Author: Shawkat M. Aly

Reactivity of CuI and CuBr toward Et2S: a reinvestigation on the self-assembly of luminescent copper(I) coordination polymers.

2010

CuI reacts with SEt(2) in hexane to afford the known strongly luminescent 1D coordination polymer [(Et(2)S)(3){Cu(4)(mu(3)-I)(4)}](n) (1). Its X-ray structure has been redetermined at 115, 235, and 275 K in order to address the behavior of the cluster-centered emission and is built upon Cu(4)(mu(3)-I)(4) cubane-like clusters as secondary building units (SBUs), which are interconnected via bridging SEt(2) ligands. However, we could not reproduce the preparation of a coordination polymer with composition [(Et(2)S)(3){Cu(4)(mu(3)-Br)(4)}](n) as reported in Inorg. Chem. 1975, 14, 1667. In contrast, the autoassembly reaction of SEt(2) with CuBr results in the formation of a novel 1D coordination…

chemistry.chemical_classificationCoordination polymerInorganic chemistrychemistry.chemical_elementBridging ligandPolymerCrystal structureCopperInorganic Chemistrychemistry.chemical_compoundCrystallographychemistryDensity functional theorySBusPhysical and Theoretical ChemistryLuminescenceInorganic chemistry

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Evidence for reverse pathways and equilibrium in singlet energy transfers between an artificial special pair and an antenna

2013

A dyad, 1, built on an artificial special pair (bis(meso-nonyl)zinc(II)porphyrin), [Zn2], a spacer (biphenylene), a bridge (1,4-benzene), and an antenna (di-meso-(3,5-di(t-butyl)phenyl)porphyrin free base), FB, is prepared by Suzuki coupling and is analyzed by absorption and steady state, and time-resolved emission spectroscopy at 298 and 77 K. Using bases from the Förster theory, evidence for two pathways for S 1 energy transfer, FB* → [Zn2], and [Zn2]* → FB, along with their respective rates, k ET ( S 1)1 and k ET ( S 1)-1, are extracted from the comparison of the fluorescence decays monitored at the emission maximum. At 77 K, the unquenched (1.79 ([Zn2]) and 10.6 ns (FB)) and quenched c…

chemistry.chemical_compoundChemistryFree baseGeneral ChemistrySinglet stateEmission spectrumSteady state (chemistry)Atomic physicsBiphenyleneAbsorption (electromagnetic radiation)FluorescencePorphyrinJournal of Porphyrins and Phthalocyanines

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Rational synthetic design of well-defined Pt(bisethynyl)/Zn(porphyrin) oligomers for potential applications in photonics

2011

Well-defined oligomers of 1, 2, 3 and 4 units built upon the very soluble bis-1,15-(1,4-ethynylbenzene)-3,7,13,17-tetramethyl-2,8,12,18-tetrakis(n-hexyl) zinc(II) porphyrin ligand and the trans-bis(tri-n-butylphosphine)platinum(II) linker, with acetylene or trimethylsilane as end groups, has been prepared in the presence of a dichloromethane/diethylamine mixture (1 : 1 v/v) and CuX (X = Cl, I) at room temperature, analogue to a Sonogashira coupling. The new monodisperse organometallic oligomers were characterized by 1H, 31P NMR, UV-visible spectroscopies and MALDI-TOF mass spectrometry. The methyl groups placed at the 3,7,13,17-positions induces the locking of the C6H4 fragment in a perpend…

DiethylamineDimerSonogashira couplingTrimethylsilaneGeneral ChemistryChromophorePhotochemistryPorphyrinCatalysischemistry.chemical_compoundMonomerchemistryTetramerMaterials ChemistryNew Journal of Chemistry

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Random Structural Modification of a Low-Band-Gap BODIPY-Based Polymer

2017

International audience; A BODIPY thiophene polymer modified by extending conjugation of the BODIPY chromophore is reported. This modification induces tunability of energy levels and therefore absorption wavelengths in order to target lower energies.

Materials scienceBand gapthin-film transistors02 engineering and technology010402 general chemistryPhotochemistry[ CHIM ] Chemical Sciences01 natural scienceschemistry.chemical_compoundmolecular-orbital methodsorganometallic compounds[CHIM]Chemical SciencesPhysical and Theoretical Chemistrydensity-functional theoryAbsorption (electromagnetic radiation)valence basis-setsdistyryl-boradiazaindaceneschemistry.chemical_classificationPolymer modifiedfield-effect transistorspi-conjugated copolymers[CHIM.MATE]Chemical Sciences/Material chemistryPolymerChromophore021001 nanoscience & nanotechnology0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsWavelengthsolar-cellsGeneral Energychemistry[ CHIM.MATE ] Chemical Sciences/Material chemistryextended basis-setsBODIPY0210 nano-technologyThe Journal of Physical Chemistry C

