title: Heteronuclear Ir(III)-Ln(III) Luminescent Complexes: Small-Molecule Probes for Dual Modal Imaging and Oxygen Sensing.
abstract: Luminescent, mixed metal d-f complexes have the potential to be used for dual (magnetic resonance imaging (MRI) and luminescence) in vivo imaging. Here, we present dinuclear and trinuclear d-f complexes, comprising a rigid framework linking a luminescent Ir center to one (Ir·Ln) or two (Ir·Ln2) lanthanide metal centers (where Ln = Eu(III) and Gd(III), respectively). A range of physical, spectroscopic, and imaging-based properties including relaxivity arising from the Gd(III) units and the occurrence of Ir(III) → Eu(III) photoinduced energy-transfer are presented. The rigidity imposed by the ligand facilitates high relaxivities for the Gd(III) complexes, while the luminescence from the Ir(III) and Eu(III) centers provide luminescence imaging capabilities. Dinuclear (Ir·Ln) complexes performed best in cellular studies, exhibiting good solubility in aqueous solutions, low toxicity after 4 and 18 h, respectively, and punctate lysosomal staining. We also demonstrate the first example of oxygen sensing in fixed cells using the dyad Ir·Gd, via two-photon phosphorescence lifetime imaging (PLIM).
authors.affiliation: Department of Chemistry, University of Sheffield , Sheffield, S3 7HF, United Kingdom.
authors.forename: Atanu
authors.initials: A
authors.lastname: Jana
authors.affiliation: Department of Chemistry, University of Sheffield , Sheffield, S3 7HF, United Kingdom.
authors.forename: Bethany J
authors.initials: BJ
authors.lastname: Crowston
authors.affiliation: Department of Chemistry, University of Sheffield , Sheffield, S3 7HF, United Kingdom.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Shewring
authors.affiliation: Department of Chemistry, University of Sheffield , Sheffield, S3 7HF, United Kingdom.|Department of Oncology & Metabolism, University of Sheffield , Sheffield, S10 2RX, United Kingdom.
authors.forename: Luke K
authors.initials: LK
authors.lastname: McKenzie
authors.affiliation: Department of Oncology & Metabolism, University of Sheffield , Sheffield, S10 2RX, United Kingdom.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Bryant
authors.affiliation: Rutherford Appleton Laboratory, STFC, Research Complex at Harwell, Harwell Science and Innovation Campus , Didcot, OX11 0FA, United Kingdom.
authors.forename: Stanley W
authors.initials: SW
authors.lastname: Botchway
authors.affiliation: Rutherford Appleton Laboratory, STFC, Research Complex at Harwell, Harwell Science and Innovation Campus , Didcot, OX11 0FA, United Kingdom.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Ward
authors.affiliation: School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom.
authors.forename: Angelo J
authors.initials: AJ
authors.lastname: Amoroso
authors.affiliation: Department of Chemistry, University of Sheffield , Sheffield, S3 7HF, United Kingdom.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Baggaley
authors.affiliation: Department of Chemistry, University of Sheffield , Sheffield, S3 7HF, United Kingdom.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Ward
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D007495:Iridium / Q000737:chemistry*; D007811:Lanthanum / Q000737:chemistry*; D049449:Luminescence; D015335:Molecular Probes; D010100:Oxygen / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D015335:Molecular Probes; D007495:Iridium; D007811:Lanthanum; D010100:Oxygen