Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Hydrothermal Synthesis and Characterization of Tungsten Oxide Containing Organic-Inorganic Hybrid Material(Izmir Institute of Technology, 2019) Chilufya, Langson; Emirdağ Eanes, Mehtap; Eanes, MehtapImportance and a wide area of applications of solid-state oxides are well known. Metal oxides crystallize in wide variety but simple structures. Lately general opinion is that piezoelectric, ferromagnetic and catalytic properties of simple oxide structures will be improved if the metal oxides could have more complicated and detailed crystal structures. Therefore, research interest increased towards synthesizing complicated crystal structures. One of the methods to increase the complexity of the structure is the modification of inorganic oxides with organic ligands to synthesize complex hybrid materials. There are a great number of organic-inorganic hybrid materials with Keggin or Lindqvist Polyoxometalates structure containing Molybdenum and Tungsten. Usually Obtaining multifunctional hybrid materials, mostly requires grafting an organic functionalized group into the lacunary Keggin structures [XM11O39](n+4)-. Only Tungsten containing polyoxometalates can form a stable lacunary Keggin structures. A Lindqvist structures [M6O19]2- can also self-assemble with organic dyes to form a stable hybrid materials which have important applications. These polyoxotungstates, as an inorganic building blocks, were combined with organic compounds to obtain organic-inorganic hybrid materials. The carboxylic acid functionalized organotin grafted lacunary Keggin structure was coupled with different amines using N, N’-dicyclohexylcarbodiimide (DCC). Another hybrid material was formed by the association of the Lindqvist POM with phosphine based BODIPY derivative dye. The synthesized compounds were all characterized by SEM, FT-IR, TGA and Powder XRD. Since one of the organic moiety use was a BODIPY-type organic dye, the fluorescence properties of these newly synthesized compounds were investigated.Master Thesis Hydrothermal Preparation of Single Crystalline Ceo2 Nanoparticles and the Influence of Alkali Hydroxides on Their Structure and Optical Behavior(Izmir Institute of Technology, 2009) Kepenekci, Özlem; Eanes, Mehtap; Eanes, MehtapSingle crystalline cerium oxide nanoparticles were synthesized via hydrothermal method by mixing aqueous solution of cerium nitrate [Ce(NO3)3.6H2O] with an alkali base. Several characterization methods were used to identify morphology and crystalline nature such as X-ray Diffraction, Scanning and Transmission Electron Microscopes. This study is divided into three parts. In the first part, some controlling parameters like, that were affecting size and shape of CeO2 nanoparticles, were studied. It was found that size of CeO2 nanoparticles increased when increasing both reaction time and temperature. Alkali base concentration promoted the particle growth. Also, particle morphology was more uniform rather than aggregated in presence of higher concentrated alkali base. When the alkali base type was changed, the use of NaOH produced larger cubic nanocrystals of CeO2 than KOH and LiOH.Second part is related to determine the optical properties of CeO2 nanoparticles. Based on the UV-Vis and Fluorescence Spectroscopy results, size, bandgap and defect level of CeO2 nanoparticles can be easily determined. Nanoparticles in presence of NaOH alkali base were found to produce less defective CeO2 nanoparticles as compared to KOH and LiOH. The last part of this work is to evaluate the shape effect on morphology, size and optical properties of CeO2 nanoparticles. Rod crystals of CeO2 were produced when the hydrothermal synthesis temperature was low (120°C) or when the reaction time was short (1 hour). When the synthesis temperature was higher than 160°C well defined cubic crystals of CeO2 started to form.Master Thesis Hydrothermal Synthasis and Investigation of Catalytic Activities of Cerium Oxide Nanoparticles(Izmir Institute of Technology, 2013) Boz, Mithat; Eanes, Mehtap; Çağır, AliSingle crystalline cerium oxide nanoparticles were synthesized with hydrothermal method by mixing cerium nitrate [Ce(NO3)3.6H2O] aqueous solution with NaOH and urea. SEM, TEM and XRD characterization methods were used in order to identify morphology. First part of the study includes the work on effect of hydrothermal parameters, such as base type and concentration, surfactant, reaction