Metastable 9-Fluorenone: Blueshifted 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-to-single-crystal (SCSC) transformation to reach the ground state form (GS9F) over approximately 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 nonporous surface. This approach identified three different modes of fluorescent fingermark visualization using 9-fluorenone.

Harnessing volatile luminescent lanthanide complexes to visualise latent fingermarks on nonporous surfaces.

Two commercially-available terbium and europium complexes, EuFOD and TbTMHD, provide luminescent visualisation of latent fingermarks placed on nonporous surfaces via sublimation. This is demonstrated using UV radiation from a forensic light source. The method was optimised on metal foil, with other archetypal nonporous surfaces (i.e. glass, ceramic) also suited to this method.