The specific functionalization of cyclotriphosphazene for the synthesis of smart dendrimers

Dendritic Pyridine-Imine Copper Complexes as Metallo-Drugs

Since the discovery of cisplatin in the 1960s, the search for metallo-drugs that are more efficient than platinum complexes with negligible side effects has attracted much interest. Among the other metals that have been examined for potential applications as anticancer agents is copper. The interest in copper was recently boosted by the discovery of cuproptosis, a recently evidenced form of cell death mediated by copper. However, copper is also known to induce the proliferation of cancer cells. In view of these contradictory results, there is a need to find the most suitable copper chelators, among which Schiff-based derivatives offer a wide range of possibilities. Gathering several metal complexes in a single, larger entity may provide enhanced properties. Among the nanometric objects suitable for such purpose are dendrimers, precisely engineered hyperbranched macromolecules, which are outstanding candidates for improving therapy and diagnosis. In this review article, we present an overview of the use of a particular Schiff base, namely pyridine-imine, linked to the surface of dendrimers, suitable for complexing copper, and the use of such dendrimer complexes in biology, in particular against cancers.

BODIPY precursors and their cyclotriphosphazene Derivatives: Synthesis, photochemical properties and their application in PDT

Photodynamic therapy (PDT) is a treatment method consisting of common combination of oxygen, light energy and a light absorbing molecule called a photosensitizer. In this work, four new compounds consisting of BODIPY precursors and BODIPY-cyclotriphosphazene derivatives were synthesized to investigate the PDT effects. The chemical structures of the compounds were characterized and then their photophysical properties were determined by spectroscopic techniques. The precursor BODIPYs and their cyclotriphosphazene derivatives exhibited similar properties such as strong absorption intensity, high photostability and low fluorescence profile in the NIR region. Additionally, the singlet oxygen production capacities of these compounds were determined using the photobleaching technique of 1,3-diphenylisobenzofuran (DPBF) under light illumination. By introducing iodine atoms into the molecule, which are responsible for the intersystem transition (ISC) enhancement, a more efficient singlet oxygen production was achieved in both the iodinated-BODIPY and its cyclotriphosphazene derivative. Anticancer activities of the precursor BODIPYs and their cyclotriphosphazene derivatives in the absence and presence of light illumination were evaluated on cancerous cell lines (PC3 and DU145) and non-tumorigenic prostate epithelial PNT1a cell. The compounds triggered the death of cancer cell PC3 the more significantly in the presence of red light compared to the healthy cells (PNT1a).

"Click" Chemistry for the Functionalization of Graphene Oxide with Phosphorus Dendrons: Synthesis, Characterization and Preliminary Biological Properties

Two families of phosphorhydrazone dendrons having either an azide or an alkyne linked to the core and diverse types of pyridine derivatives as terminal functions have been synthesized and characterized. These dendrons were grafted via click reaction to graphene oxide (GO) functionalized with either alkyne or azide functions, respectively. The resulting modified-GO and GO-dendrons materials have been characterized by Fourier Transform Infrared (FTIR), Raman spectroscopy (RS), and Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) analyses. In addition, the free dendrons and the dendrons grafted to GO were tested toward cancerous (HCT116) and non-cancerous (RPE1) cell lines.

Interplay between Nanoparticles and Phosphorus Dendrimers, and Their Properties

This review presents the state of the art of interactions between two different families of nanoobjects: nanoparticles-mainly metal nanoparticles, and dendrimers-mainly phosphorhydrazone dendrimers (or dendrons). The review firstly presents the encapsulation/protection of existing nanoparticles (organic or metallic) by phosphorus-based dendrimers and dendrons. In the second part, several methods for the synthesis of metal nanoparticles, thanks to the dendrimer that acts as a template, are presented. The properties of the associations between dendrimers and nanoparticles are emphasized throughout the review. These properties mainly concern the elaboration of diverse types of hybrid materials, some of them being used as sensitive chemosensors or biosensors. Several examples concerning catalysis are also given, displaying in particular the efficient recovery and reuse of the catalytic entities.