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Effect of t-BuS vs. n-BuS on the topology, Cu⋯Cu distances and luminescence properties of 2D Cu4I4/RS(CH2)4SR metal–organic frameworks

2011

CuI reacts with RS(CH2)4SR (R = n-Bu (L1); t-Bu (L2)) to afford the 2D coordination polymers [Cu4I4{μ-RS(CH2)4SR}2]n (R = n-Bu (1); t-Bu (2)). Their grid networks exhibit nodal Cu4(μ3-I)4 clusters interconnected by dithioethers with mean Cu⋯Cu distances of 2.7265(10) and 2.911(2) A for 1 and 2, respectively. This difference translates in a blue shift of the solid state emission bands and a decrease in emission lifetimes when trading R = n-Bu to the bulky t-Bu.

chemistry.chemical_classificationCrystallographychemistryComputational chemistryMaterials ChemistrySolid-stateMetal-organic frameworkGeneral ChemistryPolymerLuminescenceCatalysisTopology (chemistry)BlueshiftNew Journal of Chemistry

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Copper(I) Halides (X = Br, I) Coordinated to Bis(arylthio)methane Ligands: Aryl Substitution and Halide Effects on the Dimensionality, Cluster Size a…

2014

Bis(phenylthio)methane (L1) reacts with CuI to yield the 1D-coordination polymer [{Cu4(μ3-I)4}(μ-L1)2]n (1) bearing cubane Cu4I4 clusters as connecting nodes. The crystal structures at 115, 155, 195, and 235 K provided evidence for a phase transition changing from the monoclinic space group C2/c to P21/c. The self-assembly process of CuI with bis(p-tolylthio)methane (L2), bis(4-methoxyphenylthio)methane (L3), and bis(4-bromo-phenylthio)methane (L4) affords the 1D-coordination polymers [{Cu4(μ3-I)4}(μ-Lx)2]n (x = 2, 3, or 4). Compounds 2 and 4 are isostructural with C2/c low temperature polymorph of 1, whereas the inversion centers and 2-fold axes are lost in 3 (space group Cc). The use of b…

Steric effectsArylGeneral ChemistryCrystal structureCondensed Matter PhysicsPhotochemistryMethanechemistry.chemical_compoundCrystallographychemistryCubaneRibbon[CHIM]Chemical SciencesGeneral Materials ScienceIsostructuralComputingMilieux_MISCELLANEOUSMonoclinic crystal system

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Design and photophysical properties of zinc(II) porphyrin-containing dendrons linked to a central artificial special pair.

2011

The click chemistry synthesis and photophysical properties, notably photo-induced energy and electron transfers between the central core and the peripheral chromophores of a series of artificial special pair-dendron systems (dendron = G1, G2, G3; Gx = zinc(II) tetra-meso-arylporphyrin-containing polyimides) built upon a central core of dimethylxanthenebis(metal(II) porphyrin) (metal = zinc, copper), are reported. The dendrons act as singlet and triplet energy acceptors or donors, depending on the dendrimeric systems. The presence of the paramagnetic d(9) copper(II) in the dendrimers promotes singlet-triplet energy transfer from the zinc(II) tetra-meso-arylporphyrin to the bis(copper(II) por…

DendrimersMolecular StructureChemistryMetalloporphyrinsOrganic Chemistrychemistry.chemical_elementGeneral ChemistryZincChromophorePhotochemistryCopperPorphyrinCatalysisElectron transferchemistry.chemical_compoundZincEnergy TransferDendrimerClick ChemistrySinglet statePhosphorescenceCopperChemistry (Weinheim an der Bergstrasse, Germany)

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Dendron to central core S1-S1 and S2-S(n) (n1) energy transfers in artificial special pairs containing dendrimers with limited numbers of conformatio…

2013

Two dendrimers consisting of a cofacial free-base bisporphyrin held by a biphenylene spacer and function- alized with 4-benzeneoxomethane (5-(4-benzene)tri-10,15,20-(4-n-octyl- benzene)zinc(II)porphyrin) using either five or six of the six available meso-positions, have been synthesized and characterized as models for the an- tenna effect in Photosystems I and II. The presence of the short linkers, -CH2O-, and long C8H17 soluble side chains substantially reduces the number of conformers (foldamers) compared with classic dendrimers built with longer flexible chains. This simpli- fication assists in their spectroscopic and photophysical analysis, notably with respect to fluorescence resonance…

AnthracenesDendrimersMolecular StructureStereochemistryMetalloporphyrinsOrganic ChemistryGeneral ChemistryBiphenylenePorphyrinFluorescenceAcceptorCatalysischemistry.chemical_compoundCrystallographyFörster resonance energy transferchemistryEnergy TransferModels ChemicalDendrimerSinglet stateConformational isomerismChemistry (Weinheim an der Bergstrasse, Germany)

