Abstract
The biologically relevant arenes ethyl salicylate and salicylic amide as well as the fluorescent coumarin and pyrene units were functionalized with a cyclopentadiene unit. The Re and 99mTc complexes of the latter two were synthesized and fully characterized. During crystallization of the ligands, [2+2] and [6+6] cycloadditions were observed for the cyclopentadiene modified coumarin. A light-induced mechanism, supported by DFT calculations, is proposed for these reactions. The fluorescent properties of the coumarin and pyrene based cyclopentadienes and their corresponding Re complexes were investigated .