Strategies for the Preparation of Phosphorus Janus Dendrimers and Their Properties

Dendrimers, being highly branched monodispersed macromolecules, predominantly exhibit identical terminal functionalities within their structural framework. Nonetheless, there are instances where the presence of two distinct surface functionalities becomes advantageous for the fulfilment of specific properties. To achieve this objective, one approach involves implementing Janus dendrimers, consisting of two dendrimeric wedges terminated by dissimilar functionalities. The prevalent method for creating these structures involves the synthesis of dendrons that possess a core functionality that complements that of a second dendron, facilitating their coupling to generate the desired dendrimers. In this comprehensive review, various techniques employed in the fabrication of phosphorus-based Janus dendrimers are elucidated, displaying the different coupling methodologies employed between the two units. The advantages of phosphorus dendrimers over classic dendrimers will be shown, as the presence of at least one phosphorus atom in each generation allows for the easy monitoring of reactions and the confirmation of purity through a simple technique such as ³¹P NMR, as these structures typically exhibit easily interpretable patterns.

One-Pot Synthesis of Cyclomatrix-Type Polyphosphazene Microspheres and Their High Thermal Stability

Highly cross-linked inorganic and organic hybrid cyclomatrix-polyphosphazenes microspheres (C-PPZs) have been successfully synthesized by a one-pot polymerization technique between hexachlorocyclotriphosphazene and p-phenylenediamine in the presence of triethylamine (TEA), and they were used for enhancing the flame retardancy of epoxy resins (EPs). A thermoset EP was prepared by incorporating different percentages (2, 5, and 10%) of C-PPZs into diglycidyl ether of bisphenol A (DGEBA). The results reveal that the size and morphology of the microspheres can be tuned by varying the synthesis temperature. The average size of C-CPPZs gradually increased from 3.1, 4.9, to 7.8 μm as the temperature was increased from 100, 120, to 200 °C, respectively. The thermogravimetric analysis showed that the C-CPPZ microspheres have good thermal stability up to 900 °C with about ∼10 wt % mass loss for C-CPPZs formed at 200 °C compared to ∼30 wt % mass loss for those obtained at 100 and 120 °C. The 10% loss at 900 °C is much lower than the previous research concerning the thermal stability of cyclophosphazene, in which more weight losses were observed at lower temperatures. The resulting C-CPPZ microspheres were characterized by spectroscopic and imaging techniques including Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, elemental mapping, and X-ray photoelectron spectroscopy.

Oligoetherols and polyurethane foams based on cyclotriphosphazene of reduced flammability

New oligoetherols with based on cyclotriphosphazene ring were synthesized by functionalization of hexachlorocyclotriphosphazene with glycidol followed by reaction with ethylene glycol and glycerol. Oligoetherols were characterized by IR, 1H-NMR, and MALDI-ToF and hydroxyl number as well as physical properties like density, viscosity and surface tension. The oligoetherols were further converted into polyurethane foams. The rigid foams of enhanced thermal stability and considerably diminished flammability were obtained and their apparent density, water uptake and polymerization shrinkage, thermal conductivity coefficient and thermal stability were determined. The flammability of foams was studied by microcalorimetric methods, horizontal flaming test and oxygen index. The obtained polyurethane foams with incorporated cyclotriphosphazene ring are self-extinguishing.

