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  • 1.
    Andres, Julien
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Expanding the Versatility of Dipicolinate-Based Luminescent Lanthanide Complexes: A Fast Method for Antenna Testing2015In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 54, no 17, p. 8174-8176Article in journal (Refereed)
    Abstract [en]

    A dipicolinate (dpa)-based platform for the rapid testing of potential lanthanide-sensitizing antennae was developed; 4-methyl-7-O-alkylcoumarin-appended dpa could sensitize four lanthanides. The platform could be used to estimate the photophysical properties of a more difficult-to-prepare 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid based structure carrying the same antenna.

  • 2.
    Arkhypchuk, Anna I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Synthesis and Characterization of Ferrocenyl Chlorins, 1,1'-Ferrocene-Linked Chlorin Dimers, and their BODIPY Analogues2017In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, no 5, p. 3044-3054Article in journal (Refereed)
    Abstract [en]

    We present the synthesis and characterization of meso-ferrocenyl-substituted hydroporphyrins (chlorins) and 1,1' -linked chlorin dimers. The dipyrromethane chlorin precursors were also transformed into Fc-substituted BODIPYs and 1,1'-ferrocenyl-linked BODIPY dimers. The chlorin dimers were studied by 1D and 2D NMR experiments and DFT calculations, which showed that their solution structures were dependent on the central metal. Monomeric and dimeric Ni(II) chlorins had similar H-1 NMR spectra. Monomeric and dimeric free base, Zn(II), and Pd(II) chlorins, on the other hand, showed significantly more different spectra. The eclipsed conformer of the free base chlorin dimer was calculated to be energetically more favored than the open form. The chlorin and BODIPY fluorescence emissions were quenched in the Fcsubstituted compounds; these could be recovered by oxidation of the Fe(II) center. Cyclic voltammetry showed up to five oxidation waves for the free base chlorin dimer, which suggests that the macrocycles were not behaving independently of each other.

  • 3.
    Arkhypchuk, Anna I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Kovacs, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Isolation and Characterization of a Monoprotonated Hydroporphyrin2018In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 48, p. 7051-7056Article in journal (Refereed)
    Abstract [en]

    A simple protocol for the controlled preparation of mono- and diprotonated hydroporphyrins (chlorins) is presented. The chlorins carried 10-aryl groups with electron-neutral (phenyl), electron-donating (p-OMe-C6H4) or electron-withdrawing (pentafluorophenyl) substituents. The protonation reactions were readily followed by UV/Vis absorption spectroscopy, enabling the determination of the first (4.8-5.3) and second pK(a)'s (1.7-0.5). Both mono- and diprotonated species were fully characterized by H-1 NMR spectroscopy, which, in combination with theoretical studies, showed that these macrocycles were significantly distorted in solution. A 10-phenyl-substituted monoprotonated chlorin was characterized by X-ray crystallography. This is the first structurally characterized hydroporphyrin monocation, and the first crystal structure of a sterically unencumbered singly protonated tetrapyrrole. The photostabilities of the mono- and diprotonated 10-phenylchlorins were measured upon irradiation into their Soret bands; protonation yielded increased photostabilities.

  • 4.
    Borbas, Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Synthesis and characterization of lanthanide-tetrapyrrole dyads2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 248Article in journal (Other academic)
  • 5.
    Bornhof, Anna-Bea
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Xiong, Ruisheng
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Rational Synthesis of 2-Bromoporphyrins and 2,12-Dibromoporphyrins2017In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 23, p. 12908-12913Article in journal (Refereed)
    Abstract [en]

    Bromoporphyrins were prepared by the metal-mediated self-condensation of brominated 1-formyldipyrromethanes. Depending on the conditions, Mg(II)-2,12-dibromoporphyrin and Mg(II)-2-bromoporphyrin could be obtained in up to 11% and 17% isolated yield, respectively. Zn(II) was also a viable templating metal. The positions of the bromine substituents were confirmed by 2D-NMR spectroscopic analysis and the X-ray crystal structure of a derivative. Suzuki and Sonogashira reactions of the bromoporphyrins yielded 2-substituted or 2,12-disubstituted porphyrins with red-shifted absorption and emission spectra. This method provides access to the minimalist core of beta-mono- and beta,beta'-disubstituted porphyrins from readily available starting materials.

