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2-BENZO[C]CINNOLINE AND 2-BENZO[C]CINNOLINE 6-OXIDE MODIFIED GLASSY CARBON ELECTRODES: ELECTROCATALYTIC REDUCTION OF DIOXYGEN IN AQUEOUS MEDIA
(Taylor & Francis Inc, 2011) Isbir-Turan, Aybuke A.; Ustundag, Zafer; Kilic, Emine; Guzel, Remziye; Uckan, Oznur; Solak, Ali Osman
Benzo[c]cinnoline (BCC) molecules were electrochemically grafted onto a glassy carbon (GC) surface in nonaqueous media, and the modified surface was characterized using cyclic voltammetry (CV) with redox probes. Blockage of the electron transfer on the modified surface was observed using redox probes. Electrocatalytic effect of 2BCC modified GC (2BCC-GC) electrode surface towards to the electrochemical reduction of dioxygen was also investigated. A mechanistic scheme for the electrochemical catalysis was proposed. To clarify the mechanism of the dioxygen reduction, a less basic film of 2-benzo[c]cinnoline 6-oxide (2BCCNO) molecules was also prepared at the glassy carbon surface. The effect of electrochemical catalysis of dioxygen reduction at the 2BCC-GC surface was compared to that at the 2BCCNO-GC surface.
Analysis of the Nano-Surface of a Modified Glassy Carbon Electrode by Pseudo Phase Plane Method
(Amer Scientific Publishers, 2011) Tenreiro Machado, J. A.; Baleanu, Dumitru; Dinc, Erdal; Solak, Ali Osman; Eksi, Haslet; Guzel, Remziye
This paper presents the Pseudo phase plane (PPP) method for detecting the existence of a nanofilm on the nitroazobenzene-modified glassy carbon electrode (NAB-GC) system. This modified electrode systems and nitroazobenze-nanofilnn were prepared by the electrochemical reduction of diazonium salt of NAB at the glassy carbon electrodes (GCE) in nonaqueous media. The IR spectra of the bare glassy carbon electrodes (GCE), the NAB-GC electrode system and the organic NAB film were recorded. The IR data of the bare GC, NAB-GC and NAB film were categorized into five series consisting of FILM1, GC-NAB1, GC1; FILM2, GC-NAB2, GC2; FILM3, GC-NAB3, GC3 and FILM4, GC-NAB4, GC4 respectively. The PPP approach was applied to each group of the data of unmodified and modified electrode systems with nanofilm. The results provided by PPP method show the existence of the NAB film on the modified GC electrode.
Characterization Approach to Modified Glassy Carbon Electrode-Nanofilm System Within Multidimensional Scaling
(Amer Scientific Publishers, 2011) Tenreiro Machado, J. A.; Baleanu, Dumitru; Dinc, Erdal; Solak, All Osman; Eksi, Haslet; Guzel, Remziye
The aim of this work is to characterize the nanofilm consisting of the benzoic acid-modified glassy carbon (GC) electrode system through multidimensional scaling space analysis. The surface modification is based on the electrochemical reaction between the GC electrode and benzoic acid-diazonium salt (BA-DAS). As a result, the nonofilms regarding the benzoic acid-glassy carbon (BA-GC) electrode surface was obtained. For the analysis of the naonfilm of BC-GC electrode system, the IR spectra of the modified BA-GC electrode surface, GC surface and BA-DAS were recorded in the spectral range of 599.84 - 3996.34 [cm(-1)]. The IR data vectors of the above three forms were processed by the using the multidimensional scaling space approach to demonstrate the existence of a nanofilm on the modified BA-GC electrode system. Two- and three-dimensional MDS profiles obtained by application of multidimensional scaling approach to the data sets {CG1, ... ,CG10}, {BA-GC1, ... ,BA-GC10} and {FILM1, ... ,FILM10} allow a good recognition of the nanofilm on the modified glassy carbon (GC) electrode system.