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Phosphorus-nitrogen compounds: part 53-synthesis, characterization, cytotoxic and antimicrobial activity, DNA interaction and molecular docking studies of new mono- and dispirocyclotriphosphazenes with pendant arm(s)

Mono-/dispirocyclotriphosphazenes with pendant arm(s) are robust, but they are less investigated inorganic ring systems. In this study, a series of mono (3 and 4)- and dispirocyclotriphosphazenes with 4-chloro-benzyl pendant arm(s) (13-16) was obtained from the Cl exchange reactions of hexachlorocyclotriphosphazene with sodium (N-benzyl)aminopropanoxides (1 and 2). When compound (3) reacted with excess pyrrolidine, morpholine, tetra-1,4-dioxa-8-azaspiro[4,5]decane (DASD) and piperidine, the fully substituted monospirocyclotriphosphazenes (7, 9, 10 and 12) occurred. But, the reactions of 4 with excess piperidine and morpholine produced the gem-piperidino (5)- and morpholino (6)-substituted monospirocyclotriphosphazenes, whereas the reactions of 4 with excess pyrrolidine and DASD gave the fully substituted monospirocyclotriphosphazenes (8) and (11). However, it should be indicated that these derivatives were obtained to be used for the investigation of their spectral, stereogenic and biological properties. The structures of 5, 7 and 14 were determined crystallographically. X-ray data of 5 and 14 displayed that both of compounds were chiral in solid state, and their absolute configurations were assigned as R and RR. Additionally, the antimicrobial activities of phosphazenes were investigated. Minimum inhibitory concentrations, minimal bacterial concentrations and minimum fungicidal concentrations of phosphazenes were determined. The interactions of phosphazenes with plasmid DNA were evaluated by agarose gel electrophoresis. The cytotoxic activities of compounds were studied against L929 fibroblast and DLD-1 colon cancer cells. In addition, density functional theory calculations of 5, 7 and 14 were reported, and their molecular docking studies with DNA, E. coli DNA gyrase and topoisomerase IV were presented.

Nucleophilic substitution reactions of monofunctional nucleophilic reagents with cyclotriphosphazenes containing 2,2-dioxybiphenyl units

The nucleophilic substitution reactions of mono- and bis-spiro-2,2' -dioxybiphenyl cyclotriphosphazenes (3 and 4) with cyclopropanemethylamine (5) and aniline (6) were performed in the presence of trimethylamine in THF. Five novel cyclopropanemethylamino- and anilino-substituted spiro-2,2' -dioxybiphenyl cyclotriphosphazene derivatives (7-11) were obtained from these reactions. The molecular structures of the new cyclotriphosphazene derivatives (7-11) were characterized by elemental analysis, MALDI-TOF MS, FT-IR, and NMR ( ³¹ P and ¹ H) spectroscopies. The structure of the spiro-(2,2' -dioxybiphenyl)-bis-(anilino)-cyclotriphosphazene (11) was also determined by single-crystal X-ray crystallography.

The Usefulness of Trivalent Phosphorus for the Synthesis of Dendrimers

Dendrimers are hyperbranched macromolecules, which are synthesized step-by-step by the repetition of a series of reactions. While many different types of dendrimers are known, this review focusses on the use of trivalent phosphorus derivatives (essentially phosphines and phosphoramidites) for the synthesis of dendrimers. The first part presents dendrimers constituted of phosphines at each branching point. The other parts display the use of trivalent phosphorus derivatives during the synthesis of dendrimers. Different types of reactions have been applied to phosphines. The very first examples of phosphorus-containing dendrimers were obtained by the alkylation of phosphines. Then, several families of dendrimers were elaborated by reaction of phosphoramidites. Such a type of reaction is the base of the solid phase synthesis of oligonucleotides; it has been applied in particular for the synthesis of dendrimers constituted of oligonucleotides. Finally, the Staudinger reaction between phosphines and azides afforded different families of dendrimers, and was at the origin of accelerated methods of synthesis of dendrimers. Besides, the reactivity of the P=N-P=S linkages created by this reaction led to very original dendritic structures.

