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https://www.readbyqxmd.com/read/28430417/charge-separation-mechanisms-in-ordered-films-of-self-assembled-donor-acceptor-dyad-ribbons
#1
Jenna L Logsdon, Patrick E Hartnett, Jordan N Nelson, Michelle A Harris, Tobin J Marks, Michael R Wasielewski
Orthogonal attachment of polar and nonpolar side-chains to a zinc porphyrin-perylenediimide dyad (ZnP-PDI, 1a) is shown to result in self-assembly of ordered supramolecular ribbons in which the ZnP and PDI molecules form segregated π-stacked columns. Following photoexcitation of the ordered ribbons, ZnP(+•)-PDI(-•) radical ion pairs form in <200 fs and subsequently produce a 30 ± 3% yield of free charge carriers that live for about 100 μs. Elongating the side chains on ZnP and PDI in 1b enhances the order of the films, but does not result in an increase in free charge carrier yield...
April 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28430199/control-over-differentiation-of-a-metastable-supramolecular-assembly-in-one-and-two-dimensions
#2
Tomoya Fukui, Shinnosuke Kawai, Satoko Fujinuma, Yoshitaka Matsushita, Takeshi Yasuda, Tsuneaki Sakurai, Shu Seki, Masayuki Takeuchi, Kazunori Sugiyasu
Molecular self-assembly under kinetic control is expected to yield nanostructures that are inaccessible through the spontaneous thermodynamic process. Moreover, time-dependent evolution, which is reminiscent of biomolecular systems, may occur under such out-of-equilibrium conditions, allowing the synthesis of supramolecular assemblies with enhanced complexities. Here we report on the capacity of a metastable porphyrin supramolecular assembly to differentiate into nanofibre and nanosheet structures. Mechanistic studies of the relationship between the molecular design and pathway complexity in the self-assembly unveiled the energy landscape that governs the unique kinetic behaviour...
May 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28429931/heterobimetallic-nitrido-complexes-of-group-8-metalloporphyrins
#3
Wai-Man Cheung, Wai-Hang Chiu, Matthew de Vere-Tucker, Herman H-Y Sung, Ian D Williams, Wa-Hung Leung
Heterobimetallic nitrido porphyrin complexes with the [(L)(por)M-N-M'(LOEt)Cl2] formula {por(2-) = 5,10,15,20-tetraphenylporphyrin (TPP(2-)) or 5,10,15,20-tetra(p-tolyl)porphyrin (TTP(2-)) dianion; LOEt(-) = [Co(η(5)-C5H5){P(O)(OEt)2}3](-); M = Fe, Ru, or Os; M' = Ru or Os; L = H2O or pyridine} have been synthesized, and their electrochemistry has been studied. Treatment of trans-[Fe(TPP)(py)2] (py = pyridine) with Ru(VI) nitride [Ru(LOEt)(N)Cl2] (1) afforded Fe/Ru μ-nitrido complex [(py)(TPP)Fe(μ-N)Ru(LOEt)Cl2] (2)...
April 21, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28426977/blue-violet-laser-inactivates-methicillin-resistant-staphylococcus-aureus-by-altering-its-transmembrane-potential
#4
Gabriel Biener, Daniela S Masson-Meyers, Violet V Bumah, Grant Hussey, Michael R Stoneman, Chukuka S Enwemeka, Valerica Raicu
The resistance of methicillin-resistant Staphylococcus aureus to antibiotics presents serious clinical problems that prompted the need for finding alternative or combination therapies. One such therapy is irradiation with blue light. To determine the alterations in metabolic processes implicated in the observed antimicrobial effects of blue light, we investigated the changes in membrane potential and the presence of free-radical-producing photo-acceptor molecules. Bacterial cultures irradiated with one or two doses of 405nm laser light (each consisting of 121J/cm(2)) were imaged with spectrally resolved laser-scanning microscopes to detect endogenous fluorescent species as well as the voltage sensitive dye 3,3'-Diethyloxacarbocyanine iodide...