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Energy transfers in monomers, dimers, and trimers of zinc(II) and palladium(II) porphyrins bridged by rigid Pt-containing conjugated organometallic s…

2009

A series of linear monomers (spacer-M(P)), dimers (M(P)-spacer-M'(P)), and trimers (M(P)-spacer-M'(P)-spacer-M(P)) of spacer/metalloporphyrin systems (M' = Zn, M = Zn, Pd, P = porphyrin, and spacer = trans-C(6)H(4)C[triple bond]CPtL(2)C[triple bond]CC(6)H(4)- (L = PEt(3))) including mixed metalloporphyrin compounds, were synthesized and characterized. The S(1) and T(1) energy transfers Pd(P)*--Zn(P) occur with rates of approximately 2 x 10(9) s(-1), S(1), and 0.15 x 10(3) (slow component) and 4.3 x 10(3) s(-1) (fast component), T(1). On the basis of a literature comparison with a related dyad, the Pt atom in the conjugated chain slows down the transfers. The excitation in the absorption ban…

Models MolecularTime FactorsOrganoplatinum CompoundsStereochemistryMetalloporphyrinsMolecular Conformationchemistry.chemical_elementZincConjugated system010402 general chemistryLigands01 natural sciences7. Clean energyAbsorptionInorganic Chemistrychemistry.chemical_compoundAtomtrimerPhysical and Theoretical ChemistryComputingMilieux_MISCELLANEOUSmetalloporphyrinenergy transfer010405 organic chemistrySpectrum AnalysiszincmonomerdimerpalladiumPorphyrin0104 chemical sciences3. Good health[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistryCrystallographyMonomerchemistryAbsorption bandLuminescent Measurements[ CHIM.THEO ] Chemical Sciences/Theoretical and/or physical chemistryconjugated organometallic spacerDimerizationExcitationPalladium

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Design of Triads for Probing the Direct Through Space Energy Transfers in Closely Spaced Assemblies

2013

Using a selective stepwise Suzuki cross-coupling reaction, two trimers built on three different chromophores were prepared. These trimers exhibit a D(^)A1-A2 structure where the donor D (octa-β-alkyl zinc(II)porphyrin either as diethylhexamethyl, 10a, or tetraethyltetramethyl, 10b, derivatives) through space transfers the S1 energy to two different acceptors, di(4-ethylbenzene) zinc(II)porphyrin (A1; acceptor 1) placed cofacial with D, and the corresponding free base (A2; acceptor 2), which is meso-meso-linked with A1. This structure design allows for the possibility of comparing two series of assemblies, 9a,b (D(^)A1) with 10a,b (D(^)Â1-A2), for the evaluation of the S1 energy transfer for…

Models MolecularMetalloporphyrinsChemistryEnergy transferMolecular Conformationchemistry.chemical_elementFree baseZincChromophoreSpace (mathematics)AcceptorPorphyrinFluorescenceInorganic ChemistryCrystallographychemistry.chemical_compoundEnergy TransferDrug DesignPhysical and Theoretical ChemistryAtomic physicsInorganic Chemistry

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Acceleration of the through space S1 energy transfer rates in cofacial bisporphyrin bio-inspired models by virtue of substituents effect on the Först…

2011

The singlet k(ET) for cofacial β-octaalkylporphyrin/bis(meso-aryl)porphyrin dyads increases linearly with the gap between the donor-acceptor 0-0 fluorescence peaks at 77 K.

PorphyrinsEnergy transferLight-Harvesting Protein ComplexesMetals and AlloysAntenna effectGeneral ChemistrySpace (mathematics)PorphyrinFluorescenceCatalysisSurfaces Coatings and FilmsElectronic Optical and Magnetic Materialschemistry.chemical_compoundAccelerationSpectrometry FluorescenceBacterial ProteinsEnergy TransferModels ChemicalchemistryChemical physicsMaterials ChemistryCeramics and CompositesSinglet stateAtomic physicsPhotosystemChemical Communications

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Is the special pair structure a good strategy for the kinetics during the last step of the energy transfer with the nearest antenna? A chemical model…

2013

A cofacial bis(Mg(II)porphyrin)-C(6)H(4)-free base ([Mg(2)]-bridge-FB) dyad shows S(1) energy transfer in both directions and much slower rates than similar monoporphyrin systems are observed.

Molecular StructureMetalloporphyrinsEnergy transferKineticsMetals and AlloysStructure (category theory)General ChemistryPorphyrinMolecular physicsCatalysisSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsBase (group theory)chemistry.chemical_compoundKineticsZincchemistryEnergy TransferModels ChemicalComputational chemistryMaterials ChemistryCeramics and CompositesMoleculeMagnesiumAntenna (radio)Chemical communications (Cambridge, England)

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