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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Using sterically hindered anionic N-donor ligands for stabilization of low-valent metal complexes

January 2015 (has links)
The present research work focuses on the coordination chemistry of two different types of monoanionic nitrogen-coordinating ligands, namely the bidentate triazenide ligand [(DippN)N(NDipp)]⁻ (Dipp = Prⁱ₂C₆H₃−2,6) (L¹) and monodentate arylamido ligands [N(R)(Ar)]⁻ (R = SiMe₃., Ar = C₆H₃Me₂-2,6 (L²), C₆H₂Me₃-2,4,6 (L³) or C₆H₃Prⁱ₂-2,6 (L⁴); R = SiBuᵗMe₂, Ar = C₆H₃Prⁱ₂-2,6 (L⁵)). The first part of this work was centred on the synthesis, structural characterization and reactivity of divalent lanthanide metal complexes derived from the triazenide ligand L¹. The second part of this work dealt with the chemistry of low valent and low-coordinate first row transition metal complexes supported by arylamido ligands Lⁿ (n = 2-5). The last part of this work focused on the synthesis and structures of divalent chromium complexes derived from the L¹, L⁴ and L⁵ ligands. / Chapter 1 presents an overview on divalent lanthanide complexes derived from nitrogen-coordinating ligands. The coordination chemistry of low valent and low-coordinate first-row transition metal complexes was also reviewed. / Chapter 2 describes the preparation and characterization of samarium(II) triazenide complex [Sm(L¹)₂(THF)₂] (2). Complex 2 was prepared by the reaction of SmI₂(THF)₂ with 2 equivalents of potassium triazenide [KL¹(THF)₀.₅] (1). The electrochemistry of 2 in THF was studied with cyclic voltammetry. Complex 2 is a strong reducing reagent. Its reactions with various inorganic/organic substrates have been examined. Treatment of 2 with AgCl or PhCH₂Cl gave Sm(III) bis(triazenide) chloride complex [Sm(L¹)₂Cl(THF)₂] (3), whilst reaction of 2 with I₂ led to the isolation of the iodide complex [Sm(L¹)I₂(THF)₃] (4). Reactions of 2 with PhEEPh (E = S, Se) afforded the corresponding Sm(III) chalcogenolate complexes [Sm(L¹)₂(EPh)(THF)] (E = S (5), Se (6)). On the other hands, addition of 2 to ArEEAr (Ar = Buᵗ₂C₆H₃−2,6, E = S, Se and Te) yielded the homoleptic Sm(III) tris(triazenide) complex [Sm(L¹)₃] (7) as the only isolable product. Besides, reactions of 2 with O₂, S₈, Se, Ph₃P=Se and BuᵗOOBuᵗ also yielded complex 7. Complex 2 reacted with PhNHNH₂ and PhNHNHPh, leading to the isolation of the corresponding Sm(III) phenylhydrazido complexes [Sm(L¹)₂(DMAP)₂(NH₂NPh)] (8) and [Sm(L¹)(THF)(μ-η²:η²-PhNNPh)]₂ (9). Reactions of 2 with azobenzene, benzophenone, 9-fluorenone, adamantyl azide, N, N’-dicyclohexylcarbodiimide, N, N’-diisopropylcarbodiimide, and CS₂ were examined as well. / Chapter 3 reports on the coordination chemistry of the triazenide ligand L¹ with divalent ytterbium and europium ions. Metathetical reaction of LnI₂(THF)₂ (Ln = Yb, Eu) with two molar equivalents of [Na(L¹)(THF)₃] (10) led to the corresponding divalent lanthanide(II) bis(triazenide) complexes [Eu(L¹)₂(THF)₂] (11) and [Yb(L¹)₂(THF)₂] (12). The heteroleptic ytterbium(II) complex [Yb(L¹)(μ-I)(THF)₂]₂.