April 6, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28425293/cosensitized-porphyrin-system-for-high-performance-solar-cells-with-tof-sims-analysis
#5
Wenjun Wu, Huaide Xiang, Wei Fan, Jinglin Wang, Haifeng Wang, Xin Hua, Zhaohui Wang, Yi-Tao Long, He Tian, Wei-Hong Zhu
Up to date, development of organic sensitizers has been predominately focused on light harvesting, HOMO and LUMO energy levels, and electron transferring process. In contrast, their adsorption mode as well as dynamic loading behaviour onto nanoporous TiO2 is rarely considered. Herein we have employed the time of flight secondary ion mass spectrometry (TOF-SIMS) to take insight into the competitive dye adsorption mode and kinetics in cosensitized porphyrin system. Using the novel porphyrin dye FW-1 and D-A-π-A featured dye WS-5, the different bond-breaking mode in TOF-SIMS and dynamic dye-loading amount during the coadsorption process are well compared with two different anchoring groups such as benzoic acid and cyanoacrylic acid...
April 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28424663/antimicrobial-photodynamic-therapy-against-endodontic-enterococcus-faecalis-and-candida-albicans-mono-and-mixed-biofilms-in-the-presence-of-photosensitizers-a-comparative-study-with-classical-endodontic-irrigants
#6
Patrícia Diogo, Chantal Fernandes, Francisco Caramelo, Marta Mota, Isabel M Miranda, M A F Faustino, M G P M S Neves, Marciana P Uliana, Kleber T de Oliveira, João M Santos, Teresa Gonçalves
Endodontic biofilms eradication from the infected root canal system remains as the primary focus in endodontic field. In this study, it was assessed the efficacy of antimicrobial Photodynamic Therapy (aPDT) with the Zn(II)chlorin e6 methyl ester (Zn(II)e6Me) activated by red light against monospecies and mixed biofilms of Enterococcus faecalis and Candida albicans. The results were compared with the ones obtained with Rose Bengal (RB), Toluidine Blue-O (TBO), the synthetic tetracationic porphyrin (TMPyP) as well as classical endodontic irrigants (3% NaOCl, 17% EDTA and 2% CHX)...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28422487/stepwise-deoxygenation-of-nitrite-as-a-route-to-two-families-of-ruthenium-corroles-group-8-periodic-trends-and-relativistic-effects
#7
Abraham B Alemayehu, Hugo Vazquez-Lima, Kevin J Gagnon, Abhik Ghosh
Given the many applications of ruthenium porphyrins, the rarity of ruthenium corroles and the underdeveloped state of their chemistry are clearly indicative of an area ripe for significant breakthroughs. The tendency of ruthenium corroles to form unreactive metal-metal-bonded dimers has been recognized as a key impediment in this area. Herein, by exposing free-base meso-tris(p-X-phenyl)corroles, H3[TpXPC] (X = CF3, H, Me, and OMe), and [Ru(COD)Cl2]x in refluxing 2-methoxyethanol to nitrite, we have been able to reliably intercept the series Ru[TpXPC](NO) in a matter of seconds to minutes and subsequently Ru(VI)[TpXPC](N), the products of a second deoxygenation, over some 16 h...
April 19, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28422333/assembling-porphyrins-into-extended-network-structures-employing-aromatic-dicarboxylates-synthesis-metal-exchange-and-heterogeneous-catalytic-studies
#8
Srinivasan Natarajan, Gargi Dutta, Ajay Kumar Jana
Three new metal-organic porphyrinic framework compounds of zinc and 5,10,15,20-tetrakis(4-pyridyl)porphyrin(TPyP) have been synthesized under solvothermal conditions. The compounds [Zn5(C40H24N8)(C8H4O4)2(NO3)6(DMA)2](DMA)3(H2O)8, 1; [Zn3(C40H24N8)(C8H4O4)2(DMF)](DMF)5(H2O)12, 2; and [Zn3(C40H24N8)(C12H6O4)2(DMA)2](H2O)7, 3 have two- (1) and three- dimensionally (2 and 3) extended structures. All the three structures contain porphyrinic unit connected through the carboxylate linkers. The nitrates binds the metal centers and not hydrogen bonded...
April 19, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28414447/supramolecular-porphyrin-photosensitizers-controllable-disguise-and-photoinduced-activation-of-antibacterial-behavior
#9
Linghui Chen, Haotian Bai, Jiang-Fei Xu, Shu Wang, Xi Zhang
A series of supramolecular photosensitizers were fabricated from porphyrin derivatives (Por) containing quaternary ammonium groups with cucurbit[7]uril (CB[7]) based on host-guest interactions. The antibacterial activity of Por in the dark could be turned off upon binding with CB[7], whereas the antibacterial activity under white-light illumination could be turned on. In addition, its antibacterial efficiency could be greatly enhanced by introducing metal ions. When Pd(II) was introduced into porphyrin, its antibacterial efficiency was enhanced from 40 to 100%...