  • 6.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    The role of photoinduced electron transfer in the quenching of sensitized Europium emission2018In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 364, p. 1-9Article, review/survey (Refereed)
    Abstract [en]

    Lanthanide (Ln) complexes equipped with a light-harvesting antenna can undergo numerous processes upon light excitation of the chromophore. Some of these, e.g., energy transfer to the Ln are beneficial for Ln luminescence, while others, e.g., interactions with O-H oscillators, are detrimental. Eu(III) is the most reducible of the Ln(III) ions, with a reduction potential of E(Ln(II)/Ln(III)) = -0.35 V vs NHE for the hydrated ions. This means that the Eu(II) redox state is relatively easily accessible by reduction with a range of excited state aromatics, such as are present in luminescent Ln complexes carrying a light harvesting antenna. Electron transfer almost always results in diminished Eu emission quantum yields, and is therefore undesirable; however, it is usually not taken into consideration during complex design. Here, we evaluate the role of Eu complex design for electron transfer. We also discuss strategies for diminishing this quenching pathway, including lowering the reducing power of the antenna excited state, and increasing the stability of the +3 oxidation state of Eu. Finally, we review applications of Eu(II) and photoexcited Eu(II).

  • 7.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Kiraev, Salauat
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Highly emissive Eu- and Tb-emitting bioconjugatable complexes of octa- and nonadentate macrocyclic ligandsManuscript (preprint) (Other academic)
  • 8.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Lu, Xi
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Meszaros, Livia S.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Marjam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Andres, Julien
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Photophysics of Coumarin and Carbostyril-Sensitized Luminescent Lanthanide Complexes: Implications for Complex Design in Multiplex Detection2017In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, no 16, p. 5756-5767Article in journal (Refereed)
    Abstract [en]

    Luminescent lanthanide (Ln(III)) complexes with coumarin or carbostyril antennae were synthesized and their photophysical properties evaluated using steady-state and time-resolved UV-vis spectroscopy. Ligands bearing distant hydroxycoumarin-derived antennae attached through triazole linkers were modest sensitizers for Eu(III) and Tb(III), whereas ligands with 7-amidocarbostyrils directly linked to the coordination site could reach good quantum yields for multiple Ln(III), including the visible emitters Sm(III) and Dy(III), and the near-infrared emitters Nd(III) and Yb(III). The highest lanthanide-centered luminescence quantum yields were 35% (Tb), 7.9% (Eu), 0.67% (Dy), and 0.18% (Sm). Antennae providing similar luminescence intensities with 2-4 Ln-emitters were identified. Photoredox quenching of the carbostyril antenna excited states was observed for all Eu(III)-complexes and should be sensitizing in the case of Yb(III); the scope of the process extends to Ln(III) for which it has not been seen previously, specifically Dy(III) and Sm(III). The proposed process is supported by photophysical and electrochemical data. A FRET-type mechanism was identified in architectures with both distant and close antennae for all of the Lns. This mechanism seems to be the only sensitizing one at long distance and probably contributes to the sensitization at shorter distances along with the triplet pathway. The complexes were nontoxic to either bacterial or mammalian cells. Complexes of an ester-functionalized ligand were taken up by bacteria in a concentration-dependent manner. Our results suggest that the effects of FRET and photoredox quenching should be taken into consideration when designing luminescent Ln complexes. These results also establish these Ln(III)-complexes for multiplex detection beyond the available two-color systems.

  • 9.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mathieu, Emilie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Kiraev, Salauat
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Andres, Julien
    Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Controlling the Yb sensitization pathway in luminescent complexes through the modulation of the Yb(II)/Yb(III) redox potentialManuscript (preprint) (Other academic)
  • 10.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Mathieu, Emilie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Kiraev, Salauat
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Demeyere, Ellen
    Sipos, Agnes
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Controlling photoinduced electron transfer in luminescent europium complexesManuscript (preprint) (Other academic)
  • 11.
    Kovacs, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Phipps, Dulcie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Highly luminescent lanthanide complexes sensitised by tertiary amide-linked carbostyril antennae2018In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 31, p. 10702-10714Article in journal (Refereed)
    Abstract [en]

