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https://www.readbyqxmd.com/read/28102678/a-self-assembled-cofacial-cobalt-porphyrin-prism-for-oxygen-reduction-catalysis
#1
Amanda N Oldacre, Alan E Friedman, Timothy R Cook
Herein we report the first study of the oxygen reduction reaction (ORR) catalyzed by a cofacial porphyrin scaffold accessed in high yield (overall 53%) using coordination-driven self-assembly with no chromatographic purification steps. The ORR activity was investigated using chemical and electrochemical techniques on monomeric cobalt(II) tetra(meso-4-pyridyl)porphyrinate (CoTPyP) and its cofacial analogue [Ru8(η(6)-iPrC6H4Me)8(dhbq)4(CoTPyP)2][OTf]8 (Co Prism) (dhbq = 2,5-dihydroxy-1,4-benzoquinato, OTf = triflate) as homogeneous oxygen reduction catalysts...
January 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28102393/chemically-reversible-binding-of-h2s-to-a-zinc-porphyrin-complex-towards-implementation-of-a-reversible-sensor-via-a-coordinative-based-approach
#2
Maria Strianese, Marina Lamberti, Claudio Pellecchia
Binding of hydrogen sulfide (H2S) to a zinc porphyrin complex and the stabilization of the related zinc hydrosulfido adduct are explored. High-resolution MALDI Fourier transform ion cyclotron resonance mass spectrometry (HR MALDI-FT-ICR) and (1)H NMR experiments provide evidence that HS(-) coordination occurs at the zinc centre. The coordination of HS(-) occurs in a reversible manner and modulates fluorescence emission of a tetra(N-methylpyridyl)porphine zinc complex (TMPyPZn). The results highlight the potential of TMPyPZn and related systems for the implementation of fast and simple H2S sensors via a coordinative-based approach...
January 19, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28098314/isoindoline-nitroxide-labeled-porphyrins-as-potential-fluorescence-suppressed-spin-probes
#3
F Liu, T J Zou, Z L Tan, S Chen, Z H Wu, G P Yan, Q Zhang, S C Liang, J Yang
A series of isoindoline nitroxide-labeled porphyrins were synthesized by the reaction of 5-phenyldipyrromethane and 5-(4'-carboethoxy-methyleneoxyphenyl)dipyrromethane with 5-formyl-1,1,3,3-tetramethylisoindolin-2-yloxyl (FTMIO) using the Lindsey method. The corresponding water-soluble spin-labeled porphyrins were also prepared. Subsequently, these compounds were characterized and their in vitro properties were evaluated. The electrochemical assay demonstrated that these isoindoline nitroxide-labeled porphyrins had similar electrochemical and redox properties to 5-carboxy-1,1,3,3-tetramethylisoindolin-2-yloxyl (CTMIO)...
January 18, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28098289/photoactive-meso-tetra-4-pyridyl-porphyrin-tetrakis-chloro-2-2-bipyridine-platinum-ii-derivatives-recognize-and-cleave-dna-upon-irradiation
#4
Vanessa A Oliveira, Bernardo A Iglesias, Bruna L Auras, Ademir Neves, Hernán Terenzi
In this work, we evaluate the interaction of the peripheral Pt(bpy)Cl(+) substituted porphyrins, H2PtPor and ZnPtPor with DNA using UV-vis, emission fluorescence, CD spectroscopy, and DNA melting properties altered by the Pt(ii)-porphyrinoid compounds. Additionally, we observe the ability of these porphyrin derivatives to generate (1)O2 and to efficiently photocleave plasmid DNA upon visible light irradiation based on a mixed (oxidative/hydrolytic) mechanism.
January 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28097055/comprehensive-transcriptome-analysis-provides-new-insights-into-nutritional-strategies-and-phylogenetic-relationships-of-chrysophytes
#5
Daniela Beisser, Nadine Graupner, Christina Bock, Sabina Wodniok, Lars Grossmann, Matthijs Vos, Bernd Sures, Sven Rahmann, Jens Boenigk
BACKGROUND: Chrysophytes are protist model species in ecology and ecophysiology and important grazers of bacteria-sized microorganisms and primary producers. However, they have not yet been investigated in detail at the molecular level, and no genomic and only little transcriptomic information is available. Chrysophytes exhibit different trophic modes: while phototrophic chrysophytes perform only photosynthesis, mixotrophs can gain carbon from bacterial food as well as from photosynthesis, and heterotrophs solely feed on bacteria-sized microorganisms...
