Elif Şenkuytu

Novel Coumarin Substituted Water Soluble Cyclophosphazenes as “Turn-Off” Type Fluorescence Chemosensors for Detection of Fe 3+ ions in Aqueous Media

In the present work, 3-[2-(diethylamino)ethyl]-7-oxy-4-methylcoumarin substituted cyclotriphosphazene (4) and cyclotetraphosphazene (5) derivatives were synthesized by the reactions of hexachlorocyclotriphosphazene (1) or octachlorocyclotetraphosphazene (2) with 3-[2-(diethylamino)ethyl]-7-hydroxy-4-methylcoumarin (3) for the first time. The quaternized cationic (6 and 7) and zwitterionic (8 and 9) derivatives of these compounds (4 and 5) were obtained by the reactions of dimethyl sulfate and 1,3-propanesultone, respectively. All newly synthesized cyclophosphazene compounds (4–9) were fully characterized by elemental analysis and general spectroscopic techniques such as FT-IR, 31P-NMR, 1H-NMR and MALDI-TOF mass. All these coumarin substituted cyclophosphazene compounds (4–9) were soluble in most of organic solvents and quaternized ionic and zwitterionic compounds (6–9) also showed excellent solubility in water. The fluorescence behaviors of novel cyclophosphazene compounds were investigated in methanol and water solutions. The chemosensor properties of newly synthesized water soluble quaternized ionic and zwitterionic cyclotriphosphazene and cyclotetraphosphazene derivatives (6–9) were investigated in aqueous media. These cyclophosphazene derivatives showed fluorescence chemosensor behavior with high selectivity for Fe3+ ions in aqueous solution.

First paraben substituted cyclotetraphosphazene compounds and DNA interaction analysis with a new automated biosensor.

Cancer, as one of the leading causes of death in the world, is caused by malignant cell division and growth that depends on rapid DNA replication. To develop anti-cancer drugs this feature of cancer could be exploited by utilizing DNA-damaging molecules. To achieve this, the paraben substituted cyclotetraphosphazene compounds have been synthesized for the first time and their effect on DNA (genotoxicity) has been investigated. The conventional genotoxicity testing methods are laborious, take time and are expensive. Biosensor based assays provide an alternative to investigate this drug/compound DNA interactions. Here for the first time, a new, easy and rapid screening method has been used to investigate the DNA damage, which is based on an automated biosensor device that relies on the real-time electrochemical profiling (REP™) technology. Using both the biosensor based screening method and the in vitro biological assay, the compounds 9 and 11 (propyl and benzyl substituted cyclotetraphosphazene compounds, respectively), have resulted in higher DNA damage than the others with 65% and 80% activity reduction, respectively.

BODIPY decorated dendrimeric cyclotriphosphazene photosensitizers: synthesis and efficient singlet oxygen generators

In the present work, syntheses of BODIPY decorated dendrimeric cyclotriphosphazenes (8–10) are described. The newly synthesized dendrimeric cyclotriphosphazenes have been characterized by 1H, 13C, 31P NMR spectroscopies, and UV-Vis electronic absorption spectra. These derivatives show absorption in the NIR region with good molar extinction coefficients. Singlet oxygen generation capacities of novel compounds (8–10) are measured using the trap molecule 1,3-diphenylisobenzofuran. BODIPY decorated dendrimeric cyclotriphosphazenes (8–10) demonstrate high singlet oxygen quantum yields. Also, each of them shows chemical and photostability under the conditions of singlet oxygen measurement. The dendrimeric cyclotriphosphazenes are proposed as potential photosensitizers that can be used as efficient singlet oxygen generators.

Structural and fluorescence properties of phenolphthalein bridged cyclotriphosphazatrienes

This study dealt with the reactions of hexachlorocyclotriphosphazatriene, N(3)P(3)Cl(6) (trimer) (1) with phenolphthalein (2) to give the phenolphthalein bridged compounds 3, 4 and 5. The phenolphthalein bridged cyclotriphosphazatriene derivatives are reported for the first time. The new compounds (3-5) are characterized by elemental analysis, mass spectrometry, UV-vis, FT-IR, (1)H, (31)P NMR and fluorescence spectroscopy. The more bridged phenolphthalein groups show the higher intensity of the absorption bands in the UV-vis spectra. Fluorescence spectrum of compound 3 shows a small band in the lower spectral range, while the spectra of compounds 4 and 5 show more intense and a band in higher spectral range.

Octa-BODIPY derivative dendrimeric cyclotetraphosphazenes; photophysical properties and fluorescent chemosensor for Co(2+) ions.

We have designed and synthesized the first examples of fluorescent chemosensors based on octa-BODIPY decorated dendrimeric cyclotetraphosphazenes. The structures these synthesized compounds were verified by 1H, 13C, 31P NMR spectroscopies and UV-vis electronic absorption spectra. The photophysical and metal sensing properties in THF solutions of dendrimeric cyclotetraphosphazenes (OBCP 1-3) were investigated by fluorescence spectroscopy. OBCP 1-3 showed strong absorption in the 500-640nm region with high molar extinction coefficients. Additionally, octa-BODIPY decorated dendrimeric cyclotetraphosphazenes are candidate for fluorescent chemosensor for Co2+ showing high selectivity with a low limit of detection.

