title: Fluorescent rhenium-naphthalimide conjugates as cellular imaging agents.
abstract: A range of biologically compatible, fluorescent rhenium-naphthalimide conjugates, based upon the rhenium fac-tricarbonyl core, has been synthesized. The fluorescent ligands are based upon a N-functionalized, 4-amino-derived 1,8-naphthalimide core and incorporate a dipicolyl amine binding unit to chelate Re(I); the structural variations accord to the nature of the alkylated imide with ethyl ester glycine (L(1)), 3-propanol (L(2)), diethylene glycol (L(3)), and benzyl alcohol (L(4)) variants. The species are fluorescent in the visible region between 505 and 537 nm through a naphthalimide-localized intramolecular charge transfer, with corresponding fluorescent lifetimes of up to 9.8 ns. The ligands and complexes were investigated for their potential as imaging agents for human osteoarthritic cells and protistan fish parasite Spironucleus vortens using confocal fluorescence microscopy. The results show that the specific nature of the naphthalimide structure serves to control the uptake and intracellular localization of these imaging agents. Significant differences were noted between the free ligands and complexes, with the Re(I) complex of L(2) showing hydrogenosomal localization in S. vortens.
authors.affiliation: School of Chemistry, Main Building, Cardiff University , Cardiff CF10 3AT, Cymru/Wales, U.K.
authors.forename: Emily E
authors.initials: EE
authors.lastname: Langdon-Jones
authors.forename: Nadine O
authors.initials: NO
authors.lastname: Symonds
authors.forename: Sara E
authors.initials: SE
authors.lastname: Yates
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hayes
authors.forename: David
authors.initials: D
authors.lastname: Lloyd
authors.forename: Rebecca
authors.initials: R
authors.lastname: Williams
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Coles
authors.forename: Peter N
authors.initials: PN
authors.lastname: Horton
authors.forename: Simon J A
authors.initials: SJ
authors.lastname: Pope
mesh_terms: D002460:Cell Line; D002477:Cells / Q000648:ultrastructure*; D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D053644:Naphthalimides / Q000737:chemistry*; D012211:Rhenium / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D053644:Naphthalimides; D012211:Rhenium