Determination of Acetaminophen in Commercial Formulations Using Silver Nanostructured Aniline Modified Pencil Graphite Electrode
(Electrochemical Soc Inc, 2013) Guzel, Remziye; Eksi, Haslet; Dinc, Erdal; Solak, Ali Osman
A nanostructured silver-aniline modified pencil electrode obtained by applying experimental design and optimization was developed for the differential pulse stripping voltammetric quantification of acetaminophen in the pharmaceutical products, tablet and syrup. The electrode development process was performed by the modification of PGE with aniline using CV procedure and the reduction of silver nanoparticle on the polyaniline modified PGE. As a result, a new electrode system consisting of a nanostructured silver-polyaniline modified pencil graphite electrode (AgNS-PA-PGE) was obtained to reach a well-defined and higher peak current for the analysis of the related drug. The calibration curve was found linear in the range of 5 x 10(-8)-8 x 10(-7) M for acetaminophen. The validity and applicability of the proposed voltammetric method was tested by analyzing independent validation samples. It was observed that the proposed voltammetric approach for the real tablet and syrup samples gave successful analysis results. (C) 2013 The Electrochemical Society. All rights reserved.
Determination of Trace Elements in Turkish Wines by ICP-OES and HG-ICP-OES
(Atomic Spectroscopy Press Ltd, 2010) Aydin, Isil; Yuksel, Uyan; Guzel, Remziye; Ziyadanogullari, Berrin; Aydin, Firat
The aim of this work was to determine the concentration of toxic metals in wine samples from different regions in Turkey using ICP-OES and HG-ICP-OES, and comparing the results with reports from other researchers. Ten samples each of white wines and red wines were obtained at a local supermarket and analyzed for Ca, K, Cr, Mn, Sn, Zn, Cu, Fe, Ni, Mg, Al, and Co by inductively coupled plasma optical emission spectrometry (ICP-OES), and for Hg, Pb, and Cd by hydride generation combined with inductively coupled plasma optical emission spectrometry (HG-ICP-OES). The concentrations found in red and white wines were, respectively: Cd: 0.017 and 0.016 mu g L-1; Ply 0.021 and 0.030 mu g L-1; Hg: <0.005 and <0.01 mu g L-1; Ca: 44.118 and 42.195 mg L-1, Cr: 0.056 and 0.0584 mg L--1,L- K: 1169 and 986 mg L--1,L- Mn: 1.564 and 0.118 mg L--1,L- Sn: 0.098 and 0.089 mg L--1,L- Zn: 0.665 and 0.473 mg L-1, Cu: 0.079 and 0.126 mg L-1, Fe: 1.024 and 1.005 mg L-1, Ni: 0.036 and 0.051 mg L-1, Mg: 78 and 68 mg L-1, Al: 0.524 and 0.524 mg L-1, Co: 0.214 and 0.134 mg L-1, The accuracy of the method was verified using the standard reference material NRCSLRS-4 River Water. The analytical values obtained are comparable with those reported by other researchers.
Effect of Au and Au@Ag core-shell nanoparticles on the SERS of bridging organic molecules
(Academic Press Inc Elsevier Science, 2010) Guzel, Remziye; Ustundag, Zafer; Eksi, Haslet; Keskin, Selda; Taner, Bilge; Durgun, Zeynep Gulsah; Turan, Aybuke A. Isbir
Gold nanoparticles (AuNPs) with about 6 nm size were produced and stabilized with mercaptopropionic acid (MPA) film to produce a monolayer protected cluster (MPC) of AuS(CH2)(2)COOH. 4-Aminothiophenol (ATP) molecules were introduced to the activated carboxylic acid ends of the film surrounding the AuNPs to produce AuS(CH2)(2)CONHPhSH MPC. These modified AuNPs were again self-assembled with Au@Ag core-shell bimetallic nanoparticles via the -SH groups to produce an organic bridge between Au and Au@Ag metallic nanoparticles. An unusually strong enhancement of the Raman signals was observed and assigned to the plasmon coupling between the AuNPs and Au@Ag NPs bridged assembly. Formation of AuS(CH2)(2)COOH and AuS(CH2)(2)CONHPhSH clusters and AuS(CH2)(2)CONHPhS(Au@Ag) assembly is confirmed by UV-Vis, reflection-absorption IR spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS), as well as by TEM analysis. The SERS activity of the AuNPs and Au@Ag NPs was tested using the HS(CH2)(2)CONHPhSH molecule as a probe to compare the effectiveness of monometallic and bimetallic systems. SERS spectra show that Au@Ag bimetallic nanoparticles are very effective SERS-active substrates. (C) 2010 Elsevier Inc. All rights reserved.