Hybrid Porous Microparticles Based on a Single Organosilica Cyclophosphazene Precursor

Porous organosilica microparticles consisting of silane-derived cyclophosphazene bridges were synthesized by a surfactant-mediated sol-gel process. Starting from the substitution of hexachlorocyclotriphosphazene with allylamine, two different precursors were obtained by anchoring three or six alkoxysilane units, via a thiol-ene photoaddition reaction. In both cases, spherical, microparticles (size average of ca. 1000 nm) with large pores were obtained, confirmed by both, scanning and transmission electron microscopy. Particles synthesized using the partially functionalized precursor containing free vinyl groups were further functionalized with a thiol-containing molecule. While most other reported mesoporous organosilica particles are essentially hybrids with tetraethyl orthosilicate (TEOS), a unique feature of these particles is that structural control is achieved by exclusively using organosilane precursors. This allows an increase in the proportion of the co-components and could springboard these novel phosphorus-containing organosilica microparticles for different areas of technology.

Fluorescent Phosphorus Dendrimers: Towards Material and Biological Applications

Fluorescent derivatives of phosphorhydrazone dendrimers are reviewed. Diverse types of fluorophores have been used, such as pyrene, naphthol, anthracene, dansyl, diketone, phthalocyanine, maleimide, julolidine, rhodamine, fluorescein, or fluorene derivatives. The fluorescent groups can be located either as terminal groups on the surface, at the core, linked to the core (off-center), or to the branches of the dendritic structure. After fundamental research on their synthesis, these compounds have been used in the fields of catalysis, nanomaterials, OLEDs, sensors and biology/nanomedicine, in particular for monitoring transfection, or for their anti-inflammatory or anti-cancer properties.

Phosphorus Dendrimers as Nanotools against Cancers

This review concerns the use of dendrimers, especially of phosphorhydrazone dendrimers, against cancers. After the introduction, the review is organized in three main topics, depending on the role played by the phosphorus dendrimers against cancers: (i) as drugs by themselves; (ii) as carriers of drugs; and (iii) as indirect inducer of cancerous cell death. In the first part, two main types of phosphorus dendrimers are considered: those functionalized on the surface by diverse organic derivatives, including known drugs, and those functionalized by diverse metal complexes. The second part will display the role of dendrimers as carriers of anticancer “drugs”, which can be either small molecules or anticancer siRNAs, or the combination of both. In the third part are gathered a few examples of phosphorhydrazone dendrimers that are not cytotoxic by themselves, but which under certain circumstances induce a cytotoxic effect on cancerous cells. These examples include a positive influence on the human immune system and the combination of bioimaging with photodynamic therapy properties.

Cyclotriphosphazenes as Scaffolds for the Synthesis of Metallomesogens

(Amino)cyclotriphosphazenes have been used as new scaffolds for the synthesis of silver(I) metallomesogens. Two cyclotriphosphazenes, [N₃P₃(NHCy)₆] (phos-1) and nongem-trans-[N₃P₃(NHCy)₃(NMe₂)₃] (phos-2), were reacted with the silver complex having a pro-mesogenic ligand, [Ag(OTf)L] (L = CNC₆H₄{OC(O)C₆H₂(3,4,5-(OC₁₀H₂₁)₃)}-4; OTf = OSO₂CF₃), in different molar ratios, 1:1, 1:2, or 1:3, to give two series of cationic metallophosphazenes, [N₃P₃(NHCy)₆{AgL}_n](TfO)_n (phos-1.n) and nongem-trans-[N₃P₃(NHCy)₃(NMe₂)₃{AgL}_n](TfO)_n (phos-2.n) with n = 1, 2, or 3. The chemical structure of these compounds, deduced from spectroscopic techniques, was in accordance with coordination of the silver fragments "AgL" to nitrogen atoms of the phosphazene ring, whereby their number n depends on the molar ratio used. Despite the presence of the bulky substituents on the core N atoms, cyclotriphosphazenes coordinated to three "AgL" units exhibited mesomorphism at room temperature. The mesophase was characterized as columnar hexagonal according to the optical microscopy and X-ray diffraction studies. A model based on an intermolecular association in pairs of the metallocyclotriphosphazenes having three AgL units has been proposed in order to explain the mesomorphic columnar arrangement in these materials. Starting silver complex, [Ag(OTf)L], also exhibited a columnar hexagonal mesophase at room temperature.

