Metastable 9-Fluorenone: Blue-Shifted Fluorescence, Single-crystal-To-Single-Crystal Reactivity, and Evaluation as a Multimodal Fingermark Visualization Treatment

A metastable form of 9-fluorenone (MS9F) has been characterized using Raman spectroscopy, fluorimetry, and X-ray diffraction techniques. MS9F emits blue fluorescence (λmax = 495

nm) upon 365 nm irradiation and undergoes a single-crystal-tosingle-crystal (SCSC) transformation to reach the ground state form (GS9F) over ca 30 minutes, whereupon it emits the expected green fluorescence. A structure-property relationship for this fluorescent behavior has been posited. MS9F and GS9F were applied as a means of visualizing latent fingermarks on a non-porous surface. This approach identified three different modes of fluorescent fingermark visualization using 9-fluorenone.