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Article Citation - WoS: 34Citation - Scopus: 37Hydroxyapatite-Nanosphere Supported Ruthenium(0) Nanoparticle Catalyst for Hydrogen Generation From Ammonia-Borane Solution: Kinetic Studies for Nanoparticle Formation and Hydrogen Evolution(Royal Soc Chemistry, 2014) Durak, Halil; Gulcan, Mehmet; Zahmakiran, Mehmet; Ozkar, Saim; Kaya, MuratThe development of readily prepared effective heterogeneous catalysts for hydrogen generation from ammonia-borane (AB; NH3BH3) solution under mild conditions still remains a challenge in the field of "hydrogen economy". In this study, we report our finding of an in situ generated, highly active ruthenium nanocatalyst for the dehydrogenation of ammonia-borane in water at room temperature. The new catalyst system consists of ruthenium(0) nanoparticles supported on nanohydroxyapatite (RuNPs@nano-HAp), and can be reproducibly prepared under in situ conditions from the ammonia-borane reduction of Ru3+ ions exchanged into nanohydroxyapatite (Ru3+@nano-HAp) during the hydrolytic dehydrogenation of ammonia-borane at 25 +/- 0.1 degrees C. Nanohydroxyapatite-supported ruthenium(0) nanoparticles were characterized by a combination of advanced analytical techniques. The sum of their results shows the formation of well-dispersed ruthenium(0) nanoparticles with a mean diameter of 2.6 +/- 0.6 nm on the surface of the nanospheres of hydroxyapatite by keeping the host matrix intact. The resulting RuNPs@nano-HAp are highly active catalyst in the hydrolytic dehydrogenation of ammonia-borane with an initial TOF value of 205 min(-1) by generating 3.0 equiv. of H-2 per mole of ammonia-borane at 25 +/- 0.1 degrees C. Moreover, they are sufficiently stable to be isolated and bottled as solid materials, which can be reused as active catalyst under the identical conditions of first run. The work reported here also includes the following results: (i) monitoring the formation kinetics of the in situ generated RuNPs@nano-HAp by hydrogen generation from the hydrolytic dehydrogenation of ammonia-borane as the reporter reaction. The sigmoidal kinetics of catalyst formation and concomitant dehydrogenation fits well to the two-step, slow nucleation, followed by autocatalytic surface growth mechanism, P -> Q (rate constant k(1)) and P + Q -> 2Q (rate constant k(2)), in which P is Ru3+@nano-HAp and Q is the growing, catalytically active RuNPs@nano-HAp; (ii) the compilation of kinetic data for the RuNPs@nano-HAp catalyzed hydrolytic dehydrogenation of ammonia-borane depending on the temperature and catalyst concentration to determine the dependency of reaction rate on catalyst concentration and activation parameters (E-a, Delta H-#, and Delta S-#) of the reaction.Article Citation - WoS: 7Citation - Scopus: 9Pyrrole Coupling Chemistry: Investigation of Electroanalytic, Spectroscopic and Thermal Properties of N-Substituted Poly(bis-Pyrrole) Films(Royal Soc Chemistry, 2013) Mert, Olcay; Demir, Ayhan S.; Cihaner, AtillaAn etheric member of N-linked polybispyrroles (PolybisPy) based on 1-(3-(2-(2-(3-(1H-pyrrol-1-yl)propoxy)ethoxy)ethoxy)propyl)-1H-pyrrole (1) was electrochemically synthesized for the versatile investigation of its exciting electrochromic and ion receptor properties. It has been fully characterized by electroanalytic, spectroscopic, thermal, and four-probe techniques. It was thereby found that P1 shows strong stability, and a reversible redox process as well as a good electrochromic material property; transparent yellow in the neutral state, light pink in the intermediate state, and blue in the oxidized state. Also, the corresponding polymer (P1) exhibited a selective voltammetric response towards Na+ among the alkali series in an organic medium. Moreover, P1 film was employed for the detection of Ag+ ions in the solution with cyclic voltammetry without precipitants or complexing ligands, and SEM images confirmed the deposition of metallic silver on the film surface. These prominent features also make P1 a good candidate for many practical uses, such as the recovery of metals and ion sensors.Article Citation - WoS: 7Citation - Scopus: 7Surface Plasmon Resonance Aptasensor for Soluble Icam-1 Protein in Blood Samples(Royal Soc Chemistry, 2022) Dursun, Ali Dogan; Dogan, Soner; Kavruk, Murat; Tasbasi, B. Busra; Sudagidan, Mert; Yilmaz, M. Deniz; Tuna, Bilge G.Intercellular Adhesion Molecule-1 (ICAM-1) is considered to be a cancer biomarker in the assessment of metastatic potential in patients