April 17, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28414421/shape-controlled-metal-free-catalysts-facet-sensitive-catalytic-activity-induced-by-the-arrangement-pattern-of-noncovalent-supramolecular-chains
#10
Guangwei Geng, Penglei Chen, Bo Guan, Lang Jiang, Zhongfei Xu, Dawei Di, Zeyi Tu, Weichang Hao, Yuanping Yi, Chuncheng Chen, Minghua Liu, Wenping Hu
Metal-free catalytic materials have recently received broad attention as promising alternatives to metal-involved catalysts. This is owing to their inherent capability to overcome the inevitable limitations of metal-involved catalysts, such as high sensitivity to poisoning, the limited reserves, high cost and scarcity of metals (especially noble metals), etc. However, the lack of shape-controlled metal-free catalysts with well-defined facets is a formidable bottleneck limiting our understandings on the underlying structure-activity relationship at atomic/molecular level, which thereby restrains their rational design...
April 19, 2017: ACS Nano
https://www.readbyqxmd.com/read/28406618/microwave-mediated-synthesis-of-bulky-lanthanide-porphyrin-phthalocyanine-triple-deckers-electrochemical-and-magnetic-properties
#11
Hong-Guang Jin, Xiaoqin Jiang, Irina A Kühne, Sylvain Clair, Valérie Monnier, Christophe Chendo, Ghenadie Novitchi, Annie K Powell, Karl M Kadish, Teodor Silviu Balaban
Five heteroleptic lanthanide porphyrin-bis-phthalocyanine triple-decker complexes with bulky peripheral groups were prepared via microwave-assisted synthesis and characterized in terms of their spectroscopic, electrochemical, and magnetic properties. These compounds, which were easily obtained under our preparative conditions, would normally not be accessible in large quantities using conventional synthetic methods, as a result of the low yield resulting from steric congestion of bulky groups on the periphery of the phthalocyanine and porphyrin ligands...
April 13, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28406466/artificial-red-blood-cells-as-potential-photosensitizers-in-dye-laser-treatment-against-port-wine-stains
#12
REVIEW
Naoaki Rikihisa, Shoji Watanabe, Yoshiaki Saito, Hiromi Sakai
We suggest a novel method that uses artificial blood cells (hemoglobin vesicles, Hb-Vs) as photosensitizers in dye laser treatment (at 595-nm wavelength) for port-wine stains (i.e., capillary malformations presenting as red birthmarks) based on the results of animal experiments. As compared with human red blood cells, Hb-Vs have the same absorbance of 595 nm wavelength light and produce the same level of heat following dye laser irradiation. Small sized Hb-Vs (250 nm) distribute in the plasma phase in blood and tend to flow in the marginal zone of microvessels...
April 13, 2017: Journal of Functional Biomaterials
https://www.readbyqxmd.com/read/28402377/interrelationship-between-tio2-nanoparticle-size-and-kind-size-of-dyes-in-the-mechanism-and-conversion-efficiency-of-dye-sensitized-solar-cells
#13
Pooya Tahay, Meisam Babapour Gol Afshani, Ali Alavi, Zahra Parsa, Nasser Safari
In order to provide a comprehensive investigation of TiO2 nanoparticle size in relation with different dye types in DSSCs, three sizes of TiO2 nanoparticles and two different dye types including a porphyrin dye (T2) and a ruthenium dye (N3) were synthesized. Steady state current-voltage (J-V) characteristics were investigated for the fabricated DSSCs and the results demonstrated that the optimum TiO2 nanoparticle size changed with the dye type. The obtained J-V data were interpreted by cyclic voltammetry, UV-visible absorption spectroscopy, BET measurement, DFT calculation, IPCE measurement and impedance spectroscopy...
April 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28402012/a-stable-niii-porphyrin-meso-oxy-radical-with-a-quartet-ground-state
#14
Atsuhiro Osuka, Cosima Stähler, Daiki Shimizu, Kota Yoshida, Rainer Herges, Ko Furukawa
10,15-20-Tris(pentafluorophenyl)-substituted NiII-porphyrin meso-oxy radical bearing two coordinating pyridines was synthesized as a stable radical with a quartet ground state (S = 3/2). X-ray structural analysis has revealed that the NiII porphyrin moiety is fairly planar and the Ni-N bond lengths are considerably longer, indicating the high-spin state of the NiII center. The radical exhibited a quartet ground state, indicating the ferromagnetic interaction between the high-spin NiII center (S = 1) and the porphyrin meso-oxy radical (S = 1/2)...
