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  • 1.
    Carlsson, Marcus
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Desroches, Cedric
    Lindgren, Mikael
    Lopes, Cesar
    Parola, Stephane
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Chemistry.
    Synthesis of di(arylethynyl)bis(tributylphosphine) platinum(II) complexes and preparation of organic-inorganic hybrid silica glass for nonlinear absorption of lightManuscript (preprint) (Other (popular science, discussion, etc.))
  • 2.
    Carlsson, Marcus
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Chemistry.
    One-pot synthesis of trans mono- or diarylalkynyl substituted platinum(II) compounds with tertiary phosphine or phosphite ligands2006In: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 25, no 22, p. 5500-5502Article in journal (Refereed)
    Abstract [en]

    An efficient one-pot synthesis has been developed for preparation of trans-mono- or diarylalkynyl bisphosphine or bisphosphite Pt(II) compounds. In the procedure, the alkyne and the tertiary phosphorus ligands are mixed with PtCl2 in tetrahydrofuran and triethylamine solution. CuI is added for synthesis of disubstituted complexes, but the catalyst is not used for preparation of monosubstituted complexes. Microwave irradiation is preferably employed to give the trans-mono- or diarylalkynyl Pt(II) compound in short time and high yield.

  • 3. Glimsdal, Eirik
    et al.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Chemistry.
    Minaev, Boris
    Lindgren, Mikael
    Excited States and Two-Photon Absorption of Some Novel Thiophenyl Pt(II)-Ethynyl Derivatives2007In: JOURNAL OF PHYSICAL CHEMISTRY A, Vol. 111, p. 244-50Article in journal (Refereed)
    Abstract [en]

    The photophysical characterization of two new compounds related to bis((4-(phenylethynyl)phenyl)ethynyl)bis(tributylphosphine)platinum(II), here abbreviated Pt1, is reported. For the first new compound ATP1, the inner phenyl rings (closer to the Pt atom) in Pt1 are replaced by thiophene rings bridging at the 2,5-positions. In compound ATP2, the outer phenyl groups are replaced by thiophene rings bonded at the 2-position. Specifically, we report on the fluorescence quantum yield, two-photon absorption, triplet decay times and two-photon absorption induced emission spectra of the molecules in THF solutions. The results were compared with those of Pt1 and Pt1 capped with an acetonide-protected 2,2-bis(methylol)propionic acid (bis-MPA) ester group (Pt1-G1). The photophysical properties of the organic dye 7-(diethylamino)coumarin (Coumarin 110) were determined and used as a reference material. The two-photon absorption cross section around 720-740 nm of ATP1 and ATP2 was found to be of the same order of magnitude as for Pt1-G1, i.e., between 5 and 10 GM, but slightly larger for ATP1 than for ATP2 (1 GM = 1 Goppert-Mayer = 10(-50) (cm(4) s)/photon). The fluorescence decay time of all compounds was found to be very short (subnanosecond) with quantum yields 0.0045, 0.0007, 0.0011 and 0.0020 for ATP1, ATP2, Pt1-G1 and Pt1, respectively, measured at excitation wavelength 373 nm. Just as Pt1 and Pt1-G1, both thiophenyl derivatives showed large intersystem crossing capabilities and phosphorescence, characteristic for a triplet state that can enhance the nonlinear absorption and optical power limiting by triplet state absorption. The phosphorescence emission of the thiophenyl derivatives was red-shifted in comparison with Pt1 and Pt1-G1, and the phosphorescence decay times were on the order of 200-500 ns, as for the Pt1 compound.

  • 4.
    Glimsdal, Eirik
    et al.
    Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kindahl, Tomas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lindgren, Mikael
    Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
    Lopes, Cesar
    Division of Information Systems, Swedish Defence Research Agency (FOI), Linköping, Sweden.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Luminescence, singlet oxygen production, and optical power limiting of some diacetylide platinum(II) diphosphine complexes2010In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 114, no 10, p. 3431-3442Article in journal (Refereed)
    Abstract [en]