and an early indicator of atherosclerosis. A labelless biosensor based on the surface plasmon resonance (SPR) signal from the specific affinity interaction of an aptamer and a soluble ICAM-1 protein was developed for blood samples. The developed aptasensor provided real-time information on the concentration of the ICAM-1 protein in blood when integrated to a purification step based on a magnetic pull-down separation. The SPR aptasensor was highly specific with a limit of detection of 1.4/0.2 ng ml(-1), which was achieved through aptamer-functionalized silica-coated magnetic nanoparticles.Article Citation - WoS: 8Citation - Scopus: 8Complex Nodal Structure Phonons Formed by Open and Closed Nodal Lines in Coass and Na2cup Solids(Royal Soc Chemistry, 2022) Ding, Guangqian; Sun, Tingting; Surucu, Gokhan; Surucu, Ozge; Gencer, Aysenur; Wang, XiaotianTopological phononic states with nodal lines not only have updated our knowledge of the phases of matter in a fundamental way, but also have become a major frontier research direction in condensed matter physics. From a mathematical perspective, nodal line phonons can be divided into open and closed types. The present attempt is a report on the coexistence of such open and closed nodal line phonons in two realistic solids, CoAsS and Na2CuP, based on first-principles calculations. Furthermore, it is shown that the closed and the open nodal line states in CoAsS and Na2CuP have touching points and can form a complex nodal structure phonon in a momentum space. Due to the topologically non-trivial behavior of the complex nodal structure in both phonons, evident phononic surface states occur in the projected surfaces of both materials. In this way, these states, arising from the projected crossing points, can benefit experimental detection in follow-up studies. It has been stated that the open and closed nodal line states are formed by the crossings of two phonon branches and, hence, these two types of nodal line phonons are coupled with each other. The results obtained here could be considered as a breakthrough in clearly demonstrating the coexistence of the open and closed nodal line states in phonons and, for this reason, may inspire researchers seeking materials with such topological states in other bosons, such as photons.Article Citation - WoS: 52Citation - Scopus: 59Furan and benzochalcogenodiazole based multichromic polymers via a donor-acceptor approach(Royal Soc Chemistry, 2013) Icli-Ozkut, Merve; Ipek, Halil; Karabay, Baris; Cihaner, Atilla; Onal, Ahmet M.Two new furan and benzochalcogenodiazole based monomers, namely 4,7-di(furan-2-yl) benzo[c][1,2,5]-selenadiazole (FSeF) and 4,7-di(furan-2-yl) benzo[c][1,2,5]thiadiazole (FSF), were designed and synthesized via a donor-acceptor-donor approach. The monomers were electrochemically polymerized via potentiodynamic or potentiostatic methods. The monomers and their polymers exhibited lower oxidation potentials (1.16 V and 1.06 V for monomers; 0.93 V and 0.80 V for polymers vs. Ag/AgCl) and red shifts of the whole dual-band absorption spectra upon moving from S to Se. Intramolecular charge transfer properties of the monomers and the polymers were demonstrated by using electroanalytical and optical methods. Also, the polymers PFSeF and PFSF were multicolored at different redox states and have low band gaps of 1.43 eV and 1.61 eV, respectively.Article Citation - WoS: 7Citation - Scopus: 7Antibiotic administration in targeted nanoparticles protects the faecal microbiota of mice(Royal Soc Chemistry, 2021) Borsa, Baris A.; Sudagidan, Mert; Aldag, Mehmet E.; Baris, Isik I.; Acar, Elif E.; Acuner, Cagatay; Ozalp, Veli C.Antibiotic therapy comes with disturbances on human microbiota, resulting in changes of bacterial communities and thus leading to well-established health problems. In this study, we demonstrated that targeted teicoplanin administration maintains the faecal microbiota composition undisturbed in a mouse model while reaching therapeutic improvements for S. aureus infection.Article Citation - WoS: 13Citation - Scopus: 14Thermally Highly Stable Polyhedral Oligomeric Silsesquioxane (poss)-Sulfur Based Hybrid Inorganic/Organic Polymers: Synthesis, Characterization and Removal of Mercury Ion(Royal Soc Chemistry, 2022) Berk, Hasan; Kaya, Murat; Cihaner, AtillaElemental sulfur was copolymerized with octavinyl polyhedral oligomeric silsesquioxane (OV-POSS) cages in diglyme solution via the inverse vulcanization method and characterized using NMR and FTIR spectroscopic