Factor Analysis for the Characterization of the Nano-Surface of the Nitroazobenzene-Modified Glassy Carbon Electrode
(Amer Scientific Publishers, 2012) Dinc, Erdal; Baleanu, Dumitru; Solak, Ali Osman; Eksi, Haslet; Guzel, Remziye
Factor analysis with orthogonal varimax rotation was applied to determine the existence of a nano-structure on the nitroazobenze-modified glassy carbon electrode (NAB-GC) system. The NAB-GC electrode systems and benzoic acid-nanofilm (NAB-FILM) were obtained by using the electrochemical surface modification experiments. The IR spectra of the bare glassy carbon electrodes (GC), the NAB-GC electrode system and NAB-FILM were recorded. The IR data of the bare GC, BA-GC and BA-FILM were categorized into five series consisting of FILM1, GC-NAB1, GC1; FILM2, GC-NAB2, GC2; FILM3, GC-NAB3, GC3; FILM4, GC-NAB4, GC4; FILM5, GC-NAB5, GC5, respectively. The factor loadings were extracted by making use of the factor analysis approach applied to each group. The orthogonal varimax rotation technique was used to obtain the rotated factor loadings corresponding to the first two factors. After the estimation of the relationship among and within groups, the results predict the existence of the NAB-FILM on the NAB modified glassy carbon electrodes.
Ferritin based bionanocages as novel biomemory device concept
(Elsevier Advanced Technology, 2018) Elmas, Sukriye Nihan Karuk; Guzel, Remziye; Say, Mehmet Girayhan; Ersoz, Arzu; Say, Ridvan
Ferritin is an iron cage having protein, capable of extracting metal ions in their cages and a consequence of the electron transfer of metal ions in their cage by reduction and oxidation processes, electrochemical information storage devices can be designed. In this work, ferritin based protein biomemory substrate has been synthesized by using Amino Acid (monomer) Decorated and Light Underpinning Conjugation Approach (ANADOLUCA) method, which utilizes photosensitive electron transfer based microemulsion co-polymerization as nanobead form of ferritin. Protein substrate contains metal ions such as silver and copper or metal ion pairs namely, silver copper (Janus bionanocage) and co-polymeric shell of the photosensitive crosslinker protein. The redox behavior of bionanocages differentiates electrochemical writing and erase states depending on these metal ions (silver or copper) or metal ion pairs. The bionanocages based biomemory substrates have been immobilized using graphene modified glassy carbon electrodes and the memory functions of ferritin based bionanocages have been confirmed by chronoamperometry (CA) and open circuit potential amperometry (OCPA). The stability and durability of multi-state memory devices represent promising properties for future bioelectronic information technologies.