    A series of four new trans-diphosphine Pt(II) diacetylide complexes, with a thiophene and two benzenoid rings in each acetylide ligand, have been synthesized and characterized with respect to optical absorption, spectrally and time-resolved luminescence, and optically nonlinear properties such as two-photon absorption cross section and optical power limiting. Density functional theory (DFT) calculations of a few ground state conformations of three Pt(II) diacetylide structures showed similar total energy for each geometry-optimized rotamer but some differences in the vertical excitation energies and in the ligand-to-metal charge-transfer character. The wavelengths of the calculated excitations were found to be red-shifted compared with peaks in the optical absorption spectra, but the general trends and shifts of wavelengths between the different structures are well reproduced. Static emission spectra for degassed samples in THF solution of the larger compounds showed small Stokes shifts and low fluorescence quantum yields, indicating fast intersystem crossing to the triplet manifold. More pronounced differences between the compounds were displayed in the phosphorescence data, in terms of spectral emission wavelengths and decay times. For instance, the phosphorescence decay of the compound with the thiophene ring close to the Pt center was found to be significantly faster than for the other compounds. A possible relationship between triplet lifetime and conformation of the compounds is discussed. It was also demonstrated that the quenching of the excited triplet states in air-saturated samples involves energy transfer to the oxygen triplet state, and subsequent generation of singlet oxygen showing the typical emission at approximately 1275 nm. The amount of produced singlet oxygen followed the phosphorescence yields of the solute molecules. Two-photon absorption cross sections (sigma(2)) were measured and showed values on the order of 10 GM at 780 nm for all compounds. Optical power limiting measurements of the new complexes in THF using 5 ns pulses, showed only slightly better performance at the wavelength of 532 nm compared to that of similar platinum compounds with only two aryl rings in each ligand. At 600 nm the complexes with three aryl rings were significantly better optical limiters than the smaller compounds with two aryl rings in the ligands.

  • 5.
    Glimsdal, Eirik
    et al.
    Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
    Dragland, Ingunn
    Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Melø, Thor Bernt
    Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
    Lindgren, Mikael
    Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
    Triplet excited states of some thiophene and triazole substituted platinum(II) acetylide chromophores2009In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 113, no 14, p. 3311-3320Article in journal (Refereed)
    Abstract [en]

    The photophysical properties of a series of platinum(II) acetylide compounds (trans-Pt(PBu(3))(2)(CC-R)(2)) with the R group consisting of two or three aryl rings (phenyl, phenyl/thiophenyl, phenyl/triazolyl) linked together with ethynyl groups were systematically investigated. Four new structurally similar compounds are reported with: (i) a bithiophene unit in the ligands, (ii) methyl or (iii) methoxy substituents on the aryl ring ligands that promote a more twisted conformation along the long axis of the molecule, and (iv) with two different alkynylaryl ligands giving rise to an asymmetric substitution with respect to the photoactive metal ion center. The spectroscopic studies include optical absorption, spectrally and time-resolved luminescence, as well as transient absorption spectra. The ground-state UV absorption between 300 and 420 nm gave rise to fluorescence with quantum efficiencies in the range of 0.1-1% and efficient intersystem crossing to triplet states. Phosphorescence decay times were in the order of 10-500 mus in oxygen-evacuated samples. The triplet states also lead to strong broadband triplet-triplet absorption between 400 and 800 nm. The complex with asymmetric substitution was found to populate two triplet states of different structure and energy.

  • 6.
    Keefover-Ring, Ken
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Albrectsen, Benedicte R
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    2 '-(Z)-Cinnamoylsalicortin: A novel salicinoid isolated from Populus tremula2014In: Phytochemistry Letters, ISSN 1874-3900, E-ISSN 1876-7486, Vol. 7, p. 212-216Article in journal (Refereed)
    Abstract [en]

    Using a combination of NMR and mass spectroscopic techniques, we have isolated a new salicinoid from the foliage of European aspen (Populus tremula) and identified it as 2'-(Z)-cinnamoylsalicortin. The relatively high amounts in foliage and the similarity in structure to bioactive salicinoids isolated from other salicaceous trees indicates that this compound may have implications for the study of P. tremulaherbivore interactions.

  • 7.
    Lind, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Eriksson, Anders
    Glimsdal, Eirik
    Lindgren, Mikael
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Structural, photophysical, and nonlinear absorption properties of trans-di-arylalkynyl Platinum(II) Complexes with Phenyl and Thiophenyl Groups2007In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 111, no 9, p. 1598-1609Article in journal (Refereed)
    Abstract [en]