techniques. The polysulfur copolymer called poly(sulfur-random-octavinyl polyhedral oligomeric silsesquioxane) (poly(S-r-OV-POSS)) was cured successfully sequentially at 170, 200 and 230 degrees C without changing the structure of the POSS cages in the polymer backbone. Highly crosslinked poly(S-r-OV-POSS) polymer cured at 200 and 230 degrees C exhibited high thermal stability at high temperatures; the loss of the samples was only 10% weight at 400 degrees C and 27% at 800 degrees C. Finally, the feasibility of poly(S-r-OV-POSS) as an adsorbent for the removal of Hg(ii) ions, as an example of a toxic heavy metal, from an aqueous solution was investigated. Optimization of the pH of the solution and contact time was performed and almost all Hg(ii) ions were collected from the aqueous solution at pH = 7 in 1 h (99% adsorption).Article Citation - WoS: 31Citation - Scopus: 32The Interaction of Halogen Atoms and Molecules With Borophene(Royal Soc Chemistry, 2017) Khanifaev, Jamoliddin; Pekoz, Rengin; Konuk, Mine; Durgun, EnginThe realization of buckled monolayer sheets of boron (i.e., borophene) and its other polymorphs has attracted significant interest in the field of two-dimensional systems. Motivated by borophene's tendency to donate electrons, we analyzed the interaction of single halogen atoms (F, Cl, Br, I) with borophene. The possible adsorption sites are tested and the top of the boron atom is found as the ground state configuration. The nature of bonding and strong chemical interaction is revealed by using projected density of states and charge difference analysis. The migration of single halogen atoms on the surface of borophene is analyzed and high diffusion barriers that decrease with atomic size are obtained. The metallicity of borophene is preserved upon adsorption but anisotropy in electrical conductivity is altered. The variation of adsorption and formation energy, interatomic distance, charge transfer, diffusion barriers, and bonding character with the type of halogen atom are explored and trends are revealed. Lastly, the adsorption of halogen molecules (F-2, Cl-2, Br-2, I-2), including the possibility of dissociation, is studied. The obtained results are not only substantial for fundamental understanding of halogenated derivatives of borophene, but also are useful for near future technological applications.Article Citation - WoS: 8Citation - Scopus: 7Fluorescent and Electrochemical Detection of Nuclease Activity Associated With streptococcus Pneumoniae Using Specific Oligonucleotide Probes(Royal Soc Chemistry, 2024) Goikoetxea, Garazi; Akhtar, Khadija-Tul Kubra; Prysiazhniuk, Alona; Borsa, Baris A.; Aldag, Mehmet Ersoy; Kavruk, Murat; Hernandez, Frank J.Streptococcus pneumoniae (S. pneumoniae) represents a significant pathogenic threat, often responsible for community-acquired pneumonia with potentially life-threatening consequences if left untreated. This underscores the pressing clinical need for rapid and accurate detection of this harmful bacteria. In this study, we report the screening and discovery of a novel biomarker for S. pneumoniae detection. We used S. pneumoniae nucleases as biomarker and we have identified a specific oligonucleotide that works as substrate. This biomarker relies on a specific nuclease activity found on the bacterial membrane, forming the basis for the development of both fluorescence and electrochemical biosensors. We observed an exceptionally high sensitivity in the performance of the electrochemical biosensor, detecting as low as 10(2) CFU mL(-1), whereas the fluorescence sensor demonstrated comparatively lower efficiency, with a detection limit of 10(6) CFU mL(-1). Moreover, the specificity studies have demonstrated the biosensors' remarkable capacity to identify S. pneumoniae from other pathogenic bacteria. Significantly, both biosensors have demonstrated the ability to identify S. pneumoniae cultured from clinical samples, providing compelling evidence of the potential clinical utility of this innovative detection system.Article Citation - WoS: 17Citation - Scopus: 18A Glow in the Dark: Synthesis and Electropolymerization of a Novel Chemiluminescent Terthienyl System(Royal Soc Chemistry, 2009) Asil, Demet; Cihaner, Atilla; Onal, Ahmet M.The synthesis and characterization of a unique (electro)-chemiluminescent monomer based on a terthienyl system, and its corresponding polymer which is the first example of an electro-active chemiluminescent polymer bearing a pyridazine appendage, are described.