Half-sandwich ruthenium(II) and iridium(III) complexes of imidazole based phosphinite ligands: antioxidant and antibacterial activities as well as electrochemical properties
(Wiley-V C H Verlag Gmbh, 2024) Isik, Ugur; Rafikova, Khadichakhan; Meric, Nermin; Guzel, Remziye; Kerimkulova, Aygul; Akimbek, Arailym; Okumus, Veysi
Ruthenium(II) and iridium(III) complexes of phosphinites including imidazole moiety were synthesized and characterized by microanalysis, IR, MS, and NMR spectroscopies. Antibacterial activity against Gram-positive and Gram-negative bacterial strains was assessed in all complexes. The highest radical scavenging (72.2 %) was obtained for [3-(3-chloro-2-({[dichloro(eta 6-benzene)ruthenium]diphenylphosphanyl}oxy)propyl)-1-butyl-1H-imidazol-3-ium chloride], 4 at 200 mu g/mL concentration, while [3-(3-chloro-2-({[dichloro(eta 5-pentamethylcyclopentadienyl)-iridium]diphenylphosphanyl}oxy)pro-pyl)-1-butyl-1H-imidazol-3-ium chloride], 6 demonstrated the highest antibacterial activity as 13 mm inhibition zone against E. hirea. Furthermore, optical and electrochemical featured of metal complexes containing imidazole phosphinite were investigated utilizing UV-vis absorption and cyclic voltammetry techniques. Consequently, all complexes can be proposed as metal-based charge convertible phosphinite complexes which may be employed as new generation and synergistic Dye-Sensitized Solar Cell (DSSC) materials. Ruthenium(II) and iridium(III) complexes of phosphinites including imidazole moiety are synthesized and characterized by microanalysis, IR, MS, and NMR spectroscopies. Their antibacterial activity against Gram-positive and Gram-negative bacterial strains is assessed. Furthermore, optical and electrochemical features of the metal complexes are investigated utilizing UV-vis absorption and cyclic voltammetry techniques. image
Light harvesting and photo-induced electrochemical devices based on bionanocage proteins
(Elsevier, 2019) Guzel, Remziye; Ocak, Yusuf Selim; Karuk, Sukriye Nihan; Ersoz, Arzu; Say, Ridvan
In this study, bionanoferritin based Fe and Mn having nanocages, FeMnFBNC's, have adsorbed onto the immobilized graphene surface by electrostatic bonding. This immobilization enhances the capability of electron transfer between the bionanoferritin layer and graphene surface owing to the well-designed robust bionanocage structure. FeMnFBNCs have electronic bridges that consist of some tyrosine and ferritin amino acid residues with visible light photocrosslinking system between iron and manganese metals, which are capable of electron transfer that allows designing electrochemical and energy harvesting devices. Additionally, a novel hybrid and self-assembly bio-dye-approach as a new generation of dye-sensitized solar cells has been developed. Bio-nanoferritin/graphene/TiO2 based Bio-N-DSSC molecules can provide an intriguing alternative to traditional materials utilized in dye-sensitized solar cells.
Multistate proteinous biomemory device based on redox controllable hapten cross-linker
(Elsevier, 2017) Guzel, Remziye; Ersoz, Arzu; Dolak, Ibrahim; Say, Ridvan
A multistate biomemory device consisting of cytochrome c (Cyt-c) photosensitively cross-linked by MACysRu(bipyr)(2)-MACys hapten molecules, which have memory effect through a charge transfer mechanism, has been developed. In this study, it has suggested a highly resolute surface-confined switch composed a signal-enhanced electro-active protein (Cyt-c) co-polymerized on the gold substrates that can be controlled by redox property through Ruthenium based cysteine monomer hapten, MACys-Ru(bipyr)(2)-MACys as an ANADOLUCA photosensitive cross-linker. The photosensitive cross-linking of the Cyt-c protein on the gold surface topography has been determined by the scanning electron microscopy (SEM). Two state memory functions, writing and erasing of the developed biomemory device, have been investigated by the chronoamperometry (CA) and open-circuit potential amperometry (OCPA). The polymeric proteinous memory device, p(MACys-Ru(bipyr)(2)-MACys-coCyt-c) layer, on the gold electrode is stable and repeatable up to with 10(4) times continuous cycle. (C) 2017 Elsevier B.V. All rights reserved.