(Amino)cyclophosphazenes as Multisite Ligands for the Synthesis of Antitumoral and Antibacterial Silver(I) Complexes

The reactivity of the multisite (amino)cyclotriphosphazene ligands, [N₃P₃(NHCy)₆] and [N₃P₃(NHCy)₃(NMe₂)₃], has been explored in order to obtain silver(I) metallophosphazene complexes. Two series of cationic silver(I) metallophosphazenes were obtained and characterized: [N₃P₃(NHCy)₆{AgL}_n](TfO)_n [n = 2, L = PPh₃ (2), PPh₂Me (4); n = 3, L = PPh₃ (3), PPh₂Me (5), TPA (TPA = 1,3,5-triaza-7-phosphaadamantane, 6)] and nongem-trans-[N₃P₃(NHCy)₃(NMe₂)₃{AgL}_n](TfO)_n [n = 2, L = PPh₃ (7), PPh₂Me (9); n = 3, L = PPh₃ (8), PPh₂Me (10)]. 5, 7, and 9 have also been characterized by single-crystal X-ray diffraction, thereby allowing key bonding information to be obtained. Compounds 2-6, 9, and 10 were screened for in vitro cytotoxic activity against two tumor human cell lines, MCF7 (breast adenocarcinoma) and HepG2 (hepatocellular carcinoma), and for antimicrobial activity against five bacterial species including Gram-positive, Gram-negative, and Mycobacteria strains. Both the IC₅₀ and MIC values revealed excellent biological activity for these metal complexes, compared with their precursors and cisplatin and also AgNO₃ and silver sulfadiazine, respectively. Both IC₅₀ and MIC values are among the lowest values found for any silver derivatives against the cell lines and bacterial strains used in this work. The structure-activity relationships were clear. The most cytotoxic and antimicrobial derivatives were those with the triphenylphosphane and [N₃P₃(NHCy)₆] ligands. A significant improvement in the activity was also observed upon a rise in the number of silver atoms linked to the phosphazene ring.

Ferrocenyl Phosphorhydrazone Dendrimers Synthesis, and Electrochemical and Catalytic Properties

The discovery of ferrocene is often associated with the rapid growth of organometallic chemistry. Dendrimers are highly branched macromolecules that can be functionalized at will at all levels of their structure. The functionalization of dendrimers with ferrocene derivatives can be carried out easily as terminal functions on the surface, but also at the core, or at one or several layers inside the structure. This review will focus on phosphorhydrazone dendrimers functionalized with ferrocene derivatives, on the surface, at the core, at all layers or within a single layer inside the structure. The first part will describe the synthesis; the second part will concern the electrochemical properties; and the last part will give several examples concerning catalysis, with complexes of ferrocenyl phosphines used as terminal functions of dendrimers.

Phosphazene based star-branched polymeric cathode materials via inverse vulcanization of sulfur for lithium–sulfur batteries

Novel insoluble star-shaped hexa-branched polymeric materials based on cyclotriphosphazene core are prepared by the inverse vulcanization of sulfur with hexakis(styreneoxy)cyclotriphosphazene and tested as cathode for lithium–sulfur (Li–S) batteries.

Novel Water-Soluble Cyclotriphosphazene-Bodipy Conjugates: Synthesis, Characterization and Photophysical Properties

In the present work, novel water-soluble cyclotriphosphazene derivatives (3b and 4b) were synthesized by 'click' reactions between cyclotriphosphazene derivative with hydrophilic glycol side groups (2) and Bodipy's (3a and 4a). All newly synthesized compounds (2, 3b and 4b) were characterized by fourier-transform infrared (FTIR), mass and NMR spectroscopy techniques and elemental analysis (EA). The photophysical properties of Bodipy substituted novel cyclotriphosphazenes (3a and 4a) were examined via UV-Vis absorption and fluorescence emission spectroscopy inside water and many organic solvents such as acetone, tetrahydrofuran, dichloromethane, dimethyl sulfoxide, etc., and the results were compared with the each other. Graphical Abstract.

