000107707 001__ 107707
000107707 005__ 20211025114925.0
000107707 037__ $$aTESIS-2021-285
000107707 041__ $$afra
000107707 080__ $$a546
000107707 1001_ $$aBasdouri, Zeineb
000107707 24500 $$aPréparation, caractérisation structurale et physico-chimique de nouveaux composés de coordination des métaux zinc et cuivre
000107707 260__ $$aZaragoza$$bUniversidad de Zaragoza, Prensas de la Universidad$$c2020
000107707 300__ $$a173
000107707 4900_ $$aTesis de la Universidad de Zaragoza$$v2021-281$$x2254-7606
000107707 500__ $$aPresentado: 25 09 2020
000107707 502__ $$aTesis-Univ. Zaragoza, , 2020$$bZaragoza, Universidad de Zaragoza$$c2020
000107707 506__ $$aall-rights-reserved
000107707 520__ $$aWe summarize here the most important aspects of the work carried out in this Thesis and<br />described in the previous chapters, together with its conclusions. The thesis, entitled<br />"Preparation, structural and physicochemical characterization of novel coordination<br />compounds of zinc and copper" is based on the study of coordination compounds, formed on<br />the one hand by zinc with the hexamethylenetetramine ligand and on the other hand by copper<br />with the orotate ligand. This work has been divided into six chapters for a clearer exposition of<br />the results obtained.<br />In the first chapter, we present general information on coordination chemistry in order to reprise<br />some basic concepts, followed by a brief review of the intermolecular interactions that provide<br />the stability and cohesion among the entities in the solids reported in this thesis. A bibliographic<br />study is also presented, based on the complexes formed by the metals and ligands used in this<br />work for the development of new coordination compounds. This begins with a brief<br />introduction to coordination chemistry followed by a definition of a coordination complex and<br />the entities that form it. We also focus on the geometries that can be found in coordination<br />complexes as well as the steps to follow in order to name such a complex. The text continues<br />with an overview of the phenomena of crystallization and polymorphism followed by a<br />description of Ostwald’s rule of stages. In the remainder of this chapter, intermolecular<br />interactions such as hydrogen bonds, Van der Waals forces and - interactions, which are<br />responsible for the cohesion and stability of our synthesized materials, are discussed. Regarding<br />the bibliographic study, we present in the rest of this chapter the principal characteristics of zinc<br />and copper as well as the ligands hexamethylenetetramine and orotic acid, accompanied by<br />some examples of the complexes synthesized previously, as drawn from the literature with their<br />crystallographic characteristics.<br />In the second chapter, the different characterization techniques used in this work as well as the<br />associated experimental devices are described. After a brief introduction, the principles and<br />practical implementation of X-ray structure analysis are presented. This technique is the<br />mainstay of our work. After a suitable crystal has been chosen and mounted for single crystal<br />X-ray diffraction, the analysis is carried out in three steps. The first step is to determine the<br />crystal lattice, then perform the data collection and finally solve the structure. For our<br />compounds, we have used two types of diffractometers; one is an Enraf-Nonius CAD-4 with<br />FR590 X-ray generator, and the other is a Rigaku/Oxford Diffraction Xcalibur/Sapphire 3. The<br />thesis describes in detail the different steps for the two diffractometers. Subsequently, the text<br />describes the principle of Hirshfeld surface analysis, which allowed us to study the<br />intermolecular interactions in our synthesized compounds. The principle of X-ray powder<br />diffraction is described; this analysis allowed us to ensure the purity of our compounds using<br />the Rietveld method, which is described later. In the rest of this chapter, we also describe the<br />principle and the equipment of infrared absorption spectroscopy, used to study the vibrations<br />of the different functional groups in our synthesized materials. This chapter ends with<br />background on thermal analysis and especially thermogravimetric analysis (TGA) to study the<br />stability and thermal behavior of our materials.