2017: PeerJ
https://www.readbyqxmd.com/read/28092824/chemically-modified-amino-porphyrin-tio2-for-the-degradation-of-acid-black-1-under-day-light-illumination
#6
Balu Krishnakumar, Avula Balakrishna, Cláudia T Arranja, Carlos M F Dias, Abilio J F N Sobral
In this paper, for the first time, chemically modified 5,10,15,20-meso-tetra-(para-amino)-phenyl-porphyrin/TiO2 (TPAPP/TiO2) was prepared and used for the degradation of an azo dye Acid Black 1 (AB 1) under direct sunlight. Initially, TiO2 was prepared by sol-gel method. Before making a TPAPP/TiO2 composite, the surface modification of TiO2 was carried out with glycidoxypropyltrimethoxy silane (GPTMS) which acts as a coupling agent. This is an epoxy terminated silane and could easily bond to the amino group of TPAPP through epoxy cleavage...
January 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28091783/lifetime-based-oxygen-sensing-properties-of-palladium-ii-and-platinum-ii-meso-tetrakis-4-phenylethynyl-phenylporphyrin
#7
Emel Önal, Stephan Saß, Jeanne Hurpin, Kadriye Ertekin, Sevinc Zehra Topal, Michael U Kumke, Catherine Hirel
High oxygen permeable [poly(TMSP)] nanofibers incorporating porphyrin macrocycle as luminescence indicators were prepared by electrospinning technique. The porphyrins involves were modified by i) introducing phenylacetylide substituents on the para position of the phenyl moieties and ii) varying the metal centers [Pt(II) or Pd(II)] of the meso-tetrakisphenylporphyrins. A set of nanofibers; (Pt-TPP)NF, (Pd-TPP)NF, (Pt-TPA)NF and (Pd-TPA)NF were obtained to study their structure-activity relationship toward oxygen...
January 14, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28091638/highly-ordered-sandwich-type-phthalocyaninato-porphyrinato-europium-double-decker-nanotubes-and-room-temperature-no2-sensitive-properties
#8
Peihua Zhu, Yucheng Wang, Pan Ma, Feifei Song, Xinyu Han, Shuncheng Yao, Cheng Yang
A sandwich-type (phthalocyaninato)(porphyrinato) europium double-decker complex Eu(TPyP){Pc-(OC8H17)8} [TPyP = meso-tetra(4-pyridyl)porphyrin; Pc-(OC8H17)8 = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyanine] (2) was designed and prepared. For comparative studies, Eu(TPyP)(Pc) (1) was also prepared. Highly ordered nanotubes of complexes 1 and 2 were successfully fabricated by using an anodized alumina oxide (AAO) template method. The nanotubes were comparatively investigated by electronic absorption spectra, scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS) techniques...
January 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28081363/distance-dependent-measurements-of-the-conductance-of-porphyrin-nanorods-studied-with-conductive-probe-atomic-force-microscopy
#9
Xianglin Zhai, Denzel Alexander, Pedro Derosa, Jayne C Garno
Protocols for nanopatterning porphyrins on Au(111) were developed based on immersion particle lithography. Porphyrins with and without a central metal ion, 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin cobalt(II) (CoTPP) were selected for study, which spontaneously formed nanorod geometries depending on concentration parameters. The elongated shapes of the nanorods offers an opportunity for successive distance-dependent conductive probe-atomic force microscopy (CP-AFM) measurements along the length of the nanorods...
January 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28080030/chemoselective-enzymatic-c-h-bond-amination-catalyzed-by-a-cytochrome-p450-containing-an-ir-me-pix-cofactor
#10
Pawel Dydio, Hanna M Key, Hiroki Hayashi, Douglas S Clark, John F Hartwig
Cytochrome P450 enzymes have been engineered to catalyze abiological C-H bond amination reactions, but this abiological process is limited by the low chemoselectivity for the amination of C-H bonds over competing reduction of the substrate to a sulfonamide. Here we report that P450s derived from a thermophilic organism and containing an iridium porphyrin cofactor (Ir(Me)-PIX) in place of the heme catalyze C-H bond amination reactions with high chemoselectivity for intramolecular insertion of the resulting nitrenes into C-H bonds over reduction of the azide to the sulfonamide and with broader substrate scope than that of enzymes containing iron porphyrins...