    Carbostyrils are among the most widely used sensitising antennae for luminescent lanthanides; they afford bright complexes with Eu and Tb, and can also sensitise the emissions of the less commonly used Sm, Dy, Yb and Nd. Systematic studies on the effect of structural variations on the photophysical properties and lanthanide sensitising abilities of carbostyrils can therefore have a large impact. We replaced the secondary amide linker that connects the metal binding site to the antenna with a carboxymethyl-substituted tertiary amide. Eight Tb and Eu complexes were prepared. All had higher lanthanide luminescence quantum yields (phi(Ln)) than their secondary amide analogues; three Tb emitters had phi(Tb) > 40%. Eu complexes had phi(Eu) up to 11.6%. The antenna singlet and triplet excited states are slightly shifted, while the metal coordination sphere is unchanged by the introduction of the carboxymethyl group.

  • 12. Laakso, Johanna
    et al.
    Rosser, Geraldine A.
    Szijjarto, Csongor
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Beeby, Andrew
    Borbas, Eszter K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Synthesis of Chlorin-Sensitized Near Infrared-Emitting Lanthanide Complexes2012In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 51, no 19, p. 10366-10374Article in journal (Refereed)
    Abstract [en]

    Lanthanide (Yb3+, Nd3+) complexes equipped with red-absorbing hydroporphyrin (chlorin) antennae were synthesized and characterized. The syntheses are scalable, highly modular, and enable the introduction of different chlorins functionalized with a single reactive group (COOH or NH2). Absorption maxima were dependent on chlorin substitution pattern (monomeso aryl or dimeso aryl) and metalation state (free base or zinc chelate). The complexes benefit from dual chlorin (610-639 nm) and lanthanide (980 or 1065 nm for Yb- or Nd-complexes, respectively) emission in the biologically relevant red and near IR region of the spectrum.

  • 13.
    Mathieu, Emilie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Sipos, Agnes
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Demeyere, Ellen
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Phipps, Dulcie
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Sakaveli, Dimitra
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Lanthanide-based tools for the investigation of cellular environments2018In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 72, p. 10021-10035Article, review/survey (Refereed)
    Abstract [en]

    Biological probes constructed from lanthanides can provide a variety of readout signals, such as the luminescence of Eu(III), Tb(III), Yb(III), Sm(III) and Dy(III), and the proton relaxation enhancement of Gd(III) and Eu(II). For numerous applications the intracellular delivery of the lanthanide probe is essential. Here, we review the methods for the intracellular delivery of non-targeted complexes (i.e. where the overall complex structure enhances cellular uptake), as well as complexes attached to a targeting unit (i.e. to a peptide or a small molecule) that facilitates delivery. The cellular applications of lanthanide-based supramolecules (dendrimers, metal organic frameworks) are covered briefly. Throughout, we emphasize the techniques that can confirm the intracellular localization of the lanthanides and those that enable the determination of the fate of the probes once inside the cell. Finally, we highlight methods that have not yet been applied in the context of lanthanide-based probes, but have been successful in the intracellular delivery of other metal-based probes.

  • 14.
    Ottosson, Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    AROMATICITY A light-switched yin and yang pair2015In: Nature Chemistry, ISSN 1755-4330, E-ISSN 1755-4349, Vol. 7, no 5, p. 373-375Article in journal (Other (popular science, discussion, etc.))
  • 15. Pershagen, Elias
    et al.
    Borbas, Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Analyte-switchable singlet oxygen generating lanthanide complexes2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. 186-INOR-Article in journal (Other academic)
  • 16. Pershagen, Elias
    et al.
    Borbas, Eszter K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Lanthanide-based luminescent probes for the detection of enzymatic activity2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 247Article in journal (Other academic)
  • 17.
    Pershagen, Elias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Designing reactivity-based responsive lanthanide probes for multicolor detection in biological systems2014In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 273, p. 30-46Article, review/survey (Refereed)
    Abstract [en]

    Strategies for the design and synthesis of responsive luminescent probes based on lanthanide complexes are surveyed. The sensitive detection of analytes ranging from ions to small molecules to large biomolecules such as enzymes in complex biological milieu drives the quest for even more selective probes with improved photophysical properties and broad availability for non-specialists. Here, reactivity-based probes, i.e. those in which the sensing event is accompanied by the breaking of a covalent bond are reviewed, with an emphasis on the strategies that could be generalized to the detection of additional analytes. Syntheses providing advanced cyclen-based ligands with minimum effort, as well as those that enable post-complexation modification of lanthanide-bound structures are presented. (C) 2013 Elsevier B.V. All rights reserved.

