and triolborate variants, providing better-defined and more easily handled ferrocenylboron reagents for further organometallic synthesis.

Further Reading

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