January 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28079223/ultrafast-energy-and-electron-transfers-in-structurally-well-addressable-bodipy-porphyrin-fullerene-polyads
#11
Di Gao, Shawkat M Aly, Paul-Ludovic Karsenti, Gessie Brisard, Pierre D Harvey
Two electron transfer polyads built upon [C60]-[ZnP]-[BODIPY] (1) and [ZnP]-[ZnP](-[BODIPY])(-[C60]) (2), where [C60] = N-methyl-2-phenyl-3,4-fulleropyrrolidine, [BODIPY] = boron dipyrromethane, and [ZnP] = zinc(ii) porphyrin, were synthesized along with their corresponding energy transfer polyads [ZnP]-[BODIPY] (1a) and [ZnP]-[ZnP]-[BODIPY] (2a) as well as relevant models. These polyads were studied using cyclic voltammetry, DFT computations, steady state and time-resolved fluorescence spectroscopy, and fs transient absorption spectroscopy...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28068469/porphyrin-based-porous-organic-frameworks-as-a-biomimetic-catalyst-for-highly-efficient-colorimetric-immunoassay
#12
Xiao Deng, Yishan Fang, Sha Lin, Qian Cheng, Qingyun Liu, Xiaomei Zhang
Herein, we synthesized a cost-effective iron porphyrin (FePor)-based covalent organic polymer (COP), FePor-TFPA-COP, through an easy aromatic substitution reaction between pyrrole and tris(4-formylphenyl)amine (TFPA). The triangular pyramid-shaped, N-centric structure of TFPA facilitated the formation of FePor-TFPA-COP with three-dimensional porous structure, larger surface area, and abundant surface catalytically active sites. FePor-TFPA-COP exhibited strong intrinsic peroxidase activity toward a classical peroxidase substrate, 3,3',5,5'-tetramethylbenzidine (TMB), in the presence of H2O2...
January 18, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28065861/targeting-and-modulating-infarct-macrophages-with-hemin-formulated-in-designed-lipid-based-particles-improves-cardiac-remodeling-and-function
#13
Tamar Ben-Mordechai, David Kain, Radka Holbova, Natalie Landa, La-Paz Levin, Inbar Elron-Gross, Yifat Glucksam-Galnoy, Micha S Feinberg, Rimona Margalit, Jonathan Leor
Uncontrolled activation of pro-inflammatory macrophages after myocardial infarction (MI) accelerates adverse left ventricular (LV) remodeling and dysfunction. Hemin, an iron-containing porphyrin, activates heme oxygenase-1 (HO-1), an enzyme with anti-inflammatory and cytoprotective properties. We sought to determine the effects of hemin formulated in a macrophage-targeted lipid-based carrier (denoted HA-LP) on LV remodeling and function after MI. Hemin encapsulation efficiency was ~100% at therapeutic dose levels...
January 5, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28059500/control-and-monitoring-of-dye-distribution-in-mesoporous-tio2-film-for-improving-photovoltaic-performance
#14
Byung-Man Kim, Hyun-Gyu Han, Jeong Soo Kim, HyeonOh Shin, Tae-Hyuk Kwon
Dye distribution in a mesoporous TiO2 film is a key factor in the performance of dye-sensitized solar cells, but there has been little research on it. Here we report even dye distribution within the porous TiO2 film achieved by a physical driving force of gas flow. Gas-assisted dye arrangement, gas bubbling soaking (GBS), significantly accelerates the dye infiltration compared to conventional overnight soaking (OS). As a demonstration, we investigated the time-dependent dye infiltration using plasmon sensors...
January 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28059428/photochemical-behavior-of-biosupramolecular-assemblies-of-photosensitizers-cucurbit-n-urils-and-albumins
#15
Javiera Cáceres, José Robinson-Duggon, Anita Tapia, Constanza Paiva, Matías Gómez, Cornelia Bohne, Denis Fuentealba
Biosupramolecular assemblies combining cucurbit[n]urils (CB[n]s) and proteins for the targeted delivery of drugs have the potential to improve the photoactivity of photosensitizers used in the photodynamic therapy of cancer. Understanding the complexity of these systems and how it affects the properties of photosensitizers is the focus of this work. We used acridine orange (AO(+)) as a model photosensitizer and compared it with methylene blue (MB(+)) and a cationic porphyrin (TMPyP(4+)). Encapsulation of the photosensitizers into CB[n]s (n = 7, 8) modified their photoactivity...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28059409/in-vivo-photoacoustic-tumor-tomography-using-a-quinoline-annulated-porphyrin-as-nir-molecular-contrast-agent
#16
Michael Luciano, Mohsen Erfanzadeh, Feifei Zhou, Hua Zhu, Tobias Bornhütter, Beate Röder, Quing Zhu, Christian Brückner
The synthesis and photophysical properties of a tetra-PEG-modified and freely water-soluble quinoline-annulated porphyrin are described. We previously demonstrated the ability of quinoline-annulated porphyrins to act as an in vitro NIR photoacoustic imaging (PAI) contrast agent. The solubility of the quinoline-annulated porphyrin derivative in serum now allowed the assessment of the efficacy of the PEGylated derivative as an in vivo NIR contrast agent for the PAI of an implanted tumor in a mouse model. A multi-fold contrast enhancement when compared to the benchmark dye ICG could be shown, a finding that could be traced to its photophysical properties (short triplet lifetimes, low fluorescence and singlet oxygen sensitization quantum yields)...