Nano-hemoglobin film based sextet state biomemory device by cross-linked photosensitive hapten monomer
(Elsevier Science Bv, 2018) Guzel, Remziye; Ersoz, Arzu; Ziyadanogullari, Recep; Say, Ridvan
In this study, a biomemory device, consisting of hemoglobin (Hb) cross-linked by MACys-Ru(bipyr)(2)-MACys) photosensitive monomer cross-linkers, which have memory effect through both Ru3+/2+ in hapten monomer and Fe3+/2+ in redox active center of Hb through multi-charge transfer mechanism, has been improved. Cyclic voltammetry (CV) has been used to determine the redox property of the Hb cross-linked MACys-Ru(bipyr)(2)-MACys) hapten. Three memory functions, writing, reading and erasing of the fabricated biomemory device, have been accomplished by chronoamperometry (CA) and open-circuit potential amperometry (OCPA). The reliability and repeatability of the biodevice consisting of the p(Hb-co-MACys-Ru(bipyr)(2)-MACys) sextet state bio-memory layer have been analysed. The Hb film based biodevice on gold electrodes has shown >= 2 months the retention time and switched until 10(6) times continuous cycling without degradation in efficiency. Other hand, the topography of p(Hb-co-MACys-Ru(bipyr)(2)-MACys) layer on the gold surface has investigated by scanning electron microscopy (SEM) and EDX data.
A new approach to the characterization of the nano-surface structure by using factor analysis
(Elsevier, 2012) Dinc, Erdal; Baleanu, Dumitru; Solak, Ali Osman; Eksi, Haslet; Guzel, Remziye
The study provides a new approach to explore the existence of a nanostructure on the benzoic acid-modified glassy carbon electrode (BA-GC) system by applying factor analysis with varimax rotation of factors. The infrared spectra (IR) spectra of the bare glassy carbon electrodes (GC) and the BA-GC electrode systems with benzoic acid-nanofilm (BA-FILM) were obtained by using 10 different surface modification experiments. The IR data of the bare GC, BA-GC and BA-FILM were categorized into three series corresponding to the GC, BA-GC and BA-FILM. The factor analysis method was separately applied to each group to extract the factor loadings. By making use of these loadings, the rotated factor loadings corresponding to the first two factors were computed to estimate the relationship among and within groups. The results provided by the factor analysis method indicate the existence of the BA-FILM on the BA modified glassy carbon electrode. (C) 2011 Elsevier B.V. All rights reserved.
A New UPLC Approach for the Simultaneous Quantitative Estimation of Four Compounds in a Cough Syrup Formulation
(Oxford Univ Press Inc, 2016) Turak, Fatma; Guzel, Remziye; Dinc, Erdal
A new ultra-performance liquid chromatographic (UPLC) method was developed for the simultaneous estimation of potassium guaiacolsulfonate (PGS), guaifenesin (GUA), diphenhydramine HCl (DIP) and carbepentane citrate (CAR) in a commercial cough syrup. The chromatographic separation of four compounds PGS, GUA, DIP and CAR was performed on a BEH phenyl column (100 x 2.1 mm, 1.7 mu m i.d.) using a mobile phase consisting of acetonitrile and 0.1 MHCl (50 : 50, v/v). In addition, the optimized conditions of the chromatographic analysis were found with the flow rate of 0.38 mL/min, the column temperature of 30 degrees C and the injection volume of 1.2 mu L with the photodiode array detection of 220 nm. Calibration curves in the concentration ranges of 10-98 mu g/mL for PGS, 5-80 mu g/mL for GUA, 5-25 mu g/mL for DIP and CAR were computed by the regression of the analyte concentration on the chromatographic peak area. The newly developed UPLC method was validated by analyzing the quaternary mixtures of the related compounds, intraday and interday experiment and standard addition samples. After method validation, the proposed UPLC approach was successfully applied for the analysis of the commercial syrup formulation containing PGS, GUA, DIP and CAR compounds.
New Voltammetric Approach to the Quantitation of Paracetamol in Tablets and Syrup using Chemometric Optimization Technique
(Pleiades Publishing Inc, 2019) Guzel, Remziye; Eksi, Haslet; Dinc, Erdal; Solak, Ali Osman
A new voltammetric approach was developed for the determination of paracetamol in tablet and syrup samples using chemometric optimization. The method is based on the use of the gold nanoparticles-polyaniline (AuNPs-PA) modified pencil graphite electrode (PGE). Electrode system was fabricated by using the electrochemical reduction of gold on aniline modified pencil electrode to give gold nanoparticles. A 3(3) full factorial design was used to find optimal oxidation conditions of paracetamol on the AuNPs-PA-PGE. The optimal oxidation conditions of drug substance were found as -524 mV for the accumulation potential, 295 s for the accumulation time and pH 8.69 (for the phosphate buffer solution, 0.1 M). The determination of paracetamol was linear in the range of 2.0 x 10(-7)-6.0 x 10(-6) M with a detection limit of 5 x 10(-8) M. As a result, the proposed voltammetric approach gave satisfactory results for the determination of the related drug substance in tablets and syrup.