temperature, and time on particle size and morphology. The reaction time, temperature and concentration trials were carried out for urea only. When base types were compared, smaller particles were synthesized in the presence of NaOH yet smaller crystalline sized particles were obtained in the presence of urea. Effect of surfactant was investigated however there was no significant effect on size or morphology. Effect of concentration was clear, cubic and triangular prism shaped particles obtained for concentrations lower than 1M, and for concentration higher than 1M, agglomerated spherical particles were obtained. Reaction time and temperature were also investigated and all the reactions resulted in agglomerated non-uniform spherical particles. There was no considerable difference in particle and crystalline size for these samples. Due to the sub-micron size of CeO2 synthesized using urea, CeO2 nanoparticles synthesized using NaOH for catalysis. Second part includes the investigation of catalytic property of CeO2 nanoparticles. CeO2 nanoparticles were used as catalyst in the synthesis of flavone from 2‟-hydroxychalcone. Total flavone yield was approximately 42.5 %. Several reaction parameters were studied in order to achieve the flavone synthesis. TLC, GC-MS and NMR were used in order to monitor the results of the reactions.Master Thesis Hydrothermal Synthesis and Characterization of Single Crystalline Ceo2 Nanoparticles for Catalytic Applications(Izmir Institute of Technology, 2012) Meşin, Taylan; Eanes, MehtapSingle crystalline cerium oxide nanoparticles were synthesized with hydrothermal method by mixing cerium nitrate[Ce(NO3)3.6H2O] aqueous solution with alkali bases CsOH and RbOH. SEM, TEM and XRD characterization methods were used in order to identify morphology. First part of the study includes the work on effect of hydrothermal parameters, such as reaction temperature, reaction time, alkali base type and concentration on particle size and morphology. It was prooved that the size of ceria nanoparticles is directly proportional with the reaction time. The reaction temperature is also an important parameter that effect the morphology of nanoparticles. At 120 oC nanoparticles form rod like structure and as time goes they start to form cubic crystals. When the alkali base and concentration was changed the results showed that higher base concentration favors the particles to form bigger structures than that of lower concentrations. In addition, optical properties of CeO2 nanoparticles were studied by using the UV-Vis and Fluorescence Spectrometry. UV-Vis Spectroscopy results show that particle size of CeO2 nanoparticles synthesized in the presence of 8M RbOH are larger than that of synthesized in presence of 8M CsOH. When the reaction time decreases the Ce3+ defect increases based on the results of Fluorescence Spectrometry results. Second part of the study includes catalytic property of CeO2 nanoparticles. Ceria nanoparticles were used as catalyst in the synthesis of flavone from 2’-hydroxychalcone. Several reaction parameters were studied in order to achieve the flavone synthesis. TLC, GC, GC-MS and NMR were used in order to monitor the results of the reactios.Master Thesis Hydrothermal Synthesis and Structural Characterization of Open-Framework Metal Phosphates Templated With Organic Diamines(Izmir Institute of Technology, 2012) Ece, Özlem; Eanes, MehtapIn recent years, hydrothermal synthesis and structural characterization of open-framework metal phosphates templated with organic diamines have attracted the attention of scientists because they represent the interaction between organic and inorganic chemistry and can be applied in lots of branches of chemistry with their different characteristic properties. In this study, a novel open-framework polyoxometal phosphate compound (4,4’-bpyH2)2(4,4’-bpyH)[PCoW11O39].H2O was synthesized with hydrothermal method as red crystals. The compound crystallizes in the space group P2(1)/n of the monoclinic system with four formula units in a cell. The crystal is a Keggin polyoxometalate structure and contains free 4,4’-bipyridine groups and water molecule between the clusters. In addition to this novel compound, three known compounds were synthesized. Co(4,4’-bpy)2(VO2)2(HPO4)2 red crystals were synthesized hydrothermally and the compound crystallizes in the space group C2/c of the monoclinic system with four formula units in a cell. The crystal consists