  • 18.
    Pershagen, Elias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Multiplex detection of enzymatic activity with responsive lanthanide-based luminescent probes2015In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 54, no 6, p. 1787-1790Article in journal (Refereed)
  • 19. Pershagen, Elias
    et al.
    Nordholm, Johan
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Luminescent Lanthanide Complexes with Analyte-Triggered Antenna Formation2012In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 134, no 24, p. 9832-9835Article in journal (Refereed)
    Abstract [en]

    A new strategy for accessing analyte-responsive luminescent probes is presented. The lanthanide luminescence of Eu and Tb centers is switched on by the analyte-triggered formation of a sensitizing antenna from a nonsensitizing caged precursor. As the cage can be freely varied, an array of probes for different analytes (pd(0/2+), H2O2, F-, beta-galactosidase) can be created from the same core structure. The probe design affords nanomolar to micromolar detection limits, provides the capability to detect two analytes in parallel, and can be utilized to monitor enzymatic activity in live cells.

  • 20.
    Pershagen, Elias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Szijjarto, Csongor
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Borbas, Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Biological tools based on trivalent lanthanides2013In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 246, p. 350-INOR-Article in journal (Other academic)
  • 21.
    Szijjarto, Csongor
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Pershagen, Elias
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Functionalisation of lanthanide complexes via microwave-enhanced Cu(I)-catalysed azide-alkyne cycloaddition2012In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, no 25, p. 7660-7669Article in journal (Refereed)
    Abstract [en]

    Cu-I-catalysed azide-alkyne cycloaddition reactions were used to functionalise lanthanide(III)-complexes (Ln; La, Eu and Tb) incorporating alkyne or azide reactive groups. Microwave irradiation significantly accelerated the reactions, enabling full conversion to the triazole products in some cases in 5 min. Alkyl and aryl azides and alkyl and aryl alkynes could all serve as coupling partners. These reaction conditions proved efficient for cyclen-tricarboxylates and previously unreactive cyclen-tris-primary amide chelates. The synthesis of heterobimetallic (Eu/Tb, EuTb17 and Eu/La, EuLa17) and heterotrimetallic (Eu/La/Eu) complexes was achieved in up to 60% isolated yield starting from coumarin 2-appended alkynyl complexes Tb16 or La16 and an azido-Eu complex Eu4, and bis-alkynyl La-complex La5 and Eu4, respectively. EuTb17 displayed dual Eu-III and Tb-III-emission upon antenna-centred excitation.

  • 22.
    Szijjarto, Csongor
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Pershagen, Elias
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Ilchenko, Nadia O.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    A Versatile Long-Wavelength-Absorbing Scaffold for Eu-Based Responsive Probes2013In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 19, no 9, p. 3099-3109Article, review/survey (Refereed)
    Abstract [en]

    Coumarin-sensitized, long-wavelength-absorbing luminescent EuIII-complexes have been synthesized and characterized. The lanthanide binding site consists of a cyclen-based chelating framework that is attached through a short linker to a 7-hydroxycoumarin, a 7-B(OH)2-coumarin, a 7-O-(4-pinacolatoboronbenzyl)-coumarin or a 7-O-(4-methoxybenzyl)-coumarin. The syntheses are straightforward, use readily available building blocks, and proceed through a small number of high-yielding steps. The sensitivity of coumarin photophysics to the 7-substituent enables modulation of the antenna-absorption properties, and thus the lanthanide excitation spectrum. Reactions of the boronate-based functionalities (cages) with H2O2 yielded the corresponding 7-hydroxycoumarin species. The same species was produced with peroxynitrite in a x106107-fold faster reaction. Both reactions resulted in the emergence of a strong approximate to 407nm excitation band, with concomitant decrease of the 366nm band of the caged probe. In aqueous solution the methoxybenzyl caged Eu-complex was quenched by ONOO. We have shown that preliminary screening of simple coumarin-based antennae through UV/Vis absorption spectroscopy is possible as the changes in absorption profile translate with good fidelity to changes in EuIII-excitation profile in the fully elaborated complex. Taken together, our results show that the 7-hydroxycoumarin antenna is a viable scaffold for the construction of turn-on and ratiometric luminescent probes.

