FREE shipping to on qualifying orders when you spend or more, processed by Ossila BV. All prices ex. VAT. Qualifying orders ship free worldwide! Fast, secure, and backed by the Ossila guarantee. It looks like you are visiting from , click to shop in or change country. Orders to the EU are processed by our EU subsidiary.

It looks like you are using an unsupported browser. You can still place orders by emailing us on info@ossila.com, but you may experience issues browsing our website. Please consider upgrading to a modern browser for better security and an improved browsing experience.


Product Code B1711-5g
Price $125 ex. VAT

Quality assured

Expert support

Volume discounts

Worldwide shipping

Fast and secure


A fluorinated indole

Used as a synthesis intermediate for APIs and polyindoles in application of biosynthesis, OLEDs, DSSCs and semiconductors


5-Fluoroindole (CAS number 399-52-0), derived from indole, a bicyclic heterocycle, has a fluorine substituent at 5-position. 5-Fluoroindole is applied as a fluorine labelled indole in tryptophan biosynthesis which can be monitored by 19F NMR. The conversion of 5-fluoroindole to 5-fluorotryphtophan is catalyzed by an enzyme synthase with L-serine in proliferating Escherichia coli cells.

5-Fluoroindole is also used to synthesize polyindoles. The oxidative potential of 5-fluoroindole is 1.05 V vs SCE (saturated calomel electrode), which allows it to be easily polymerized electrochemically. The fluorinated polyindoles show conductivity of 7.1 × 10-2 S/cm as well as redox properties. Polymers of 5-fluoroindole also exhibit blue light emission in fluorescent spectroscopy, suggesting their potential applications in OLEDs.

Multiple functional groups

Multiple functional groups

For facile synthesis

Fluorinated building block

Fluorinated indole building block

For drug discovery, OLEDs, and semiconductors

Worldwide shipping for 399-52-0

Worldwide shipping

Quick and reliable shipping

High purity 399-52-0

High purity

>98% High purity

General Information

CAS Number 399-52-0
Chemical Formula C8H6FN
Full Name 5-Fluoro-1H-indole
Molecular Weight 135.14 g/mol
Synonyms N/A
Classification / Family Fluorinated building block, Heterocyclic building block, APIs, OLEDs, DSSCs, Semiconductors

Chemical Structure

5-Fluoroindole chemical structure, CAS 399-52-0
5-Fluoroindole chemical structure, CAS 399-52-0

Product Details

Purity 98%
Melting Point Tm = 45 °C – 48 °C
Appearance Off-white to pale beige powder

MSDS Documentation

5-Fluoroindole MSDS Sheet5-Fluoroindole MSDS Sheet

Literature and Reviews

  1. Low-potential electrochemical polymerization of 5-fluoroindole and characterization of its polymers, G. Nie et al., J. Electroanal. Chem., 604(2), 125−132(2007); DOI: 10.1016/j.jelechem.2007.03.010.
  2. Assessing the applicability of 19F labeled tryptophan residues to quantify protein dynamics, C. Krempl et al., J. Biomol. NMR, 77, 55−67(2023); DOI: 10.1007/s10858-022-00411-2.
  3. Modulation of the La/Lb mixing in an indole derivative: a position-dependent study using 4-, 5-, and 6-fluoroindole, J. Wilke et al., J. Phys. Chem. A, 121, 1597−1606(2017); DOI: 10.1021/acs.jpca.6b12605.
  4. Multiomics analysis provides insight into the laboratory evolution of Escherichia coli toward the metabolic usage of fluorinated indoles, F. Agostini et al., ACS Cent. Sci., 7, 81−92(2021); DOI: 10.1021/acscentsci.0c00679.
  5. Polymer-induced biofilms for enhanced biocatalysis, P. Adoni et al., Mater. Horiz., 9, 2592(2022); DOI: 10.1039/d2mh00607c.

To the best of our knowledge the information provided here is accurate. The values provided are typical at the time of manufacture and may vary over time and from batch to batch. Products may have minor cosmetic differences (e.g. to the branding) compared to the photos on our website. All products are for laboratory and research and development use only.

Return to the top