Dendrimeric Nanoparticles for Two-Photon Photodynamic Therapy and Imaging: Synthesis, Photophysical Properties, Innocuousness in Daylight and Cytotoxicity under Two-Photon Irradiation in the NIR

The synthesis and the photophysical properties of a new class of fully organic monodisperse nanoparticles for combined two-photon imaging and photodynamic therapy are described. The design of such nanoparticles is based on the covalent immobilization of a dedicated quadrupolar dye that combines excellent two-photon absorbing (2PA) properties, fluorescence and singlet oxygen generation ability, in a phosphorous-based dendrimeric architecture. First, a bifunctional quadrupolar dye bearing two different grafting moieties, a phenol function and an aldehyde function, was synthesized. It was then covalently grafted through its phenol function to a phosphorus-based dendrimer scaffold of generation 1. The remaining aldehyde functions were then used to continue the dendrimer synthesis up to generation 2, introducing finally 24 water-solubilizing triethyleneglycol chains at its periphery. A dendrimer confining 12 photoactive quadrupolar units in its inner scaffold and showing water solubility was thus obtained. Interestingly, the G1 and G2 dendrimers retain some fluorescence as well as significant singlet oxygen production efficiencies while they were found to show very high 2PA cross-sections in a broad range of the NIR biological spectral window. Hydrophilic dendrimer G2 was tested in vitro on breast cancer cells, first in one- and two-photon microscopy, which allowed for visualization of their cell internalization, then in two-photon photodynamic therapy. While being nontoxic in the dark and, more importantly, under exposure to daylight, dendrimer G2 proved to be a very efficient cell-death inducer only under two-photon irradiation in the NIR.

Interfacial complexation driven three-dimensional assembly of cationic phosphorus dendrimers and graphene oxide sheets

High content nitrogen, sulfur and phosphorus heteroatoms assembled in tree-like dendrimers (DG _n ) are confined within the galleries of two-dimensional graphene oxide (GO). The presence of the ternary diethyl-N-ethyl-ammonium groups on the dendrimer peripheries ensures the exfoliation of graphene sheets thereby affording interfacially bridged, three-dimensional heteroatom-enriched graphene-based hybrid nanostructures (DG _n -GO). Dendrimer generation (from 1 to 4) that reflects the bulkiness of these conceived nano-trees impacts increasingly the degree of dispersion-exfoliation and sheet desordering. The long-term stability of these aqueous suspensions associated with their handling flexibility allows uniform accommodation of the resulting hybrid materials as flame-retardants in bioplastics.

Phosphorylated micro- vs. nano-cellulose: a comparative study on their surface functionalisation, growth of titanium-oxo-phosphate clusters and removal of chemical pollutants

Phosphorylation imparts cellulose (amorphous or crystalline) with original surface reactivity to bridge metal oxide clusters and to scavenge for chemicals.

Phosphorus dendrimers functionalised with nitrogen ligands, for catalysis and biology

Phosphorus dendrimers (dendrimers having one phosphorus atom at each branching point) possess versatile properties, depending on the type of their terminal functions.

Constitutional isomers of dendrimer-like pyrene substituted cyclotriphosphazenes: synthesis, theoretical calculations, and use as fluorescence receptors for the detection of explosive nitroaromatics

Two constitutionally isomeric bis-pyrenyl phenol dendrons (4 and 6) and their dendrimer-like cyclotriphosphazene derivatives (5 and 7) are designed, synthesized and fluorescence detection behaviors are evaluated for nitro aromatic compounds (NACs).