<br />The third chapter is focused on the study of organic-inorganic hybrid compounds based on zinc<br />and hexamethylenetetramine. A brief introduction is followed by a description of the synthetic<br />procedure and the strategy for preparing crystals. This chapter presents a study of three hybrid<br />zinc compounds. These are prepared by slow evaporation of solvent at room temperature; two<br />of the new products emerge from the same preparation. The detailed structural study as well as<br />the Hirshfeld surface analysis of two anhydrous complexes, [hmtaH]ZnCl3 and<br />(hmtaCH2OH)ZnCl3, are presented. The first compound, of formula (C6H13N4)ZnCl3,<br />crystallizes in the orthorhombic system, space group Pnma. Its structure is formed by<br />[hmtaH]ZnCl3 molecules. These entities arrange in layers parallel to the (101) plane. The<br />cohesion between the molecules is ensured by N-H...Cl and C-H...Cl hydrogen bonds within<br />layers and by van der Waals interactions between layers. The second compound, of formula<br />(C7H15N4O)ZnCl3, crystallizes in the triclinic system, space group P-1. Its structure is formed<br />of discrete [(C7H15N4O)ZnCl3] molecules, which in the crystal form a compact bimolecular<br />aggregate. O-H...Cl hydrogen bonds connect neighbouring molecules, forming an unbounded<br />chain of dimers. The cohesion of the structure is maintained by Van der Waals interactions<br />between neighbouring chains of dimers. The Hirshfeld surface analysis confirms the type of<br />intermolecular interactions responsible for the structural stability of these compounds. The<br />remainder of this chapter deals with the structural, comparative and physicochemical study of<br />the hemihydrate compound [Zn(H2O)6][{(CH2)6N4}ZnCl3]2·0.5H2O. The structural study<br />establishes that it crystallizes in the trigonal system, space group P-3c1. Its structure can be<br />described as consisting of stacks parallel to the crystallographic c axis: Firstly, cationic<br />Zn1(O1WH2)6 octahedra and disordered unligated water molecules line up along the three-fold<br />symmetry axis at x = 0, y = 0; secondly, the anionic complexes are arranged along the threefold<br />axes at (1/3, 2/3, z) and (2/3, 1/3, z). The stability of this arrangement is governed by O-H…N and O-H…Cl hydrogen bonding interactions between cation and anion chains, with a lesser contribution within the cation/water chains from O-H…O H-bonds with the partially<br />occupied free water as receptor. It is noted that this material is the second hydrate synthesized<br />in this system. The relationship between the packing in the new structure and that of the<br />previous hexahydrate [Zn(H2O)6][{(CH2)6N4}ZnCl3]2·6H2O, which was reported by Thomas<br />C. W. Mak in 1986, is described. The comparative study showed that the two structures differ<br />essentially in the proportion and arrangement of the water of hydration. The purity of this<br />compound was checked by X-ray powder diffraction analysis using the Rietveld method. Then,<br />for the vibrational study of our material, a theoretical semi-empirical calculation of the infrared<br />spectrum using the Cache program was carried out in order to compare the different bands in<br />the theoretical spectrum with those in the experimental spectrum. The thermal stability of this<br />hemihydrate compound was subsequently studied by TGA-DTG. Finally, Hirshfeld surface<br />analysis and fingerprint plots were applied to confirm the existence of weaker intermolecular<br />interactions in the crystal.<br />In the fourth chapter, we present the study of two copper orotates of formulas<br />(Cs)2[Cu(orotate)2(H2O)2]·4H2O and (Cs)2[Cu(orotate)2]·2H2O, which were synthesized from<br />the same starting solution. The first compound is not stable and it changes over time to give rise<br />to crystals of the second phase. These two compounds crystallize in the triclinic system, space<br />group P-1. The structure of the (Cs)2[Cu(orotate)2(H2O)2]·4H2O compound is formed by layers<br />of [Cu(HOr)2(H2O)2]2- anions parallel to the (001) plane. The layers are linked to each other by<br />hydrogen bonds involving the H2O2W and H2O3W water molecules. The cesium cations are<br />located in the inter-layer space and also contribute to the cohesion between layers. As for the<br />structure of (Cs)2[Cu(orotate)2]·2H2O, it presents a layer of double chains of bimolecular<br />complex aggregates parallel to (010). N3-H3 ... O14 and N13-H13 ... O4 hydrogen bonds ensure<br />cohesion and progression in a chain. The hydration water molecules as well as the Cs+ cations<br />are located in the inter-layer space and ensure cohesion between layers. Subsequently, the<br />comparative study of Cs2[Cu(orotate)2(H2O)2]·4H2O with its isomorph of the previously<br />studied analogous nickel compound, namely Cs2[Ni(HOr)2(H2O)2]·4H2O, has been conducted.<br />In fact, the two structures have a clear resemblance and some points of difference. However,<br />this is due to the Jahn-Teller effect, which is present only in the copper compound. The<br />transformation of crystals of the first compound into crystals of the second compound involves<br />the egress of four water molecules per formula unit accompanied by the modification of the<br />coordination about the copper center from octahedral six-coordinate to distorted square<br />pyramidal [4+1]. Both compounds have also been characterized by infrared absorption<br />spectroscopy followed by thermal analysis, TGA-DTG, for the (Cs)2[Cu(orotate)2]·2H2O<br />compound.