A novel surface plasmon resonance enhanced total internal reflection ellipsometric application: electrochemically grafted isophthalic acid nanofilm on gold surface
(Royal Soc Chemistry, 2011) Ustundag, Zafer; Caglayan, Mustafa Oguzhan; Guzel, Remziye; Piskin, Erhan; Solak, Ali Osman
The scope of this study is to modify a Surface Plasmon Resonance (SPR) sensor slide with isophthalic acid to evaluate the possible application on the detection of copper(II) ions in aqueous media by total internal reflection ellipsometry. A gold sensor surface was modified by an electrochemical diazonium reduction modification method. The modified surfaces are characterized with cyclic voltammetry (CV) and ellipsometry. Isophthalic acid monolayer modified gold slides were used for in situ detection of aqueous Cu2+ solution with the SPR enhanced total internal reflection ellipsometry (SPRe-TIRE) technique. Layer formation, pH dependency of adsorption, sensor response of the SPRe-TIRE and isothermal kinetic parameters were examined. A high dependency on the number of CV cycles in the monolayer-multiple layer transition was observed. The suggested sensor gave a linear response over a wide range of Cu2+ concentrations. It was also reported that adsorption on the SPRe-TIRE sensor gave Langmuir adsorption model behavior.
Phosphorus-nitrogen compounds. Part 65. Novel diansa-spiro-cyclotetraphosphazenes: synthesis, characterization, bioactivity and electrochemical properties, and dye-sensitized solar cell fabrication studies
(Royal Soc Chemistry, 2022) Mutlu, Gurcu; Okumus, Aytug; Elmas, Gamze; Kilic, Zeynel; Guzel, Remziye; Sabah, Busra Nur; Acik, Leyla
In this investigation, the substitution reaction of octachlorocyclotetraphosphazene, N4P4Cl8 (tetramer, OCCP, 1), with sodium 3-(N-ferrocenylmethylamino)-1-propanoxide (L1) was found to yield the compounds, 2,4-ansa-(2) and spiro-(2) cyclotetraphosphazene derivatives. The starting hexachloro-2-cis-4-dichloro-monoferrocenyl-ansa-(N/O)cyclotetraphosphazene (2) reacted separately with dipotassium salts of N2O2 donor-type aminopodands, (KOPhCH2NH)(2)R [R = (CH2)(n), n = 2 (L2) and n = 3 (L3)], to produce mono-ferrocenyl-2,4-ansa-6,8-ansa-spirocyclotetraphosphazenes (dias; 3 and 4). Both products were purified by column chromatography, and their structures were confirmed using ESIMS, FTIR, H-1, C-13, and P-31 NMR spectral data. Besides, the molecular and crystal structures of 4 were elucidated by single-crystal X-ray diffraction. Compound 4 has four-different chiral P-centers. However, the absolute configuration of stereogenic P-centres of an enantiomer was designated as SS'S '' R'''. Both new compounds were also used for the examination of optical and electrochemical properties, and survey of bioactivity. To this end, the minimum inhibitory, bactericidal, and fungicidal concentrations (MIC, MBC, and MFC) were determined with the microdilution technique. These MIC, MBC, and MFC values were found to vary between 2500 mu M and 312.5 mu M. DNA cleavage activities of 3 and 4 with pBR322 plasmid DNA were also studied using electrophoretic mobility on an agarose gel. BamHI and HindIII restriction enzyme digestions of compound-pBR322 plasmid DNA were conducted to supply more insight into changes in DNA conformation. Cyclotetraphosphazene 4 caused DNA cleavage activity even at the lowest concentration. In addition to that, compound 4 inhibited enzyme digestion, indicating that DNA binds to A/A nucleotides with DNA binding activity. Moreover, the cytotoxicities of 3 and 4 were investigated by MTT assay against MDA-MB-231 breast cancer cells and COS-1 mammalian fibroblast cells. On the other hand, the optical and electrochemical properties of dias 3 and 4 were studied using UV-vis absorption and cyclic voltammetry techniques. As a result, both compounds can be suggested as ferrocene-based charge transformable phosphazene structures that can be used as new generation and synergistic DSSC materials.