of [(VO2)(HPO4)]∠helical chains and [Co(4,4’-bpy)2]2+ frameworks. Also, NaCo3(PO4)(HPO4)2 pink crystals were obtained with using hydrothermal synthesis. The compound crystallizes in the space group C2/c of the monoclinic system with four formula units in a cell. In the structure, CoO6 chains connect to the PO4 and HPO4 groups. Lastly, (enH2)3[CoW4P4O28] blue crystals were synthesized with hydrothermal method and crystallizes in the space group I4(1)/a of the tetragonal system with four formula units in a cell. The crystal consists of a [Co3W4P4O28]6- anion and three free ethylenediaminium (N2H10C2)2+ cations.Master Thesis Hydrothermal Synthesis and Characterization of Ethylenediamine-Containing Molybdenum Oxides(Izmir Institute of Technology, 2006) Gün, Özgül; Eanes, MehtapRecently, hydrothermal synthesis and characterization of organic-inorganic hybrid materials has attracted great attention.A novel organic-inorganic hybrid material, [Cu(en)MoO4], was hydrothermally synthesized as blue crystals. A mixture of Na2MoO4 CuCl2 NaCl, ethylenediamine and water was loaded into a 23 mL autoclave and heated at 170°C for 72 h. The compound crystallizes in the space group P2(1)/c of the monoclinic system with four formula units in a cell of dimensions a . 7.6743(15) b . 9.4364(19)c . 9.9538(2) . 72.266(3) V . 686.6(2) The structure is composed of {MoO4}tetrahedra and {CuN2O4} octahedra. Each pair of copper octahedra forms a binuclear edge-sharing unit through a {Cu2O2} interaction. The binuclear octahedral units are interconnected through the bridging {MoO4} yielding a layer structure.Purple crystals of a known hybrid material, [Cu(en)2]2[Mo8O26], was hydrothermally obtained under different reaction conditions. A mixture of Na2MoO4 ethylenediamine and water was loaded into the autoclave and heated at 170°C for 72 crystallizes in the space group Pbca of the orthorhombic system with eight formula units in a cell of dimensions a . 13.516 b . 15.548(3) c . 16.725(3) V . 3514.7(12) The structure consists of linked through groups. Each unit forms covalent interactions with two units.Green and black crystals were obtained from the reaction of with different ratios. Via the reaction of NaCl, ethylenediamine and yellow crystals were obtained.Master Thesis Hydrothermal Synthesis and Characterization of Transition Metal (mn and V) Oxides Containing Phosphates(Izmir Institute of Technology, 2006) Eral, Leyla; Eanes, MehtapThe synthesis of new manganese phosphate compound, Sr2MnP3O11, by hydrothermal reaction of Mn2O3, SrCO3 and H3PO4 in presence of water at 230 for 5 days is reported. The compound crystallizes in the space group P 21/c of the monoclinic system with three formula units in a cell of dimensions a.6.6410(13) b.6.8341(14) c.19.055(14) .99.22(3) V.853.6(3) The structure is composed of MnO6, PO4 and P2O7 groups and Sr cations. It has three dimensional structure including channels n which the Sr cations are placed.The pale pink single crystals of the Hureaulite mineral, Mn5(H2O)4[PO3(OH)]2[PO4]2, were synthesized hydrothermally via the reaction of SrCO3, MnCl2, H3PO4 and H2O at 180C for 3 days. The compound is in the crystal system of monoclinic with unitcell parameters a.17.600(4), b.9.1214(18), c.9.4786(19) and .96.52(3)and in the space group C2/c. The structure possesses a three-dimensional architecture containing channels and is made up of MnO6 and PO4, which are joined with others by sharing corners.All detailed structural information of the synthesized materials was done via commercial software programs SHELX and Crystal Structure.Master Thesis Hydrothermal Synthesis and Characterization of Transition Metal Oxides(Izmir Institute of Technology, 2004) Şahin, Aytaç; Eanes, MehtapHydrothermal method has proven to be an excellent method for the synthesis of novel metal oxides and vanadates. This research pertains to the synthesis of novel lead chlorovanadate compound and of a known alkali metal trivanadate compound, KV3O8 by hydrothermal method This method has been used to synthesize many inorganic oxide compounds Hydrothermal synthesis is the use of aqueous solvents under high temperature and high pressure to dissolve and recrystallize materials. Compounds with interesting structure and physical properties are often obtained from this technique that is known as one of the low-temperature synthesis techniques for solid state compounds. There are many studies that have been done on oxides in the Pb-V-O systems There are also many vanadium oxides containing Pb, V, O elements in Pb-V-O system such as Pb1.32V8.35O16.7, PbV6O11, PbV2O6, Pb2V3O8.5, and .