Photoresponsive Dendrimers Research Articles

A novel nanocomposite material prepared by intercalating photoresponsive dendrimers into a layered double hydroxide

A novel combination for an inorganic-organic nanocomposite material was demonstrated. Anthryl dendron, i.e., poly(amidoamine) dendron with an anthracene chromophore group at the focal point, was incorporated in the interlayer space of ZnAl-NO{sub 3} type layered double hydroxide (LDH) through an anion-exchange reaction. The photoabsorption and fluorescence properties of the resulting material were different from those of the bare anthryl dendron molecule. It was suggested that the change in photochemical properties was due to the organization and pi-pi interaction of anthracene chromophores within the interlayer of the LDH. - Graphical abstract: A novel inorganic-organic nanocomposite material, a layered double hydroxide (LDH) containing photoresponsive dendrimers in the interlayer space, was successfully prepared through an ion-exchange reaction. The resulting material exhibited unique photochemical properties, compared to those of the bare photoresponsive dendrimer molecule.

Synthesis and Photochemical Characteristics of Amphiphilic Enediyne Dendrimers

Abstract Amphiphilic enediyne-cored dendrimers were prepared as pure cis and trans isomers. All dendrimers were fluorescent to give fluorescence quantum yield of 0.10–0.64, and they underwent efficient photochemical isomerization with quantum yields of 0.22–0.50 in THF. In water, other photochemical reactions took place. Fluorescence or triplet lifetimes were also strongly affected by dendrimer generation and solvent polarity. The structure–photochemical property relationship of new photoresponsive dendrimers is discussed.

Synthesis, excited state properties, and dynamic structural change of photoresponsive dendrimers

This article reviews recent advances in research of the dendrimer synthesis in connection with the design, synthesis and reaction of photoresponsive dendrimers. Dendrimers with photoreversible stilbene cores undergo mutual cis–trans isomerization in organic solvents to give photostationary state mixture of cis and trans isomers. Even the fourth generation (G4) stilbene dendrimer with molecular weight as high as 6500 underwent cis–trans photoisomerization within the lifetime of the excited singlet state. The large dendron group surrounding the photoreactive core may affect the excited state properties of the core to increase the efficiency of photoisomerization and/or decrease the fluorescence efficiency. The photochemistry of stilbene dendrimers with various types of dendron groups, and azobenzene dendrimers is discussed. Furthermore, recent advance of dendrimer syntheses and the possibility of their application to construct photoresponsive large molecules are discussed.

Design and synthesis of photoresponsive poly(benzyl ester) dendrimers with all-azobenzene repeating units.

A novel class of dendrons and dendrimers containing all-azobenzene units (up to 29 azobenzene groups) was designed and synthesized by the convergent method using a protected orthogonal AB(2) monomer (10) and tetra-functionalized core (11) as building blocks. The preparation of the key monomer (10) involved condensation of a protected nitroso compound (9) and 5-aminoisophthalic acid. These are the first examples of photoresponsive dendrimers with all-azobenzene repeating units. [structure: see text]

Photoresponsive Dendrimers: Syntheses and Characterizations of Anthracenes Bearing Dendritic Substituents

Abstract A new photoreactive anthracenyl dendron undergoes a reversible photocyclization to form a dendrimer.