January 6, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28058285/large-hyperpolarizabilities-at-telecommunication-relevant-wavelengths-in-donor-acceptor-donor-nonlinear-optical-chromophores
#17
Animesh Nayak, Jaehong Park, Kurt De Mey, Xiangqian Hu, Timothy V Duncan, David N Beratan, Koen Clays, Michael J Therien
Octopolar D2-symmetric chromophores, based on the MPZnM supermolecular motif in which (porphinato)zinc(II) (PZn) and ruthenium(II) polypyridyl (M) structural units are connected via ethyne linkages, were synthesized. These structures take advantage of electron-rich meso-arylporphyrin or electron-poor meso-(perfluoroalkyl)porphyrin macrocycles, unsubstituted terpyridyl and 4'-pyrrolidinyl-2,2';6',2″-terpyridyl ligands, and modulation of metal(II) polypyridyl-to-(porphinato)zinc connectivity, to probe how electronic and geometric factors impact the measured hyperpolarizability...
December 28, 2016: ACS Central Science
https://www.readbyqxmd.com/read/28054784/porphyrin-polyyne-3-and-5-rotaxanes
#18
Daniel R Kohn, Levon D Movsisyan, Amber L Thompson, Harry L Anderson
Porphyrin-polyyne [3]- and [5]rotaxanes have been synthesized by condensing aldehyde-rotaxanes with pyrrole or dipyrromethane. The crystal structure of a [3]rotaxane shows that the macrocycles adopt compact conformations, holding the hexaynes near the porphyrin core, and that the phenanthroline units form intermolecular π-stacked dimers in the solid. Fluorescence spectra reveal singlet excited-state energy transfer from the threaded hexayne to the porphyrin, from the phenanthroline to the porphyrin, and from the phenanthroline to the hexayne...
January 5, 2017: Organic Letters
https://www.readbyqxmd.com/read/28054781/reversible-vesicle-to-disk-transitions-of-liposomes-induced-by-the-self-assembly-of-water-soluble-porphyrins
#19
Kouta Sugikawa, Yutaro Takamatsu, Kazuma Yasuhara, Masafumi Ueda, Atsushi Ikeda
Structural control of lipid membranes is important for mechanisms underlying biological functions and for creating high-functionality soft materials. We demonstrate the reversible control of vesicle structures (liposomes) using supramolecular assemblies. Specifically, water-soluble anionic porphyrin molecules interact with positively charged lipid membrane surfaces to form one-dimensional self-assembled structures (J-aggregates) under acidic conditions. Cryogenic transmission electron microscopy revealed that porphyrin J-aggregates on the membrane surface induced an extensive structural change from vesicles to layered disks...
January 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28054076/push-pull-pyropheophorbides-for-nonlinear-optical-imaging
#20
Anjul Khadria, Yovan de Coene, Przemyslaw Gawel, Cécile Roche, Koen Clays, Harry L Anderson
Pyropheophorbide-a methyl ester (PPa-OMe) has been modified by attaching electron-donor and -acceptor groups to alter its linear and nonlinear optical properties. Regioselective bromination of the terminal vinyl position and Suzuki coupling were used to attach a 4-(N,N-diethylaminophenyl) electron-donor group. The electron-acceptor dicyanomethylene was attached at the cyclic ketone position through a Knoevenagel condensation. Four different derivatives of PPa-OMe, containing either electron-donor or electron-acceptor groups, or both, were converted to hydrophilic bis-TEG amides to generate a series of amphiphilic dyes...
January 5, 2017: Organic & Biomolecular Chemistry
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