Synthesis and photophysical properties of iron-carbonyl complex–coumarin conjugates as potential bimodal IR–fluorescent probes

Abstract

An expedient synthesis of the first examples of iron-carbonyl complex–coumarin conjugates is reported. 7-Amino/7-hydroxycoumarin derivatives have been readily derivatized through an easily implemented single-step reaction involving the tricarbonyl(η5-cyclohexadienyl)iron(1+) cation [(C6H7)Fe(CO)3]+. The scope and limitations of this N-/O-alkylation reaction were also investigated. The fluorescence properties of these novel metal–carbonyl complexes have been studied and support their further use as valuable building blocks in the design of bimodal contrast agents for combined vibrational and fluorescence imaging.