Photometric Detection of Nitric Oxide Using a Dissolved Iron(III) Corrole as a Sensitizer

The potential of an iron(III) corrole complex for use in the detection of nitric oxide (NO) was investigated. The reversible conversion of an dissolved iron(III) corrole to its corresponding nitrosyl complex using gaseous nitric oxide was monitored by UV/Vis spectroscopy. The spectral differences between both coordination compounds were used to determine photometrically small amounts of nitric oxide in the sub‐parts‐per‐million range. The spectral changes due to NO binding were assigned to charge‐transfer transitions arising upon NO coordination and were analyzed in detail with support from quantum chemical calculations. Finally, films of the iron(III) corrole were deposited on quartz glass. Thus, the great potential of iron(III) corroles for the development of advanced, highly sensitive and low‐energy‐consuming photonic sensing devices was demonstrated. NO hiding from this sensor: Reversible binding of nitric oxide to an iron(III) corrole induces spectral changes close to the Soret absorption band, thus enabling photometric nitric oxide detection (see figure). Sensitive photometric detection in the picomolar range was possible using this amphiphilic iron(III) corrole. The amphiphilicity allows for self‐assembly of the complex into thin solid films, which will be developed for sensing applications.