  • 23.
    Vithanarachchi, Sashiprabha M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Kovacs, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Synthesis and photophysical characterization of luminescent lanthanide complexes of nucleotide-functionalized cyclen-and dipicolinate-based ligands2017In: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 460, p. 148-158Article in journal (Refereed)
    Abstract [en]

    Luminescent Eu(III)-and Tb(III)-complexes based on functionalized tetraazamacrocycle (cyclen) or dipicolinic acid (dpa) metal binding sites, and carrying 20-or 50-linked uridine moieties were prepared. The light-harvesting antennae were either a coumarin (in the cyclen-based architectures) or the dpa-moiety itself. Antenna excitation resulted in metal-centered emission for all complexes. The presence of the uridine resulted in less intense lanthanide emission compared to non-nucleotide-modified reference compounds. Nd(III)-complexes of cyclen ligands carrying a uridine but without a sensitizing antenna were also synthesized; these are envisioned as energy transfer acceptors to the Eu(III)-complexes. The possibility for Eu-to-Nd energy transfer was probed. The reported complexes are models for oligonucleotide- attached lanthanide probes. (C) 2016 The Author(s). Published by Elsevier B.V.

  • 24.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Andres, Julien
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Scheffler, Kira
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Borbas, Eszter K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Synthesis and characterisation of lanthanide-hydroporphyrin dyads2015In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 44, no 6, p. 2541-2553Article in journal (Refereed)
    Abstract [en]

    Fluorescence spectroscopy is in many ways the ideal tool for the interrogation of complex biological systems, as it is non-invasive, sensitive, and offers high spatiotemporal resolution. For biomedical imaging luminescent probes absorbing and emitting in the red-to-near infrared (NIR) region are best suited to maximise tissue penetration and minimise damage to cellular components. NIR-emitting lanthanides (Ln) sensitised with red-absorbing antennae are promising candidates for these applications, assuming the challenges of poor photophysical properties and tedious syntheses of the complexes are overcome. Chlorins are porphyrin-type tetrapyrroles with intense red absorption. Recently chlorins have been shown to sensitise Yb and Nd emission when incorporated into Ln-complexes. Here we expand on our previous work, and explore the effect of chlorin structure, metallation state, chlorin-Ln-complex linker length and mode of attachment on the properties of chlorin-Ln complexes. As chlorin absorption bands are similar to 20 nm fwhm and readily tunable, a deeper understanding of structure-property relationships would enable the use of chlorin-Ln complexes in multicolour imaging using antenna-specific excitation. A detailed description of antenna and complex syntheses and photophysical characterisation is given. A number of challenges were identified, which will have to be addressed in future studies to enable multicolour imaging using the NIR-emitting lanthanides.

  • 25.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Arkhypchuk, Anna I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Synthetic Molecular Chemistry.
    Attempted syntheses of N-confused hydroporphyrins through modified Lindsey routes2019In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 23, no 4-5, p. 589-598Article in journal (Refereed)
    Abstract [en]

    Unlike N-confused porphyrins which are well-known and extensively studied tetrapyrroles, N-confused hydroporphyrins are almost unknown, largely because so far they have resisted attempts at rational synthesis. Here, we report our efforts towards the total synthesis of N-confused hydroporphyrins. We have prepared N-confused building blocks analogous to the non-N-confused substrates in the Lindsey synthesis of sparsely substituted chlorins. We have systematically flipped the A, B and C pyrrole rings in the dipyrrolic precursors of the target N-confused macrocycles, preparing in total an N-confused "Western half' (tetrahydrodipyrrin) and two N-confused "Eastern halves" (brominated formyldipyrromethanes). These were subjected to a range of cyclization conditions. While we successfully isolated and identified three macrocyclic products, none of these proved to be the desired N-confused hydroporphyrin.

  • 26.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Arkhypchuk, Anna I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Kovacs, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Directly linked hydroporphyrin dimers2016In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 52, no 58, p. 9056-9058Article in journal (Refereed)
    Abstract [en]

    Directly linked hydroporphyrin (chlorin) dimers were accessed regioselectively from bromochlorins. Versatile 15-borylated chlorins were prepared in excellent yield via Miyaura borylation. Suzuki coupling yielded meso-beta-linked homo- and heterodimers, and meso-blinked dimers. The photophysical and electrochemical properties of the dimers are reported.