Bench-to-bedside translation of dendrimers: Reality or utopia? A concise analysis

Nanomedicine, which is an application of nanotechnologies in healthcare is developed to improve the treatments and lives of patients suffering from a range of disorders and to increase the successes of drug candidates. Within the nanotechnology universe, the remarkable unique and tunable properties of dendrimers have made them promising tools for diverse biomedical applications such as drug delivery, gene therapy and diagnostic. Up-to-date, very few dendrimers has yet gained regulatory approval for systemic administration, why? In this critical review, we briefly focus on the list of desired basic dendrimer requirements for decision-making purpose by the scientists (go/no-go decision), in early development stages, to become clinical candidates, and to move towards Investigational New Drugs (IND) application submission. In addition, the successful translation between research and clinic should be performed by the implementation of a simple roadmap to jump the 'valley of death' successfully.

Effect of Dendrimer Generation and Aglyconic Linkers on the Binding Properties of Mannosylated Dendrimers Prepared by a Combined Convergent and Onion Peel Approach

An efficient study of carbohydrate-protein interactions was achieved using multivalent glycodendrimer library. Different dendrimers with varied peripheral sugar densities and linkers provided an arsenal of potential novel therapeutic agents that could be useful for better specific action and greater binding affinities against their cognate protein receptors. Highly effective click chemistry represents the basic method used for the synthesis of mannosylated dendrimers. To this end, we used propargylated scaffolds of varying sugar densities ranging from 2 to 18 for the attachment of azido mannopyranoside derivatives using copper catalyzed click cycloaddition. Mannopyranosides with short and pegylated aglycones were used to evaluate their effects on the kinetics of binding. The mannosylated dendrons were built using varied scaffolds toward the accelerated and combined "onion peel" strategy These carbohydrates have been designed to fight E. coli urinary infections, by inhibiting the formation of bacterial biofilms, thus neutralizing the adhesion of FimH type 1 lectin present at the tip of their fimbriae against the natural multiantennary oligomannosides of uroplakin 1a receptors expressed on uroepithelial tissues. Preliminary DLS studies of the mannosylated dendrimers to cross- link the leguminous lectin Con A used as a model showed their high potency as candidates to fight the E. coli adhesion and biofilm formation.

New hexa-bodipy functionalized dendrimeric cyclotriphosphazene conjugates as highly selective and sensitive fluorescent chemosensor for Co2+ ions

In the study, the new hexa-bodipy functionalized dendrimeric cyclotriphosphazene conjugates (HBCP 1 and 2) have been successfully synthesized and characterized by using general spectroscopic techniques such as ¹H, ¹³C and ³¹P NMR spectroscopies. The photophysical and metal sensing properties in THF solutions of dendrimeric cyclotriphosphazene conjugates (HBCP 1 and 2) were investigated by UV-Vis and fluorescence spectroscopies in dilute tetrahydrofuran solutions. These dendrimers showed strong absorption bands 501 and 641nm at low concentration with high molar extinction coefficients. In addition, the stoichiometry of the complex between the conjugate (HBCP 2) and Co²⁺ ions were determined by a Job's plot obtained from fluorescence titrations. The metal sensing data showed that the hexa-bodipy functionalized dendrimeric cyclotriphosphazene conjugate (HBCP 2) is a candidate for fluorescent chemosensor for Co²⁺ ions due to showing high selectivity with a low limit of detection.

Cyclotriphosphazene core-based dendrimers for biomedical applications: an update on recent advances

This review is focused on the recent use of cyclotriphosphazene-based dendrimers in biomedicine. Since its synthesis for the first time in 1834, cyclotriphosphazene has been an important compound of phosphorus chemistry as a scaffold, and a large number of cyclotriphosphazene derivatives have been synthesized and applied in various fields such as biology, catalysis, fluorescence, nanomaterials, etc. Today, one of the most important uses concerns its biomedical applications. In this review, the recent developments (since 2012) of cyclotriphosphazene for major pharmaceutical applications are highlighted and analyzed.

