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    A new derivative of 1-allyl-3-methylimidazolium chloride as ionic liquid compound: Synthesis, physical properties and DFT studies
    (Elsevier, 2024) Yildiz, Murat; Gumustas, Sila; Kinal, Armagan; Alp, Serap
    This study aimed to improve the physical properties of 1-allyl-3-methylimidazolium chloride (AMIMCl) by synthesizing a new derivative, 1-allyl-2-hydroxymethyl-3-methylimidazolium chloride (AHMMIMCl). The synthesized AHMMIMCl was characterized using FT-IR, (HNMR)-H-1, (CNMR)-C-13, TGA, and DSC techniques, and its physical and computational properties were compared with those of AMIMCl. Experimentally, AHMMIMCl exhibited a lower viscosity (Delta eta =267.57 cP), a significantly reduced melting point (Delta T =similar to 100 degrees C), and lower conductivity (Delta(sigma max)=30.72 mS.cm(-1) at 25 degrees C). The stable geometries of the cations, ion-pairs, and dimer structures were estimated employing DFT methods. The nature of the cation-anion interaction was analyzed by the natural bond orbital (NBO) and electrostatic potential (ESP) analyses. The physical properties of the newly synthesized compound are found to be in agreement with DFT calculations. Additionally, the new derivative demonstrated enhanced viscosity and melting point compared to the parent compound (AMIMCl), with no significant alteration observed in the hydrogen bond length within the anion-cation interaction. These results indicate the potential applicability of the new product as a substitute for AMIMCl.
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    Computational determination of ring opening polymerization reaction mechanism of alpha-angelica lactone
    (Elsevier Science Bv, 2018) Gumustas, Sila; Balcan, Mehmet; Kinal, Armagan
    In the present study, we investigated the ring opening polymerization of alpha-angelica lactone (AL) catalyzed by the tin (II) 2-ethylhexanoate, Sn(Oct)(2) through the coordination insertion mechanism by employing the semi empirical PM6, PM6-D3H4, PM7, and the DFT-B3LYP, B3LYP-D2 and omega B97X-D methods in both gas and solvent (toluene, THE, DMF and DMSO) media. The DFT calculations revealed that the initiation stage consists of three steps; a stable complex formation, a low energy conformational transformation and the ring opening. NBO analysis was conducted to explain the interactions between the electrophilic and nucleophilic centers. The omega B97X-D method gives the closest result (30.2 kcal/mol) to the experimentally found activation barrier (26.3 kcal/mol) for this system. Therefore, omega B97X-D has the best performance among all the methods studied here. The mechanism of the addition of a new monomer to the active chain, which constitutes the propagation stage of the polymerization, was further investigated and, as expected, a lower barrier compared to that of the initiation stage was obtained (14.5 kcal/mol). The PCM calculations revealed that the solvent did not affect the activation barrier. In addition, the enthalpy of ring opening polymerization of alpha-angelica lactone was calculated based on the initiation and propagation stages and the thermodynamics of the system was discussed.
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    Investigation of initiator metal efficiency in the ring-opening polymerization of lactones: an experimental and computational study
    (Wiley, 2022) Gumustas, Sila; Balcan, Mehmet; Kinal, Armagan
    Poly(delta-valerolactone) (PVL) was synthesized by ring-opening polymerization (ROP), employing tin(II) acetate (SnAcet(2)), lead(II) acetate trihydrate (PbAcet(2)center dot 3H(2)O) and cadmium(II) acetate dihydrate (CdAcet(2)center dot 2H(2)O) complexes as initiators without any co-initiator. The highest molecular weight PVL (45 438 g mol(-1), 91% yield) was obtained with CdAcet(2)center dot 2H(2)O. Characterization of the synthesized products was performed by FTIR, H-1 NMR, C-13 NMR, gel permeation chromatography (GPC), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS), TGA and DSC. Electrostatic data (natural bond orbital and Hirshfeld) and lowest unoccupied molecular orbital (LUMO) of the initiators were obtained by using several density functional theory methods (B3LYP, omega B97X-D, PBEPBE, BPV86, HSEH1PBE, MPW1PW91, M06 and M062X). In addition, the initiation stage of the ROP mechanism of delta-valerolactone with these metal acetate complexes was investigated at the omega B97X-D level with a mixed basis set. It was computationally determined that the most effective initiator was also CdAcet(2). The molecular weight variation of PVLs synthesized with these initiators can be associated with the combined evaluation of atomic charge, LUMO and orbital overlap analyses. The computationally obtained reaction barriers for the initiators support this idea, also. In addition, toxicity tests carried out for PVLs synthesized with acetate complexes containing Sn, Cd and Pb revealed that the Sn and Cd complexes do not have a toxic effect on cell viability at some dilution rates. (C) 2021 Society of Industrial Chemistry.
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    Polyglycolide-montmorillonite as a novel nanocomposite platform for biosensing applications
    (Royal Soc Chemistry, 2017) Unal, Betul; Yalcinkaya, Esra Evrim; Gumustas, Sila; Sonmez, Burak; Ozkan, Melek; Balcan, Mehmet; Demirkol, Dilek Odaci; Timur, Suna
    In catalytic biosensors, the immobilization of biomolecules in a suitable matrix is one of the vital parameters for obtaining improved systems. Clays, which are intercalated with various organic compounds, have a great tendency to develop biosensors with high stability, sensitivity and reproducibility. Herein, a polymer/clay nanocomposite based on natural silicate montmorilonite (Mt) and a biodegradable polymer polyglycolide (PGA) was prepared and characterized by FT-IR, thermogravimetric analysis, differential thermogravimetric analysis and X-ray diffraction. Then, the resulting matrix was used as a fixation matrix for pyranose oxidase (POx), which was selected as a model enzyme. The bioactive layer was fabricated by immobilization of POx on glassy carbon electrodes by means of PGA-Mt and bovine serum albumin. The POx biosensor revealed a good linear range from 0.01 to 0.5 mM glucose with a LOD of 1.2 mM. After the optimization of the working and preparation conditions, characterization studies were performed for glucose detection. Finally, the PGA-Mt/POx biosensor was confirmed to have detected glucose in beverages without needing any sample pre-treatment.