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Publications (10 of 31) Show all publications
Xiong, R., Arkhypchuk, A. I. & Borbas, K. E. (2019). Attempted syntheses of N-confused hydroporphyrins through modified Lindsey routes. Journal of Porphyrins and Phthalocyanines, 23(4-5), 589-598
Open this publication in new window or tab >>Attempted syntheses of N-confused hydroporphyrins through modified Lindsey routes
2019 (English)In: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, E-ISSN 1099-1409, Vol. 23, no 4-5, p. 589-598Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
WORLD SCI PUBL CO INC, 2019
Keywords
hydroporphyrins, N-confused tetrapyrroles, chlorins, 2+2 condensation, corrins
National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-387228 (URN)10.1142/S1088424619500524 (DOI)000468181100026 ()
Funder
Swedish Research CouncilStiftelsen Olle Engkvist Byggmästare
Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-06-20Bibliographically approved
Xiong, R., Mara, D., Liu, J., Van Deun, R. & Borbas, K. E. (2018). Excitation- and Emission-Wavelength-Based Multiplex Spectroscopy Using Red-Absorbing Near-Infrared-Emitting Lanthanide Complexes. Journal of the American Chemical Society, 140(35), 10975-10979
Open this publication in new window or tab >>Excitation- and Emission-Wavelength-Based Multiplex Spectroscopy Using Red-Absorbing Near-Infrared-Emitting Lanthanide Complexes
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2018 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 35, p. 10975-10979Article in journal (Refereed) Published
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.

National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-365657 (URN)10.1021/jacs.8b07609 (DOI)000444219100011 ()30122038 (PubMedID)
Funder
Swedish Research Council, 2013-4655
Available from: 2018-11-16 Created: 2018-11-16 Last updated: 2018-11-16Bibliographically approved
Kovacs, D., Phipps, D., Orthaber, A. & Borbas, K. E. (2018). Highly luminescent lanthanide complexes sensitised by tertiary amide-linked carbostyril antennae. Dalton Transactions, 47(31), 10702-10714
Open this publication in new window or tab >>Highly luminescent lanthanide complexes sensitised by tertiary amide-linked carbostyril antennae
2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 31, p. 10702-10714Article in journal (Refereed) Published
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.

National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-363106 (URN)10.1039/c8dt01270a (DOI)000441151700043 ()29923567 (PubMedID)
Funder
Swedish Research Council, 2013-4655Swedish Research Council, 2017-04077
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2019-04-16Bibliographically approved
Arkhypchuk, A. I., Orthaber, A., Kovacs, D. & Borbas, K. E. (2018). Isolation and Characterization of a Monoprotonated Hydroporphyrin. European Journal of Organic Chemistry (48), 7051-7056
Open this publication in new window or tab >>Isolation and Characterization of a Monoprotonated Hydroporphyrin
2018 (English)In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 48, p. 7051-7056Article in journal (Refereed) Published
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.

Keywords
Functional organic materials, Chlorin, Tetrapyrrole, Protonation, Absorption, Fluorescence
National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-374119 (URN)10.1002/ejoc.201801472 (DOI)000454532300027 ()
Funder
Swedish Research Council, 2013-4655Stiftelsen Olle Engkvist Byggmästare
Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2019-01-23Bibliographically approved
Mathieu, E., Sipos, A., Demeyere, E., Phipps, D., Sakaveli, D. & Borbas, K. E. (2018). Lanthanide-based tools for the investigation of cellular environments. Chemical Communications, 54(72), 10021-10035
Open this publication in new window or tab >>Lanthanide-based tools for the investigation of cellular environments
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2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 72, p. 10021-10035Article, review/survey (Refereed) Published
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.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-367137 (URN)10.1039/c8cc05271a (DOI)000443956300043 ()30101249 (PubMedID)
Funder
Swedish Research Council, 2017-04077Carl Tryggers foundation
Available from: 2018-11-29 Created: 2018-11-29 Last updated: 2018-11-29Bibliographically approved
Kovacs, D. & Borbas, K. E. (2018). The role of photoinduced electron transfer in the quenching of sensitized Europium emission. Coordination chemistry reviews, 364, 1-9
Open this publication in new window or tab >>The role of photoinduced electron transfer in the quenching of sensitized Europium emission
2018 (English)In: Coordination chemistry reviews, ISSN 0010-8545, E-ISSN 1873-3840, Vol. 364, p. 1-9Article, review/survey (Refereed) Published
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).