Dendrimers in combination with natural products and analogues as anti-cancer agents

For the first time, an overview of dendrimers in combination with natural products and analogues as anti-cancer agents is presented. This reflects the development of drug delivery systems, such as dendrimers, to tackle cancers. The most significant advantages of using dendrimers in nanomedicine are their high biocompatibility, good water solubility, and their entry - with or without encapsulated, complexed or conjugated drugs - through an endocytosis process. This strategy has accelerated over the years in order to develop nanosystems as nanocarriers, to decrease the intrinsic toxicity of anti-cancer agents, to decrease the drug side effects, to increase the efficacy of the treatment, and consequently to improve patient compliance.

Dendrimers in combination with natural products and analogues as anti-cancer agents

Overview of the use of dendrimers in combination with encapsulated and conjugated natural products and analogues as anti-cancer agents.

A library of multisubstituted cyclotriphosphazenes – molecular scaffolds for hybrid materials

An easy pathway for the synthesis of new cyclotriphosphazene derivatives based on a Pt-catalyzed hydrosilylation process and their characterization are presented.

Dendrimers in combination with natural products and analogues as anti-cancer agents

Overview of the use of dendrimers in combination with encapsulated and conjugated natural products and analogues as anti-cancer agents.

Synergistic Effects between Doped Nitrogen and Phosphorus in Metal-Free Cathode for Zinc-Air Battery from Covalent Organic Frameworks Coated CNT

A covalent organic framework that is composed of hexachlorocyclotriphosphazene and dicyanamide has been coated on CNT to prepare metal-free oxygen reduction reaction catalyst through thermal polymerization of the Zn-air battery cathode. The N,P-codoped nanohybrids have highly porous structure and active synergistic effect between graphitic-N and -P, which promoted the electrocatalytic performance. The electrocatalysts exhibits remarkable half-wave potential (-0.162 V), high current density (6.1 mA/cm^-2), good stability (83%), and excellent methanol tolerance for ORR in alkaline solution. Furthermore, the N,P-codoped nanohybrids were used as an air electrode for fabrication of a high performance Zn-air battery. The battery achieves a high open-circuit potential (1.53 V) and peak power density (0.255 W cm^-2). Moreover, the effect of N,P codoping on the conjugate carbon system and the synergistic effect between graphitic-N and P have been calculated through density functional theory calculations, which are essentially in agreement with experimental data.

Dendrimers, Carotenoids, and Monoclonal Antibodies

Dendrimers are unimolecular architectural nano- or microparticle entities that can accommodate various nutraceuticals and pharmaceuticals between their branches (dendrons) and provide targeted delivery of biomimetics into different tissues upon addition of functionalized groups to the dendrimer's surface. Covalent binding, hydrogen bonds, and electrostatic interactions between dendrimer-composing molecules are known to form and stabilize dendrimer structure. Carotenoids have recently been shown to form dendrimer-like structures and promote targeted delivery of "cargo" molecules into organs characterized by high-carotenoid uptake (adrenal glands, prostate, liver, and brain). The use of carotenoid dendrimers, in particular lycosome particles loaded with various xenobiotics (resveratrol, cocoa flavanols, and HMG-CoA reductase inhibitors), reportedly has a beneficial effect in diabetic foot syndrome, prehypertension, and cardiovascular disease. New applications for carotenoid dendrimers may arise from the use of complexes formed by carotenoid dendrimers and monoclonal antibodies (mAbs). The internalization of carotenoid dendrimer-mAb complexes through receptor-mediated mechanisms may prevent interactions of dendrimer-incorporated xenobiotics with membrane-associated P-glycoprotein, a major factor of drug resistance in tumor cells. The incorporation of mAb fragments with higher binding capacity to the membrane receptors and higher affinity to the target molecule may further increase the bioavailability of "cargo" molecules transported by the carotenoid dendrimer-mAb complexes and open new doors in nanodelivery technologies.