Amphiphilic Dendrimers with Heteroleptic Bis([2,2?: 6?,2?]terpyridine)-Ruthenium(II) Cores

Nonviral gene delivery with dendritic self-assembling architectures

In this review, we outline the concept and applicability of self-assembling dendrimers for gene-delivery applications. Low-molecular-weight, well-defined cationic dendritic arrays which have been modified with hydrophobic domains can form self-organized multivalent systems that have significant advantages over nonassembling, high-molecular-weight/polymeric gene vectors. Particular structural variations have been highlighted with respect to the individual components of the displayed dendritic amphiphiles, namely, the employed amine termini, the hydrophobic segment, the size of the dendritic array, and the integration of special features such as targeting ability and cleavability/degradability, which can all have a crucial effect on gene-transfection efficiencies. Accordingly, the scientific efforts to create new synthetic gene-delivery vectors to act as promising in vivo transfection agents in the future will be presented and discussed here.

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

Pd-catalyzed Sonogashira cross-coupling reactions were used to synthesize novel π-conjugated oligothienylene-ethynylene dendrons and their corresponding terpyridine-based ligands. Their complexation with Ru(II) led to interesting novel metallodendrimers with rich spectroscopic properties. All new compounds were fully characterized by ¹H and ¹³C NMR, as well as MALDI–TOF mass spectra. Density functional theory (DFT) calculations performed on these complexes gave more insight into the molecular orbital distributions. Photophysical and electrochemical studies were carried out in order to elucidate structure–property relationships and the effect of the dendritic structure on the metal complexes. Photophysical studies of the complexes revealed broad absorption spectra covering from 250 to 600 nm and high molar extinction coefficients. The MLCT emission of these complexes were significantly red-shifted (up to 115 nm) compared to the parent [Ru(tpy)₂]²⁺ complex.

Effects of structural modification on gene transfection and self-assembling properties of amphiphilic dendrimers

A library of novel amphiphilic, self-assembling dendrimers was designed and synthesised to evaluate the effects of structural changes on transfection efficiency.

Convenient Synthesis of 1 → 3 C-Branched Dendrons

A facile, efficient synthesis of 1 --> 3 C-branched polyamide dendrons is described. Treatment of acryloyl chloride with 1 --> 3 C-branched amines, e.g., di-tert-butyl 4-[2-(tert-butoxycarbonyl)ethyl]-4-aminoheptanedioate, gave the corresponding acrylamides in high yields, which upon reaction with nitromethane generated the homologated nitroalkane-polyesters. Finally, nitroalkane alkylation with 2 equiv of the acrylamides, followed by nitro group reduction, afforded the desired amino-polyesters.