Phosphorus-nitrogen compounds. Part 72. Bisspiro(N/N) cyclotri-phosphazenes with 4-chlorobenzyl and ferrocenyl pendant arms: Synthesis, structural characterization, dye-sensitized solar cell fabrication and antituberculosis activity studies
(Elsevier, 2024) Berberoglu, Ipek; Cemaloglu, Resit; Binici, Arzu; Yakut, Mehtap; Asmafiliz, Nuran; Kilic, Zeynel; Guzel, Remziye
In this study, dichlorobisspiro(N/N)cyclotriphosphazenes with 4-chlorobenzyl and ferrocenyl-pendant arms were prepared to investigate their spectroscopic and crystallographic characterizations, and antituberculosis activities. The chlorine replacement reactions of tetrachloro(4-chlorobenzyl)spiro(N/N)cyclotri-phosphazenes with ferrocenyldiamines (4 and 5) lead to dichlorobispiro(N/N)cyclotriphosphazenes, containing unsymmetrical diaminospirorings. All cyclotriphosphazenes were characterized by mass spectrometry, FTIR and 31P NMR spectroscopies. Two different stereogenic P-centers are present in the unsymmetrically substituted inorganicorganic fused hybrid rings. These compounds may be in the form of racemic mixtures (RR'/SS' and RS'/SR'). The molecular and crystal structures of trans (6a and 7a) and cis (6b and 7b) isomers were elucidated by singlecrystal X-ray structural crystallography. The space groups of trans-6a, cis-6b, trans-7a and cis-7b are centrosymmetric P -1, P bca, P 21/n and P bca, respectively. Therefore, the crystal lattices contain both enantiomers. The absolute configurations of P2 atoms of 6a, 6b, 7a and 7b are R, R, S and S, respectively. It was determined that the most effective compound was 6b against Mycobacterium tuberculosis H37Rv (ATCC 27,294) strain among the phosphazenes 6a, 6b and 10b. Among the compounds, In the reversible cyclic voltammograms of ferrocenyldispirophosphazenes, only one oxidation-reduction wave was observed. The HOMO energy values of the compounds were figured out using the oxidation potential (Eox). Whereas, the LUMO energy values were figured out from the optical band gap values using Tauc plots. In addition, it was determined that the most effective compound that can be used in dye-sensitized solar cells (DSSCs) is cis-11b.
