Metastable 9‐Fluorenone: Blueshifted Fluorescence, Single‐Crystal‐to‐Single‐Crystal Reactivity, and Evaluation as a Multimodal Fingermark Visualization Treatment

Abstract

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.

Negative Result: Assessing tropolone and its derivatives as chemical fingermark developers on paper surfaces

“…It is hoped that the chemical insights outlined in this work lead to new chemical strategies and reagents that generate improved contrast and are free of the presented drawbacks. While classed as a negative result, this work complements recent chemical studies in the field of fingermark visualisation, including an analogous negative result using 6-(N,N-dimethylamino)fulvene [14], the successful application of hydrolysed Nile blue A [15], functionalisation of both ninhydrin and 1,8-diazafluoren-9-one [16], the development of nanoparticle reagents [17,18], and the growing number of metal [19][20][21][22], and chemical [23,24], vapour-deposition methodologies.…”

Interpol review of fingermarks and other body impressions (2019 – 2022)

“…Preliminary/Pilot studies – Several compounds to be applied in solution were proposed to detect fingermarks on various substrates, mostly non-porous: AIE-active molecules or complexes [ 230 , 245 , [379] , [380] , [381] , [382] , [383] , [384] , [385] , [386] , [387] , [388] ], benzothiazole derivatives [ 389 ], conjugated cationic polymers in solution [ 390 ], di-aqua tris(thenoyltrifluoroacetonate) europium III complex [ 391 ], dye-doped amphiphilic conjugated polymer micelles [ 392 ], dye-doped octasilsesquioxane hybrids [ 393 , 394 ], phenolic ligands chelated with metal ions [ 395 ], sequential processing involving the lifting of fingermarks by a cellulose membrane followed by immersion in water or chemical imaging [ 218 ], tetraphene derivatives [ 396 ]. Other reagents or mechanisms were also proposed: deposition of metallic films (i.e., copper, chromium, and aluminium) using magnetron sputtering [ 397 ], soot from camphor [ 398 ], sublimation of 9-fluorenone under vacuum [ 399 ].…”

Volatilised pyrene: A phase 1 study demonstrating a new method of visualising fingermarks with comparisons to iodine fuming

“…The latter method could be made fluorescent by subsequent dye staining [3,4], and more recently inherently luminescent cyanoacrylate fuming reagents, such as Polycyano UV, have been developed that enable one-step fluorescent fuming [5,6]. Recently newer, more experimental means of fuming have been investigated, such as ninhydrin sublimation [7], lanthanide complex sublimation [8], and sublimation of purely-organic fluorophores such as 9fluorenone [9]. This premise was established by Almog and Gabay who explored fuming of fluorophores such as anthracene and perylene to visualise fingermarks using UV radiation, with a particular emphasis on development of paper substrates [10].…”