Biological properties of water-soluble phosphorhydrazone dendrimers

1984-8250Dendrimers are hyperbranched and perfectly defined macromolecules, constituted of branches emanating from a central core in an iterative fashion. Phosphorhydrazone dendrimers constitute a special family of dendrimers, possessing one phosphorus atom at each branching point. The internal structure of these dendrimers is hydrophobic, but hydrophilic terminal groups can induce the solubility of the whole structure in water. Indeed, the properties of these compounds are mainly driven by the type of terminal groups their bear; this is especially true for the biological properties. For instance, positively charged terminal groups are efficient for transfection experiments, as drug carriers, as anti-prion agents, and as inhibitor of the aggregation of Alzheimer's peptides, whereas negatively charged dendrimers have anti-HIV properties and can influence the human immune system, leading to anti-inflammatory properties usable against rheumatoid arthritis. This review will give the most representative examples of the biological properties of water-soluble phosphorhydrazone dendrimers, organized depending on the type of terminal groups they bear

FT-Raman, FT-IR spectroscopic and DFT studies of hexaphenoxycyclotriphosphazene

International audienceThe FTIR and FT Raman measurements of zero G c 0 ′ -H and first G c 1 ′ -H generations of phosphorus dendrimer built from cyclotriphosphazene core with phenoxy and deuterophenoxy terminal groups have been performed. In order to evaluate how much the frequencies, shift when changing the electronics of the system the FTIR and FT Raman spectra of phosphorus‒containing dendron with five terminal oxybenzaldehyde and one ester function G c i ′ have been also studied. Structural optimization and normal mode analysis were obtained for G c 0 ′ -H and G c 0 ′ -D by the density functional theory (DFT). It is discovered that dendrimer molecule exists in a stable conformation with six phenoxy terminal groups spaced above and below the flat cyclotriphosphazene core. Optimized geometric bond length and angles obtained by DFT show good agreement with a previously-published X-ray study. The phenoxy terminal groups are characterized by the well-defined line at 993 cm−1 in the experimental Raman spectrum of G c 0 ′ -H and by line at 960 cm−1 in the Raman spectrum of G c 0 ′ -D. Relying on DFT calculations a complete vibrational assignment is proposed for the studied dendrimers. The frequencies and relative intensity of the bands at 1589, 1487 cm−1 in the IR spectra show marked difference in dependence of the substituents on the aromatic ring

Raman spectroscopy studies of phosphorus dendrimers with phenoxy and deuterophenoxy terminal groups

International audienceThe FT-IR and FT–Raman measurements of 6 generations of phosphorus dendrimers G′ci built from cyclotriphosphazene core with phenoxy and deuterophenoxy terminal groups have been performed. Spectra of dendrimers depends on the ratio of end groups and repeated units. This ratio tends to be r – 1 (r – functionality of repeated unit), and becomes constant, when the generation number is above 3. Experimental Raman spectra of generations of dendrimers are very closely similar in accordance with the theory. Structural optimization and normal mode analysis were obtained for G′c1 by the density functional theory (DFT). Calculations have shown that each OC6H4CHNN(CH3) moiety is flat and six repeating units are located above and below the nearly flat cyclotriphosphazene ring. Optimized geometric bond length and angles obtained by DFT show good agreement with the experiment. The phenoxy terminal groups are characterized by the well-defined line at 1008 cm−1 in the experimental Raman spectrum of G′c1-H and by line at 968 cm−1 in the Raman spectrum of G′c1-D. The medium-intensity line in the Raman spectra of G′c1-H and G′c1-D at 1576 cm−1 refer to the repeating units vibrations

Synthesis and application of phosphorus dendrimer immobilized azabis(oxazolines)

Phosphorus dendrimer immobilized azabis(oxazoline) ligands can be efficiently synthesized up to the third generation with 48 ligand molecules being attached to the periphery using click chemistry. The so-assembled macromolecules were evaluated in copper(II)-catalyzed asymmetric benzoylations, showing good yields and enantioselectivities. Moreover, the copper(II)-catalysts could be readily recovered and reused in several cycles. The globular structure of the dendritic ligands seems to prevent interference of the triazole moieties in the catalysis, contrasting MeOPEG or polystyrene bound ligands of the same type