Phosphorus-nitrogen compounds. Part 77. The synthesis of novel ferrocenyl(N/O)spiro- and 2-cis-4-dichloro-ferrocenyl(N/O)ansa-cyclotetraphosphazenes with 9-ethyl-3-carbazolyl pendant arm(s): spectral, bioactivity, electrochemical and dye-sensitized solar cell fabrication studies
(Taylor & Francis Ltd, 2025) Mutlu, Gurcu; Yakut, Mehtap; Okumus, Aytug; Elmas, Gamze; Binici, Arzu; Guzel, Remziye; Sabah, Busra Nur
Herein, the reactions of octachlorocyclotetraphosphazene (OCCP, 1) with sodium-3-ferrocenylmethyl-amino)-1-propanoxide (L1) gave hexachloro-ferrocenyl-(N/O)-spiro-2 and 2-cis-4-dichloro-ferrocenyl-(N/O)-ansa-3 cyclotetraphosphazenes in THF. Spiro- (2) reacted with excess 9-ethyl-N-methyl-3-carbazolyl-1,3-diaminopropane (L2) and 9-ethyl-N-ethyl-3-carbazolyl-1,2-diaminoethane (L3) to produce 2-trans-6-dispiro (dispiro-2a) and 2-trans-4-cis-6-trans-8-tetraspiro (tetraspiro-2b) cyclotetraphosphazenes, respectively. The reactions of ansa-3 with excess L2 led to the formation of monospiro {2-cis-4-dichloro-ansa-2-trans-6-spiro(N/N) (ansa-spiro-3b)} and dispiro {2-cis-4-dichloro-ansa-6-trans-8-dispiro(N/N) (ansa-dispiro-3b)} cyclotetraphosphazenes. However, the reactions of ansa-3 with excess 9-methyl-N-ethyl-3-carbazolyl-1,2-diaminomethane (L4) afforded 2-cis-4-dichloro-ansa-6-trans-8-dispiro(N/N) (ansa-dispiro-3a). Ansa-3 was also reacted with excess sodium 3-(9-ethyl-carbazolamino)-1-propanoxide (L5) to give 2-cis-4-dichloro-ansa-2-trans-6-spiro(N/O) (ansa-spiro-3c) and 2-cis-4-dichloro-ansa-6-trans-8-dispiro(N/O) (ansa-dispiro-3c) cyclotetraphosphazenes. Reactions were carried out by classical and microwave-assisted methods. These novel multi-heterocyclic inorganic/organic hybrid cyclotetraphosphazenes can offer valuable insights into developing new materials. Tetraspiro-2b and all ansa compounds have more than one stereogenic P-atom. The optical and electrochemical properties of some cyclotetraphosphazenes were investigated using UV-vis absorption and cyclic voltammetry (CV) techniques. As a result, these phosphazenes can be suggested as ferrocene-based charge transformable structures. They can be used as new-generation and synergistic dye-sensitized solar cell (DSSC) materials. Additionally, antimicrobial activities of five compounds (dispiro-2a, ansa-spiro-3b, ansa-dispiro-3b, ansa-spiro-3c and ansa-dispiro-3c) against various pathogenic bacteria and yeasts were evaluated. Their interactions with pBR322 plasmid DNA were also investigated.
Phosphorus-nitrogen compounds: Part 60: Synthesis of hexaminomonoferrocenyl-spiro(N/O)cyclotetraphosphazenes: Spectral and electrochemical properties, tuning of redox feature, and antituberculosis activity
(Taylor & Francis Ltd, 2023) Binici, Arzu; Elmas, Gamze; Okumus, Aytug; Guzel, Remziye; Simsek, Hulya; Kilic, Zeynel
In the present investigation, the condensation reaction of octachlorocyclotetraphosphazene, N4P4Cl8 (1) (tetramer, OCCP), with sodium 3-(N-ferrocenylmethylamino)-1-propanoxide (L) resulted in the formation of the starting compound hexachloromonoferrocenylspiro(N/O)cyclotetraphosphazene (2). Thereafter, reactions of spiro (2) with excesses of 1-(2-aminoethyl)pyrrolidine, 1-(2-aminoethyl)piperidine and 4-(2-aminoethyl)morpholine in dry THF gave hexaaminomono-ferrocenylspiro(N/O)cyclotetraphosphazenes, 2a, 2b, and 2c, respectively. These new products were prepared for investigation of spectral and electrochemical properties, tuning of redox features, and examination of antituberculosis activities. The structures of 2a-2c were elucidated using elemental analysis, mass spectrometry (ESI-MS), FTIR, HMBC, HSQC, H-1, C-13 {H-1}, and P-31 {H-1} NMR data. The electrochemical behavior of these products containing monoferrocenyl group was investigated. Their use as potential alternative electrolyte redox couples for dye-sensitized solar cells (DSSC) was examined. The findings may inspire solar cell studies to explore the redox mediator behind the working mechanisms of DSSCs. Conversely, the antituberculosis activities of three compounds were examined against Mycobacterium tuberculosis H37Rv. The MIC values of 2a and 2 b were found to be as 30 and 35 mu g/mL, respectively, against the H37Rv reference strain.

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