    Optical power limiting and luminescence properties of two Pt(II) complexes with thiophenyl and phenyl groups in the ligands, trans-Pt(P(n-Bu)3)2(C[triple bond]C-Ar)2, where Ar = -C4H2S-C[triple bond]C-p-C6H4-n-C5H11 (1) and -p-C6H4-C[triple bond]C-C4H3S (2), have been investigated. The fluorescence lifetimes were found to be on the sub-nanosecond time scale, and the quantum yields were low, in accord with fast intersystem crossing from the excited singlet to triplet manifold. The phosphorescence lifetimes of 1 and 2 were shorter than that of a Pt(II) complex having two phenyl groups in the ligands. In order to elucidate the C-Pt bonding nature in the ground state, the 13C NMR chemical shift of the carbon directly bonded to Pt, the coupling constants 1JPtC, 2JPtC, and 1JPtP, and IR νC[triple bond]C wavenumbers were obtained for 1, 2, and three other trans-diarylalkynyl Pt(II) complexes. X-ray diffraction data of 1 and 2 and density functional theory calculated geometries of models of 1, 2, and trans-Pt(P(n-Bu)3)2(C[triple bond]C-p-C6H4-C[triple bond]C-C6H5)2 (3) show that 1 preferably exists in a different conformation from that of 2 and 3. The variations in photophysical, NMR, and IR data can be rationalized by differences in geometry and pi-backbonding from Pt to the alkynyl ligand.

  • 8.
    Nilsson, Lina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Larsson, Andreas
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Swedish Defence Research Agency, CBRN Defence and Security.
    Begum, Afshan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Iakovleva, Irina
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kristoffer, Brännström
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Sauer-Eriksson, Elisabeth
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Olofsson, Anders
    Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
    Modifications of the 7-Hydroxyl Group of the Transthyretin Ligand Luteolin Provide Mechanistic Insights into Its Binding Properties and High Plasma Specificity2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 4, article id e0153112Article in journal (Refereed)
    Abstract [en]

    Amyloid formation of the plasma protein transthyretin (TTR) has been linked to familial amyloid polyneuropathy and senile systemic amyloidosis. Binding of ligands within its natural hormone binding site can stabilize the tetrameric structure and impair amyloid formation. We have recently shown that the flavonoid luteolin stabilizes TTR in human plasma with a very high selectivity. Luteolin, however, is inactivated in vivo via glucuronidation for which the preferred site is the hydroxy group at position 7 on its aromatic A-ring. We have evaluated the properties of two luteolin variants in which the 7-hydroxy group has been exchanged for a chlorine (7-Cl-Lut) or a methoxy group (7-MeO-Lut). Using an in vitro model, based on human liver microsomes, we verified that these modifications increase the persistence of the drug. Crystal structure determinations show that 7-Cl-Lut binds similarly to luteolin. The larger MeO substituent cannot be accommodated within the same space as the chlorine or hydroxy group and as a result 7-MeO-Lut binds in the opposite direction with the methoxy group in position 7 facing the solvent. Both 7-Cl-Lut and 7-MeO-Lut qualify as high-affinity binders, but in contrast to luteolin, they display a highly non-specific binding to other plasma components. The binding of the two conformations and the key-interactions to TTR are discussed in detail. Taken together, these results show a proof-of-concept that the persistence of luteolin towards enzymatic modification can be increased. We reveal two alternative high-affinity binding modes of luteolin to TTR and that modification in position 7 is restricted only to small substituents if the original orientation of luteolin should be preserved. In addition, the present work provides a general and convenient method to evaluate the efficacy of TTR-stabilizing drugs under conditions similar to an in vivo environment.

  • 9.
    Strand, Mårten
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Uvell, Hanna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Islam, Koushikul
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Edlund, Karin
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Cullman, Inger
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Altermark, Björn
    Mei, Ya-Fang
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Elofsson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Willassen, Nils-Peder
    Wadell, Göran
    Umeå University, Faculty of Medicine, Department of Clinical Microbiology, Virology.
    Almqvist, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Isolation and characterization of anti-adenoviral secondary metabolites from marine actinobacteria2014In: Marine Drugs, ISSN 1660-3397, E-ISSN 1660-3397, Vol. 12, no 2, p. 799-821Article in journal (Refereed)
    Abstract [en]

    Adenovirus infections in immunocompromised patients are associated with high mortality rates. Currently, there are no effective anti-adenoviral therapies available. It is well known that actinobacteria can produce secondary metabolites that are attractive in drug discovery due to their structural diversity and their evolved interaction with biomolecules. Here, we have established an extract library derived from actinobacteria isolated from Vestfjorden, Norway, and performed a screening campaign to discover anti-adenoviral compounds. One extract with anti-adenoviral activity was found to contain a diastereomeric 1:1 mixture of the butenolide secondary alcohols 1a and 1b. By further cultivation and analysis, we could isolate 1a and 1b in different diastereomeric ratio. In addition, three more anti-adenoviral butenolides 2, 3 and 4 with differences in their side-chains were isolated. In this study, the anti-adenoviral activity of these compounds was characterized and substantial differences in the cytotoxic potential between the butenolide analogs were observed. The most potent butenolide analog 3 displayed an EC50 value of 91 μM and no prominent cytotoxicity at 2 mM. Furthermore, we propose a biosynthetic pathway for these compounds based on their relative time of appearance and structure.