-PbxV2O5 bronzes (x . 0.3). In an attempt to synthesize vanadium oxides at low temperature, we were able to obtain needle shaped yellow crystals of PbVO3Cl. In the nature, there is a kombatite mineral, Pb14(VO4)2O9Cl4, with the same composition of elements. A new lead chlorovanadate, PbVO3Cl, was obtained from the reaction of NaVO3 and PbCl2 in aqueous solution of B(OH)3. The compound was prepared in an autoclave that was filled with aqueous solution of B(OH)3 and heated at 170oC for 3 days. The compound crystallizes in the space group Pnma of the orthorhombic system with formula units in a cell of dimensions a . 10.022(2)Master Thesis Hydrothermal Synthesis of Solid State Materials and Crystallography(İzmir Institute of Technology, 2004) Özmen, Bahar; Eanes, MehtapThe structure solution of the new polyoxovanadate compound([V16O31(OH)7]Cl· 15H2O), has been done by the SHELX crystal solution software. The compound was synthesized solvothermally at 170 0C in the Northwestern University. The compound crystallizes in the space group C2/c of the monoclinic system with eight formula units in a cell of dimensions a = 18.070 (2) Å, b = 17.414 (2) Å, c = 15.1154 (18) Å, â= 97.696 (2)°, V= 4713.8 (10) Å3 (T = 153 K). The structure is composed of vanadium-oxygen clusters encapsulating Cl¯ anion. Each of the V centers has square pyramidal geometry coordinated by five O atoms. The 16 (VO5) units are fused together through common edges to form (V16O38) cage with Cl¯ anion in the middle. The single crystals of the [Ni(en)3(VO3)2] compound was synthesized by hydrothermal method. [Ni(en)3(VO3)2] compound is in the crystal system of hexagonal and in the space group P61. The unit cell parameters are a = 8.9940 (13) Å, b = 8.9940 (13) Å, c = 34.001 (7) Å and á = 90 0, â = 90 0, ã = 120 0. The structure is composed of VO4 tetrahedras which are joined with others by sharing corners into infinite chains running along the c axis. The complex cation [Ni(en)3]2+ are located between the chains The chain in the compound has a repetitive sequence of 12-nuclear corner-sharing tetrahedras. The compound was synthesized at 160 0C for 3 days in the steel reaction autoclaves which have PTFE (Polytetrafluoroethylene) cups in them.Master Thesis Hydrothermal Synthesis and Characterization of Vanadium and Tungsten Oxide Containing Organic-Inoganic Hynrid Material(Izmir Institute of Technology, 2011) Önen, Banu; Eanes, MehtapHydrothermal synthesis of transition metal oxide containing organic-inorganic hybrid materials has attracted great attention recently. Two novel organic-inorganic hybrid materials (4,4’-bipy)3[HPW12O39] and [Cu(4,4’-bipy)4][HPW12O40] were hydrothermally synthesized as green and purple crystals respectively, from the reaction of Na6[H2W12O40], CuCl2.2H2O, 4,4’- bipyridine and H3PO4 in a 23 ml autoclave at 170°C for 72 hours. The compound (4,4’- bipy)3[HPW12O39] crystallizes in the space group P21/n of the monoclinic system with four formula units in a cell with dimensions a = 13.503(3) Å, b = 26.726(5) Å, c = 15.169(3) Å and V = 5397.3(19) Å 3 . [Cu(4,4’-bipy)4][HPW12O40] crystallizes in the space group Pbcn of the tetragonal system with eight formula units in a cell of dimensions a = 20.236(4) Å, b = 25.635(5) Å, c = 20.236(4) Å; V = 10497(4) Å 3 . Both of the compounds are Keggin polyoxometalate structures. (4,4’-bipy)3[HPW12O39] contains free 4,4’-bipy groups among the clusters while in [Cu(4,4’-bipy)4][HPW12O40] 4,4’-bipy ligands are coordinated to Cu 2+ ions. A novel compound (H2NC4H8NH2)[(VO)2(PO4)2] was synthesized hydrothermally from the reaction of NaVO3, V2O5, ethylenediamine and H3PO4 at 170°C for 72 hours. The compound crystallizes in the space group P-1 of the trigonal system with five formula units in a cell of dimensions a= 6.3345(13) Å, b= 6.3353(13) Å, c= 15.940(3) Å, V=639.6(2) Å 3 . (H2NC4H8NH2)[(VO)2(PO4)2] displays a layered structure with protonated piperazine groups between layers. In addition to the novel compounds, several known compounds were synthesized as well. Blue crystals of (VO)(H2PO4)2 were obtained hydrothermally from the reaction of NaVO3, ethylenediamine and H3PO4 at 170°C for 72 hours. (C5NH6)4.5(H3O)1.5[P2W18O62] , a known compound also, was synthesized from the reaction of Na2WO4 .2H2O, CuCl2.2H2O, pyridine and H3PO4 at 170°C for 72 hours