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2018
Keywords
Lanthanide, Europium, Photoinduced electron transfer, Quenching, Single electron reduction
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-357323 (URN)10.1016/j.ccr.2018.03.004 (DOI)000430524800001 ()
Funder
Swedish Research Council, 2013-4655
Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-08-16Bibliographically approved
Xiong, R. & Borbas, K. E. (2017). Excitation- and emission-based multiplexing with near infrared-emitting luminescent lanthanide complexes using red-light excitation. Paper presented at 253rd National Meeting of the American-Chemical-Society (ACS) on Advanced Materials, Technologies, Systems, and Processes, APR 02-06, 2017, San Francisco, CA. Abstract of Papers of the American Chemical Society, 253
Open this publication in new window or tab >>Excitation- and emission-based multiplexing with near infrared-emitting luminescent lanthanide complexes using red-light excitation
2017 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 253Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2017
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-377535 (URN)000430569104150 ()
Conference
253rd National Meeting of the American-Chemical-Society (ACS) on Advanced Materials, Technologies, Systems, and Processes, APR 02-06, 2017, San Francisco, CA
Available from: 2019-02-25 Created: 2019-02-25 Last updated: 2019-02-25Bibliographically approved
Xiong, R., Bornhof, A.-B., Arkhypchuk, A., Orthaber, A. & Borbas, E. (2017). Furan- and Thiophene-Based Auxochromes Red-shift Chlorin Absorptions and Enable Oxidative Chlorin Polymerizations. Chemistry - A European Journal, 23(17), 4089-4095
Open this publication in new window or tab >>Furan- and Thiophene-Based Auxochromes Red-shift Chlorin Absorptions and Enable Oxidative Chlorin Polymerizations
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2017 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 17, p. 4089-4095Article in journal (Refereed) Published
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.

Keywords
chlorins, electrochemistry, photophysics, polymerization, porphyrinoids
National Category
Organic Chemistry
Research subject
Chemistry with specialization in Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-317978 (URN)10.1002/chem.201604655 (DOI)000399312700011 ()27859811 (PubMedID)
Funder
Stiftelsen Olle Engkvist ByggmästareSwedish Research Council, 2013-4655Swedish Research Council, 2013-4763
Available from: 2017-03-22 Created: 2017-03-22 Last updated: 2017-12-28Bibliographically approved
Kovacs, D., Lu, X., Meszaros, L. S., Ott, M., Andres, J. & Borbas, K. E. (2017). Photophysics of Coumarin and Carbostyril-Sensitized Luminescent Lanthanide Complexes: Implications for Complex Design in Multiplex Detection. Journal of the American Chemical Society, 139(16), 5756-5767
Open this publication in new window or tab >>Photophysics of Coumarin and Carbostyril-Sensitized Luminescent Lanthanide Complexes: Implications for Complex Design in Multiplex Detection
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2017 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, no 16, p. 5756-5767Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Chemical Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-322722 (URN)10.1021/jacs.6b11274 (DOI)000400321500029 ()28388066 (PubMedID)
Funder
Swedish Research Council, 2013-4655Stiftelsen Olle Engkvist Byggmästare
Available from: 2017-05-29 Created: 2017-05-29 Last updated: 2019-04-16Bibliographically approved
Bornhof, A.-B., Xiong, R. & Borbas, K. E. (2017). Rational Synthesis of 2-Bromoporphyrins and 2,12-Dibromoporphyrins. Journal of Organic Chemistry, 82(23), 12908-12913
Open this publication in new window or tab >>Rational Synthesis of 2-Bromoporphyrins and 2,12-Dibromoporphyrins
2017 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 82, no 23, p. 12908-12913Article in journal (Refereed) Published
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.

National Category
Organic Chemistry
Identifiers
urn:nbn:se:uu:diva-343907 (URN)10.1021/acs.joc.7b02404 (DOI)000417342300100 ()
Funder
Swedish Research Council, 2013-4655
Available from: 2018-03-02 Created: 2018-03-02 Last updated: 2018-03-08Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2449-102x

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