  • 10. Vestberg, Robert
    et al.
    Westlund, Robert
    Eriksson, Anders
    Lopes, Cesar
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Chemistry.
    Glimsdal, Eirik
    Lindgren, Mikael
    Malmström, Eva
    Dendron Decorated Platinum(II) Acetylides for Optical Power Limiting2006In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 39, no 6, p. 2238-2246Article in journal (Refereed)
    Abstract [en]

    The effect of dendritic substituents on a nonlinear optical chromophore for optical power limiting (OPL) has been investigated. Synthesis and characterization of bis((4-(phenylethynyl)phenyl)ethynyl)bis(tributylphosphine)platinum(II) with dendritic end groups are described. Polyester dendrimers up to the fourth generation were grown divergently using the anhydride of 2,2-bis(methylol)propionic acid (bis-MPA). The introduction of the dendritic moieties onto the NLO chromophore enables further processing of the materials using polymeric and related techniques. OPL measurements performed at 532, 580, and 630 nm show that the OPL properties improve with increasing size of the dendritic substituent. It is also shown that the addition of the dendrons increase the OPL as compared to the nondecorated bis((4-(phenylethynyl)phenyl)ethynyl)bis(tributylphosphine)platinum(II). By use of femtosecond z-scan measurements carried out at different pulse-repetition frequencies, it is shown that the two-photon absorption cross section is ~10 GM. Using pulse repetition frequencies (100 kHz-4.75 MHz) so that the time between the pulses is comparable with the triplet excited lifetime, the z-scans become dominated by excited-state absorption of excited triplet states.

  • 11.
    Zieba, Roman
    et al.
    Laboratoire des Multimatériaux et Interfaces CNRS 5615 University Claude Bernard Lyon 1 University of Lyon, Villeurbanne, France.
    Desroches, Cédric
    Laboratoire des Multimatériaux et Interfaces CNRS 5615 University Claude Bernard Lyon 1 University of Lyon, Villeurbanne, France.
    Chaput, Frédéric
    Laboratoire des Multimatériaux et Interfaces CNRS 5615 University Claude Bernard Lyon 1 University of Lyon, Villeurbanne, France.
    Carlsson, Marcus
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Eliasson, Bertil
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lopes, Cesar
    Dep. of Optronic Systems Swedish Defence Research Agency (FOI) Linköping, Sweden.
    Lindgren, Mikael
    Department of Physics Norwegian University of Science and Technology Trondheim, Norway.
    Parola, Stephane
    Laboratoire des Multimatériaux et Interfaces CNRS 5615 University Claude Bernard Lyon 1 University of Lyon, Villeurbanne, France.
    Preparation of functional hybrid glass material from Platinum (II) Complexes for broadband nonlinear absorption of light2009In: Advanced Funcitional Materials, Vol. 19, no 2, p. 235-241Article in journal (Refereed)
    Abstract [en]

    The synthesis of trans-di(arylalkynyl)diphosphine platinum(II) complexes bearing trialkoxysilane groups is described, as well as the preparation of siloxane-based hybrid materials from organometallic chromophores through a modified sol-gel process. Glass materials prepared from trans-[P(n-Bu)3]2Pt[(CC-p-C6H4-CC-p-C6H4-CH2O(CO)NH(CH2)3Si(OC2H5)3]2 generally show spectral transmittance, absorption and luminescence similar to that of solutions reported in the literature. Measurements of optical power limiting for the hybrid glass are carried out, and show broadband nonlinear absorption throughout the whole visible wavelength range with clamping values in the range 0.2-7 µJ at 120 mM chromophore concentration. The sol-gel process using urethane-propyltriethoxysilane-functionalized chromophores as precursors appears to be a valid method for formation of robust silicate materials with grafted diarylethynyl Pt(II) complexes for OPL devices.

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