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    Novel coordination compounds of alkaline earth metals with coumarilic acid. Synthesis and characterization
    (Elsevier B.V., 2021) Karaer, Emrah; Köse, Dursun Ali; Şahin, Zarife Sibel; Şahin, Onur
    In this study, novel coordination compounds of coumarilic acid with 2A group alkaline earth metal cations [Mg2+ (1), Ca2+ (2), Sr2+ (3) and Ba2+(4)] were synthesized and structural characterized. The structural properties of the new molecules obtained were studied by melting point, elemental analysis, infrared spectroscopy, single crystal x-ray diffraction (SC-XRD), powder x-ray diffraction (P-XRD) spectroscopy. In addition, the thermal stability of the compounds were examined by thermal analysis (TGA/DTA) curves in an inert nitrogen atmosphere. When the structural properties of the molecules were examined, it was seen that the structure numbered 1 {[Mg(H2O)6].2(C9H5O3)} differed from the others and it was a kind of aqua complex. The coumarilate anions anionically located outside the coordination sphere serve as the counter-ion of the molecule. It has been determined that the other structures 2 {?-(H2O)2[Ca(C9H5O3)(H2O)3]2.2(C9H5O3)}, 3 {?-(H2O)3[Sr(C9H5O3)(H2O)2]2.2(C9H5O3)} and 4 {?-(H2O)3[Ba(C9H5O3)(H2O)2]2.2(C9H5O3)} are in polymeric form and the coordination number of metals are eight. According to the spectroscopic analysis, these three structures are thought to be in isostructure form. It has been determined that in the unit cell in the structure 3 whose single crystal structure has been resolved, aqua and coumarilate ligands of two metal cations are connected to each other in the bridge position and coordination is ensured with aqua and bidentate anionic coumarilate ligands located in the terminal position. At the end of thermal decomposition, it was determined that relevant metal oxide residues remained in all structures and this situation was defined by powder XRD. © 2021
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    Novel mixed ligand complexes of alkaline earth metals with coumarilic acid and nicotinamide
    (Turkish Chemical Society, 2021) Karaer, Emrah; Köse, Dursun Ali
    Coordination compounds with mixed ligands were synthesized with 2A group (Mg2+, Ca2+, Ba2+, Sr2+) alkaline earth metal cations of coumarilic acid and nicotinamide ligands. Afterward, the structural properties of these new molecules were investigated by melting point, elemental analysis, infrared spectroscopy, thermal analysis (TGA / DTA) curves, powder X-ray diffraction (P-XRD) spectroscopy. It has been suggested that the complex structure with the Mg2+ metal center is different from the other three structures. In this structure, it was determined that four aqua and two nicotinamide ligands were located in the coordination sphere, and the coordination number was six, as expected. With two monoanionic coumarilic acids located outside the coordination sphere, complex charge equivalence was achieved. The other three molecules, Sr2+ and Ba2+, have iso-structural properties, and it is suggested that both structures contain a dinuclear metal center, and two aqua ligands are located in the bridging position between metal centers. Besides, the two coumarilate ligands involved in coordination are thought to coordinate with the primary metal cation through carbonyl and acidic oxygens while coordinating with the secondary metal cation through furan oxygen, providing the third bridge connection between metal centers. Metal cations with nine coordination numbers complete the coordination sphere with two terminal aqua and one nicotinamide ligands, each included in the structure. In the molecule with Ca2+ cation, which differs little from these metal cation structures, the difference according to these structures can be interpreted as the coordination of furan oxygen with the secondary metal center due to the octet coordination of the Ca2+ cation. From the thermal analysis curves, it was determined that only the Mg2+ cation complex contained hydrate. As a result of thermal decomposition, it was determined that relevant metal oxide residues remained in all structures, and this situation was defined by powder XRD. © 2021, Turkish Chemical Society. All rights reserved.
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    Toprak alkali metal katyonlarının kumarilik asit ve kumarilik asit/nikotinamid komplekslerinin sentezi ve yapısal özellikleri
    (Hitit Üniversitesi, 2019) Karaer, Emrah; Köse, Dursun Ali
    Günümüzde, yapılarında heteroatom ihtiva eden halkalı bileşikler ile bunların türevleri, tıp ve tarım gibi çeşitli alanlarda kullanılmaktadır. Bu halkalı bileşiklerden birisi de kumarilik asittir. Kumarilik asit bir benzen halkası ve bu halkaya birleşmiş 2-furan karboksilik asit halkasından oluşan çift halkalı bir yapıya sahiptir. Halen, doğal veya sentetik türevlerinin kullanımı ile ilgili birçok farmasötik uygulama çalışması vardır. Kumarilik asit türevleri hakkında çok sayıda çalışma yapılmış olmasına rağmen (Masche ve ark., 1999; Karaliota ve ark., 2001), metal kompleksleri üzerindeki çalışmaların sayısı sınırlıdır. Bu çalışmalar da daha çok geçiş metal kompleksleri ağırlıklı olup yapısal karakterizasyonları tamamlanmış moleküllerdir (Köse, 2014). Bu çalışmada, 2+ yükseltgenme basamağına sahip 2A grubu toprak alkali metal katyonlarının (Mg2+, Ca2+, Ba2+, Sr2+) kumarilik asit ve kumarilik asit/nikotinamid koordinasyon bileşikleri sentezlendi. Elde edilen yeni moleküllerin yapısal özellikleri erime noktası, elemental analiz, infrared spektroskopi, tek kristal X-ışını difraktometresi (SC-XRD) ve toz X-ışını difraktometrsi ile çalışıldı. Ayrıca bileşiklerin termal kararlılıkları inert azot atmosferinde termal analiz (TGA/DTA) eğrileri ile incelendi.