<br />In the fifth chapter, we describe the study of a new copper orotate with the organic cation<br />guanidinium, of formula, (CH6N3)2[Cu (orotate)2]·2H2O. This complex has been synthesized<br />by slow evaporation of solvent at room temperature. Its structure is formed by layers of the<br />[Cu(HOr)2]2- anion and hydration water molecules parallel to the (001) plane. Between these<br />layers, the guanidinium cations (CH6N3)+ are located; they are all linked together via hydrogen<br />bonding interactions. Analysis of the Hirshfeld surfaces aids in the interpretation of the<br />intermolecular interactions. Thermal analysis has shown that this compound is stable at<br />temperatures ≤ 100°C. The comparative study with Cs2[Cu(HOr)2]·2H2O shows the effect of<br />the change of counterion on the structure and non-covalent interactions. It is noted that the<br />compound (CH6N3)2[Cu(HOr)2]·2H2O is more stable than the analogue with the Cs+ cation;<br />this can be explained by the capacity of the guanidinium cation (CH6N3)+ to form hydrogen<br />bonds, which enhances its contribution to maintaining the stability of the compound.<br />In the sixth and last chapter, we have identified a crystallization process showing a neat<br />solution-mediated single crystal to single crystal transformation between two conformational<br />polymorphs of (nBu4N)2[Cu(orotate)2]·2H2O, with the co-existence of both forms in the same<br />experimental conditions for an extended period of time; on this basis they might be considered<br />concomitant polymorphs. However, the crystal transformation process obeys Ostwald’s rules<br />of stages with superposition of the corresponding domains. The two polymorphs can be<br />distinguished by their difference in colour and their morphologies. The crystals of form I<br />develop as blue green needles while those of form II are blue-purple blocks. The square planar<br />geometry around the Cu2+ ion for polymorph I is distorted while in polymorph II it is flat. The<br />geometry calculated by the program SHAPE has a deviation of 5.08% compared to an ideal<br />square-planar coordination and 16.01% compared to an ideal tetrahedral coordination for form<br />I and a 0.41% deviation from an ideal square-planar coordination and 33.61% compared to an<br />ideal tetrahedral coordination for form II. Polymorph I of (nBu4N)2[Cu(orotate)2]·2H2O<br />crystallizes in the monoclinic system, space group P21/n; as for polymorph II, it crystallizes in<br />the same crystal system, with space group P21/c. The structures of these two polymorphs are<br />constituted by anionic ribbons formed by [Cu(HOr)2]2- anions and uncoordinated water<br />molecules extending along the a axis. The cohesion within a ribbon is ensured by hydrogen<br />bonds. The inter-ribbon space is filled by nBu4N+ cations. The cohesion between the anionic<br />ribbons and the organic cations is maintained by van der Waals interactions. The contributions<br />of the interactions observed on the Hirshfeld surface (dnorm) and the corresponding 2D<br />fingerprints plots for the two polymorphs are very similar. X-ray powder diffraction analysis<br />allowed us to confirm the purity of the two compounds using the le Bail method. Detailed<br />vibrational study by infrared absorption spectroscopy and thermal analysis by TGA-DTG were<br />conducted. IR spectroscopy analysis showed the decrease of symmetry in form I compared to<br />form II. This results in a splitting of the vibration bands. According with the TGA data, both<br />crystals lose their water molecules below 90°C with the water molecules of form I being lost at<br />a slightly lower temperature (DTGmax = 72.35°C), which could indicate that the hydrogenbonding<br />system is a bit stronger in the final planar compound (form II, DTGmax = 80.14°C).<br />Additionally, the final compound has a slightly larger volume (>2.5%, 1262.8 Å3/mol) than the<br />first one (1228.3 Å3/mol), which could be related to the entropy of the systems. After the loss<br />of water, the TGA curves are not identical, which indicates that they do not evolve towards the<br />same compound upon heating. DFT calculations on the complex anion realized by Dr. Miguel<br />Baya García reveal a slight energetic advantage for the distorted conformation, from which<br />the conclusion is drawn that crystals of form II, which according to Ostwald's Rule of Stages<br />are more stable than those of form I, are energetically favored as a result of the hydrogen<br />bonding.<br />
000107707 520__ $$a<br />
000107707 521__ $$97081$$aPrograma de Doctorado en Química Inorgánica
000107707 6531_ $$acristalografia
000107707 6531_ $$aestructura cristalina
000107707 6531_ $$aquimica del estado solido
000107707 6531_ $$acompuestos coordinados
000107707 700__ $$a Lawrence Rocco Falvello$$edir.
000107707 700__ $$a Mohsen Graia$$edir.
000107707 7102_ $$aUniversidad de Zaragoza$$b
000107707 830__ $$9493
000107707 8560_ $$fcdeurop@unizar.es
000107707 8564_ $$s13009595$$uhttps://zaguan.unizar.es/record/107707/files/TESIS-2021-285.pdf$$zTexto completo (fra)
000107707 909CO $$ooai:zaguan.unizar.es:107707$$pdriver
000107707 909co $$ptesis
000107707 9102_ $$a$$b
000107707 980__ $$aTESIS