April 12, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28401734/photoswitchable-sn-cyt-c-solid-state-devices
#15
Satoshi Nakamaru, Frank Scholz, William E Ford, Yoshio Goto, Florian von Wrochem
Electron transfer across proteins plays an important role in many biological processes, including those relevant for the conversion of solar photons to chemical energy. Previous studies demonstrated the generation of photocurrents upon light irradiation in a number of photoactive proteins, such as photosystem I or bacteriorhodopsin. Here, it is shown that Sn-cytochrome c layers act as reversible and efficient photoelectrochemical switches upon integration into large-area solid-state junctions. Photocurrents are observed both in the Soret band (λ = 405 nm) and in the Q band (λ = 535 nm), with current on/off ratios reaching values of up to 25...
April 12, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28398431/high-performance-thermoelectricity-in-edge-over-edge-zinc-porphyrin-molecular-wires
#16
Mohammed Noori, Hatef Sadeghi, Colin J Lambert
If high efficiency organic thermoelectric materials could be identified, then these would open the way to a range of energy harvesting technologies and Peltier coolers using flexible and transparent thin-film materials. We have compared the thermoelectric properties of three zinc porphyrin (ZnP) dimers and a ZnP monomer and found that the "edge-over-edge" dimer formed from stacked ZnP rings possesses a high electrical conductance, negligible phonon thermal conductance and a high Seebeck coefficient of the order of 300 μV K(-1)...
April 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/28398298/corrigendum-photothermal-therapeutic-application-of-gold-nanorods-porphyrin-trastuzumab-complexes-in-her2-positive-breast-cancer
#17
Xinmei Kang, Ximing Guo, Xingjian Niu, Weiwei An, Suhan Li, Zhaoliang Liu, Yue Yang, Na Wang, Qicheng Jiang, Caichuan Yan, Hui Wang, Qingyuan Zhang
No abstract text is available yet for this article.
April 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28397373/diphenylphosphine-oxide-fused-and-diphenylphosphine-fused-porphyrins-synthesis-tunable-electronic-properties-and-formation-of-cofacial-dimers
#18
Atsuhiro Osuka, Keisuke Fujimoto, Yuko Kasuga, Norihito Fukui
Diphenylphosphine-oxide-fused NiII porphyrin 8 was synthesized from 3,5,7-trichloroporphyrin 5 via a reaction sequence of nucleophilic aromatic substitution with lithium diphenylphosphide, oxidation with H2O2, and palladium-catalyzed intramolecular cyclization. Reduction of 8 with HSiCl3 gave diphenylphosphine-fused NiII porphyrin 9. The embedded P=O and P moieties serve as a strong electron-accepting and electron-donating group to perturb the optical and electrochemical properties of the NiII porphyrin. NiII porphyrin 9 is diamagnetic with a low-spin NiII center in solution but becomes paramagnetic with a five-coordinated NiII center with high-spin (S = 1) state in the solid state...
April 10, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28388138/fragmentation-dynamics-of-meso-tetraphenyl-iron-iii-porphyrin-chloride-dication-under-energy-control
#19
B Li, A R Allouche, J Bernard, R Brédy, D B Qian, X Ma, S Martin, L Chen
Meso-tetraphenyl iron (III) porphyrin chloride dications (FeTPPCl(2+))(*) were prepared in collisions with F(+) and H(+) at 3 keV. The dominant fragmentation channels were observed to involve the loss of the Cl atom and the successive loss of neutral phenyl groups for both collisional systems. The mass spectra in correlation with the deposited excitation energy distributions of the parent ions for the main fragmentation channels were measured by using the collision induced dissociation under energy control method...
March 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28388041/theory-and-calculation-of-the-phosphorescence-phenomenon
#20
Gleb Baryshnikov, Boris Minaev, Hans Ågren
Phosphorescence is a phenomenon of delayed luminescence that corresponds to the radiative decay of the molecular triplet state. As a general property of molecules, phosphorescence represents a cornerstone problem of chemical physics due to the spin prohibition of the underlying triplet-singlet emission and because its analysis embraces a deep knowledge of electronic molecular structure. Phosphorescence is the simplest physical process which provides an example of spin-forbidden transformation with a characteristic spin selectivity and magnetic field dependence, being the model also for more complicated chemical reactions and for spin catalysis applications...
April 7, 2017: Chemical Reviews
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