Oligothia Dendrimers for the Formation of Gold Nanoparticles

D’Aléo, Anthony; Williams, René M.; Osswald, Friederike; Prasad, Edamana; Hahn, Uwe; Heyst, Jeroen van; Tichelaar, F.D.; Vögtle, Fritz; Cola, Luisa De

doi:10.1002/adfm.200400101

Cited by 34 publications

(11 citation statements)

References 59 publications

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“…However, the multiple binding sites of the heptameric ligands 1-4 are expected to provide nanoparticles with increased stabilities due to kinetic stabilization. [50,80] As a preliminary test reaction, Eglinton conditions (55 8C in pyridine) applied to Au-1 gold particles led to coagulation of particles, pointing at the limited stability of the particles coated with such heptameric ligands under these conditions. A mild alternative is the coupling conditions developed by Hay, which profit from the readily soluble Cu(I)-tetramethylethylenediamine (TMEDA) complex.…”

Section: Formation Of Nanoparticle Superstructures By Acetylene Couplingmentioning

confidence: 99%

Gold Nanoparticles Stabilized by Acetylene‐Functionalized Multidentate Thioether Ligands: Building Blocks for Nanoparticle Superstructures

Peterle

Ringler

Mayor

2009

Adv Funct Materials

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Aiming at the formation of inorganic/organic hybrid gold nanoparticle superstructures, the design and synthesis of acetylene‐monofunctionalized multidentate thioether ligands and their ability to stabilize gold nanoparticles are presented. Rather monodisperse gold particles with diameters of about 1 nm are obtained, which are coated by a small number of ligands, each comprising a silyl‐protected acetylene. The acetylene is attached at the end of a rigid ethynylene‐phenylene unit of variable length, leading to functionalized gold nanoparticles carrying acetylenes at different distances from the nanoparticle surface. These particles are interlinked by diacetylene formation and are investigated by transmission electron microscopy and UV/vis spectroscopy, revealing the formation of nanoparticle aggregates and small superstructures such as dimers or trimers while the nanoparticles themselves retain their integrity. The interparticle distance in small nanoparticle superstructures reflects the ethynylene‐phenylene spacer length corroborating the wet chemical interlinking as the origin of these organic/inorganic hybrid structures.

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Section: Formation Of Nanoparticle Superstructures By Acetylene Couplingmentioning

confidence: 99%

Gold Nanoparticles Stabilized by Acetylene‐Functionalized Multidentate Thioether Ligands: Building Blocks for Nanoparticle Superstructures

Peterle

Ringler

Mayor

2009

Adv Funct Materials

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“…The advantage of dendrimers over polymers is the control over their monodispersity. The molecular structures of reported dendritic ligands vary from stiff arylic sulfides40, 41 to partially flexible benzylic/arylic sulfides42 and highly flexible benzylic thioether dendrimers 43. Superior stability and monodispersity has been reported for the latter.…”

Section: Introductionmentioning

confidence: 99%

Gold Nanoparticles Stabilized by Thioether Dendrimers

Hermes

Sander

Peterle

et al. 2011

Chemistry A European J

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Ligand-stabilized gold nanoparticles (Au NPs) are promising materials for nanotechnology with applications in electronics, catalysis, and sensors. These applications depend on the ability to synthesize stable and monodisperse NPs. Herein, the design and synthesis of two series of dendritic thioether ligands and their ability to stabilize Au NPs is presented. The dendrimers have 1,3,5-trisubstituted benzene branching units bridged by either meta-xylene or ethylene moieties. A comparison between the two ligands shows how both size control and the stability of the NPs are influenced by the nature of the ligand-NP wrapping interaction. The meta-xylene-bridged ligands provided NPs with a narrow size distribution centered around a diameter of 1.2 nm, whereas the NPs formed with ethylene-bridged dendrimers lack long-term stability with NP aggregation detected by UV/Vis spectroscopy and transmission electron microscopy. The bulkier tert-butyl-functionalized meta-xylene bridges form larger ligand shells that inhibit further growth of the NPs and thus provide a simple route to stable and monodisperse Au NPs that may find use as functional components in nanoelectronic devices.

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“…Due to their unique branched structure, dendrimers are intrinsically original scaffolds for the preparation of photoactive molecular devices, [1][2][3][4][5][6][7][8][9] and a particularly appealing fea-ture is based on the possibility of producing multichromophoric ensembles that mimic the characteristic features of the natural photosynthetic system. [10,11] In such dendrimerbased photoactive devices, an array of peripheral chromophores is able to transfer the collected energy to the central core of the dendrimer, thus mimicking the natural light-harvesting complex where antenna molecules collect sunlight and channel the absorbed energy to a single reaction center.…”

Section: Introductionmentioning

confidence: 99%

Structure‐Dependent Photoinduced Electron Transfer in Fullerodendrimers with Light‐Harvesting Oligophenylenevinylene Terminals

Armaroli

Accorsi

Clifford

et al. 2006

Chemistry An Asian Journal

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Oligophenylenevinylene (OPV)-terminated phenylenevinylene dendrons G1-G4 with one, two, four, and eight "side-arms", respectively, were prepared and attached to C60 by a 1,3-dipolar cycloaddition of azomethine ylides generated in situ from dendritic aldehydes and N-methylglycine. The relative electronic absorption of the OPV moiety increases progressively along the fullerodendrimer family C60G1-C60G4, reaching a 99:1 ratio for C60G4 (antenna effect). UV/Vis and near-IR luminescence and transient absorption spectroscopy was used to elucidate photoinduced energy and electron transfer in C60G1-C60G4 as a function of OPV moiety size and solvent polarity (toluene, dichloromethane, benzonitrile), taking into account the fact that the free-energy change for electron transfer is the same along the series owing to the invariability of the donor-acceptor couple. Regardless of solvent, all the fullerodendrimers exhibit ultrafast OPV-->C60 singlet energy transfer. In CH2Cl2, the OPV-->C60 electron transfer from the lowest fullerene singlet level ((1)C60*) is slightly exergonic (deltaG(CS) approximately = 0.07 eV), but is observed, to an increasing extent, only in the largest systems C60G2-C60G4 with lower activation barriers for electron transfer. This effect has been related to a decrease of the reorganization energy upon enlargement of the molecular architecture. Structural factors are also at the origin of an unprecedented OPV-->C60 electron transfer observed for C60G3 and C60G4 in apolar toluene, whereas in benzonitrile, electron transfer occurs in all cases. Monitoring of the lowest fullerene triplet state by sensitized singlet oxygen luminescence and transient absorption spectroscopy shows that this level is populated through intersystem crossing and is not involved in photoinduced electron transfer.

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Oligothia Dendrimers for the Formation of Gold Nanoparticles

Cited by 34 publications

References 59 publications

Gold Nanoparticles Stabilized by Acetylene‐Functionalized Multidentate Thioether Ligands: Building Blocks for Nanoparticle Superstructures

Gold Nanoparticles Stabilized by Acetylene‐Functionalized Multidentate Thioether Ligands: Building Blocks for Nanoparticle Superstructures

Gold Nanoparticles Stabilized by Thioether Dendrimers

Structure‐Dependent Photoinduced Electron Transfer in Fullerodendrimers with Light‐Harvesting Oligophenylenevinylene Terminals

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