  • 27.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Borbas, Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Design, synthesis, and characterization of a hydroporphyrin scaffold for the rational preparation of heterobimetallic lanthanide complexes2014In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 248Article in journal (Other academic)
  • 28.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Excitation- and emission-based multiplexing with near infrared-emitting luminescent lanthanide complexes using red-light excitation2017In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal (Other academic)
  • 29.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC.
    Mild Microwave-Assisted Synthesis of Dipyrromethanes and Their Analogues2015In: Synlett: Accounts and Rapid Communications in Synthetic Organic Chemistry, ISSN 0936-5214, E-ISSN 1437-2096, Vol. 26, no 4, p. 484-488Article in journal (Refereed)
    Abstract [en]

    The Mannich reaction between pyrroles or indoles and Eschenmoser's salt (dimethylmethylideneammonium iodide) forms N,N-dimethylamino-methylated derivatives in good to excellent yields. The reaction is highly regioselective, and for pyrroles both 2- and 3-substituted derivatives could be obtained. The N,N-dimethylaminomethylpyrroles and indoles underwent substitution with pyrrole under microwave irradiation, affording the appropriate dipyrromethanes, N-confused, and indolo-dipyrromethanes in moderate to excellent overall yield.

  • 30.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Bornhof, Anna-Bea
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Arkhypchuk, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Borbas, Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Furan- and Thiophene-Based Auxochromes Red-shift Chlorin Absorptions and Enable Oxidative Chlorin Polymerizations2017In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 17, p. 4089-4095Article in journal (Refereed)
    Abstract [en]

    The de novo syntheses of chemically stable chlorins with five-membered heterocyclic (furane, thiophene, formylfurane and formylthiophene) substituents in selected meso- and beta-positions are reported. Heterocycle incorporation in the 3- and 13-positions shifted the chlorin absorption and emission to the red (up to lambdaem =680 nm), thus these readily incorporated substituents function analogously to auxochromes present in chlorophylls, for example, formyl and vinyl groups. Photophysical, theoretical and X-ray crystallographic experiments revealed small but significant differences between the behavior of the furan- and the thiophene-based auxochromes. Four regioisomeric bis-thienylchlorins (3,10; 3,13, 3,15 and 10,15) were oxidatively electropolymerized; the chlorin monomer geometry had a profound impact on the polymerization efficiency and the electrochemical properties of the resulting material. Chemical co-polymerization of 3,13-bis-thienylchlorin with 3-hexylthiophene yielded an organic-soluble red-emitting polymer.

  • 31.
    Xiong, Ruisheng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Mara, Dimitrije
    Univ Ghent, Dept Chem, L3, Krijgslaan 281,Bldg S3, B-9000 Ghent, Belgium.
    Liu, Jing
    Univ Ghent, Dept Chem, L3, Krijgslaan 281,Bldg S3, B-9000 Ghent, Belgium.
    Van Deun, Rik
    Univ Ghent, Dept Chem, L3, Krijgslaan 281,Bldg S3, B-9000 Ghent, Belgium.
    Borbas, K. Eszter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Excitation- and Emission-Wavelength-Based Multiplex Spectroscopy Using Red-Absorbing Near-Infrared-Emitting Lanthanide Complexes2018In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 35, p. 10975-10979Article in journal (Refereed)
    Abstract [en]

    Multiplex imaging in the red and near-infrared (NIR) should be an enabling tool for the real-time investigation of biological systems. Currently available emitters have short luminescent lifetimes, broad absorption and emission bands, and small Stokes shifts, which limits multiplexing in this region to two colors. NIR-emitting luminescent lanthanide (Ln) complexes carrying hydroporphyrin (chlorin) sensitizing antennae are excitable in the red through the narrow, intense and tunable chlorin absorptions. Both emission- and excitation-based multiplexing are possible, the former by exciting the same antenna appended to different Lns, the latter by attaching different chlorins with nonoverlapping absorptions to the same Ln. The combination of excitation and emission spectroscopies allows for the straightforward differentiation of up to four different complexes.

1 - 31 of 31
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