Characterization of paraben substituted cyclotriphosphazenes, and a DNA interaction study with a real-time electrochemical profiling based biosensor

AbstractThis paper describes an amperometric method for studying DNA-drug candidate interactions. It uses an automatted electrochemical biosensor (MiSens®) based on real-time electrochemical profiling and gold nanoparticles. A biochip was prepared from a 10 x 20 mm silicon dioxide wafer. The biochip surface is modified with a self-assembled monolayer and integrated into the microfluidic system. All the steps of the DNA-drug interaction assay have been performed during fluid flow. Biotinylated surface DNA has been captured on a NeutrAvidin -modified biochip surface. Hybridization of the complementary target sequence and biotinylated detection probe to the surface DNA strand was studied with and without the addition of newly synthesised drug candidates. NeutrAvidin and enzyme modified gold nanoparticles were then injected to bind to the biochip surface. The real-time reading of the amperometric response during the substrate injection results in the biosensor signal. The DNA interaction analysis was exemplarily applied to test the activity of paraben-substituted cyclotriphosphazenes as potential anticancer agents. Two of the synthesised compounds were identified that are capable of inducing DNA damage by 27 and 34%, respectively. Graphical abstractDNA-drug interactions can be investigated by an automated biosensor device that relies on Real-time Electrochemical Profiling (REP™).

Novel fully-BODIPY functionalized cyclotetraphosphazene photosensitizers having high singlet oxygen quantum yields

Abstract Novel fully-BODIPY functionalized dendrimeric cyclotetraphosphazenes (FBCP 1 and 2) have been synthesized and characterized by 1H, 13C and 31P NMR spectroscopies. The photophysical and photochemical properties of FBCP 1 and 2 are investigated in dichloromethane solution. The effectiveness of singlet oxygen generation was measured for FBCP 1 and 2 by UV–Vis spectra monitoring of the solution of 1,3-diphenylisobenzofuran (DPBF), which is a well-known trapping molecule used in detection of singlet oxygen. FBCP 1 and 2 show high molar extinction coefficients in the NIR region, good singlet oxygen quantum yields and appropriate photo degradation. The data presented in the work indicate that the dendrimeric cyclotetraphosphazenes are effective singlet oxygen photosensitizers that might be used for various areas of applications such as photodynamic therapy and photocatalysis.

Study on the Synthesis, Photophysical Properties and Singlet Oxygen Generation Behavior of Bodipy-Functionalized Cyclotriphosphazenes.

A new series of bodipy-functionalized cyclotriphosphazene derivatives were designed and synthesized. The identities of all newly synthesized compounds were confirmed by using 1H, 13C, 31P NMR spectroscopies. The photophysical properties of bodipy-functionalized cyclotriphosphazenes were investigated via absorption and fluorescense spectroscopies in dichloromethane. Singlet oxygen generation capacities of new compounds were also examined using the trap molecule 1,3-diphenylisobenzofuran. The targeted compounds showed high molar extinction coefficients in the NIR region and respectable singlet oxygen quantum yields when compared to that of methylene blue. The new bodipy-functionalized cyclotriphosphazenes are efficient photosensitizers to be potentially used for the singlet oxygen generation.

Silver(I) coordination polymers assembled from flexible cyclotriphosphazene ligand: structures, topologies and investigation of the counteranion effects.

The reactions of a flexible ligand hexakis(3-pyridyloxy)cyclotriphosphazene (HPCP) with a variety of silver(I) salts (AgX; X = NO3(-), PF6(-), ClO4(-), CH3PhSO3(-), BF4(-) and CF3SO3(-)) afforded six silver(I) coordination polymers, namely {[Ag2(HPCP)]·(NO3)2·H2O}n (1), {[Ag2(HPCP)(CH3CN)]·(PF6)2}n (2), {[Ag2(HPCP)(CH3CN)]·(ClO4)2}n (3), [Ag3(HPCP)(CH3PhSO3)3]n (4), [Ag2(HPCP)(CH3CN)(BF4)2]n (5) and {[Ag(HPCP)]·(CF3SO3)}n (6). All of the isolated crystalline compounds were structurally determined by X-ray crystallography. Changing the counteranions in the reactions, which were conducted under similar conditions of M/L ratio (1:1), temperature and solvent, resulted in structures with different types of topologies. In complexes (1)-(6), the ligand HPCP shows different coordination modes with Ag(I) ions giving two-dimensional layered structures and three-dimensional frameworks with different topologies. Complex (1) displays a new three-dimensional framework adopting a (3,3,6)-connected 3-nodal net with point symbol {4.6(2)}2{4(2).6(10).8(3)}. Complexes (2) and (3) are isomorphous and have a two-dimensional layered structure showing the same 3,6L60 topology with point symbol {4.2(6)}2{4(8).6(6).8}. Complex (4) is a two-dimensional structure incorporating short Ag...Ag argentophilic interactions and has a uninodal 4-connected sql/Shubnikov tetragonal plane net with {4(4).6(2)} topology. Complex (5) exhibits a novel three-dimensional framework and more suprisingly contains twofold interpenetrated honeycomb-like networks, in which the single net has a trinodal (2,3,5)-connected 3-nodal net with point symbol {6(3).8(6).12}{6(3)}{8}. Complex (6) crystallizes in a trigonal crystal system with the space group R\bar 3 and possesses a three-dimensional polymeric structure showing a binodal (4,6)-connected fsh net with the point symbol (4(3).6(3))2.(4(6).6(6).8(3)). The effect of the counteranions on the formation of coordination polymers is discussed in this study.

New hexa-bodipy functionalized dendrimeric cyclotriphosphazene conjugates as highly selective and sensitive fluorescent chemosensor for Co 2+ 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 Jobs 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.