(C₆H₁₄) (13.C₆H₁₄) was also isolated along with 12. Oxidation of 12 with CuCl afforded Yb(III) triazenide−chloride complex [Yb(L¹)₂Cl(THF)₂] (14). Treatment of 12 with PhEEPh (E = S, Se) afforded the corresponding Yb(III) chalcogenolate complexes [Yb(L¹)₂(EPh)(THF)] (E = S (15), Se (16)). Nevertheless, reactions of 12 with elemental sulfur and selenium yielded the homoleptic Yb(III) complex [Yb(L¹)₃] (17) as the only isolable product. / Chapter 4 deals with the synthesis and characterization of low valent and low-coordinate first row transition metal complexes derived from arylamido ligands L²-L⁵. Reaction of MCl₂ (M = Fe, Co) with one molar equivalent of lithium amide [Li(L³)(TMEDA)] (TMEDA = Me₂NCH₂CH₂NMe₂) yielded the corresponding monoamido complexes [M(L³)Cl(TMEDA)] (M = Fe (20) and Co (22)). Reduction of [Co(L²)Cl(TMEDA)] (21), 22 and [Co(L³)Cl(TMEDA)] (23) with potassium metal gave the corresponding cobalt(I) amido complexes [CoL²]₂ (24), [CoL₃]₂ (25) and [CoL⁴]₂ (26), respectively. Meanwhile, treatment of [Fe(L⁴)Cl(TMEDA)] (23) with potassium metal yielded iron(I)-dinitrogen complex [{FeL⁴(TMEDA)}₂(μ-η¹:η¹-N₂)] (27). Complexes 24-27 were fully characterized by X-ray crystallography, various spectroscopic techniques and cyclic voltammetry. DFT calculations were carried out in order to understand the electronic structures of these complexes. / Chapter 5 describes the preparation and characterization of three neutral two-coordinate first row transition metal complexes of the general formula [M(L⁵)₂] (M = Fe (29), Co (30), Ni (31)). They were prepared by the reactions of anhydrous MCl₂ (M = Fe, Co) or NiBr₂(DME) with [LiL⁵(Et₂O)₂] (28). The solid-state structures of complexes 29-31 were determined by X-ray diffraction analysis. They were also characterized by spectroscopic methods (UV/Vis, I.R.) and electrochemistry. TD-DFT computational analysis was carried out in order to assign UV/Vis spectra features of these two-coordinate late transition metal (Fe->Ni) complexes. / Chapter 6 reports on the coordination chemistry of L¹, L⁴ and L⁵ with chromium ions. Treatment of CrCl₂ or CrCl₃ with one molar equivalent of [Li(L¹)(Et₂O)₂] (32) yielded heteroleptic Cr(II) complex [Cr(L¹)(μ-Cl)(THF)]₂ (33) and Cr(III) complex [Cr(L¹)Cl₂(THF)₂] (34), respectively. Attempts to reduce 33 and 34 with potassium metal, potassium graphite or magnesium were unsuccessful, yielding [Cr(L¹)₂] (35). Reaction chemistry of 35 was also studied in our research work. No reaction was observed in the reaction of 35 with PhEEPh (E = S, Se). Treatment of 35 with iodine led to the isolation of iodide bridged heteroleptic Cr(II) complex [Cr(L¹)(μ-I)(THF)]₂ (36). Simple monodentate amido ligands L⁴ and L⁵ were also used to prepare Cr(I) complexes. Treatment of anhydrous CrCl₂ with [LiL⁴(Et₂O)₀.₅] and [LiL⁵(Et₂O)₂] (28) afforded oxidative deprotonation products [Cr{N(C₆H₃Prⁱ₂-2,6)(SiMe₂CH₂)}₂Cr(L⁴)] (37) and [Cr(L⁵){N(C₆H₃Prⁱ₂-2,6)(SiBuᵗMeCH₂)}] (38). Attempts to synthesize monovalent chromium complexes supported by the L¹, L⁴ and L⁵ ligands were still in progress during the submission of this thesis. / Chapter 7 summarizes the results of the present studies. A brief description on the future direction of this research work is also presented. / 本項研究工作主要針對兩類負一价含氮配体,即雙齒叠氮基配体[(DippN)N(NDipp)]⁻ (Dipp = Prⁱ₂C₆H₃−2,6) (L¹)和單齒苯胺基配体[N(R)(Ar)]⁻ (R = SiMe₃, Ar = C₆H₃Me₂-2,6 (L²), C₆H₂Me₃-2,4,6 (L³) or C₆H₃Prⁱ₂-2,6 (L⁴); R = SiBuᵗMe₂, Ar = C₆H₃Prⁱ₂-2,6 (L⁵))的配位化學進行研究。本研究工作的第一部分致力於研究二價鑭系叠氮基配合物的合成,結構及其化學反應性。第二部分研究工作主要集中于由苯胺基構築的低價態,低配位數的第一周期后過渡金属的配位化學研究。最後一部分工作闡述了二價鉻叠氮基配合物和苯胺基配合物的合成,結構和表徵。 / 第一章概述了二價鑭系含氮配合物的發展。同時,也簡要闡述低價態,低配位數過鍍金属含氮配合物的研究工作。 / 第二章描述了二價釤叠氮基配合物[Sm(L¹)₂(THF)₂] (2)的製備,結構及其化學反應性。配合物2是由SmI₂(THF)₂與兩當量的鉀叠氮基化合物[KL¹(THF)₀.₅] (1) 反應製得。配合物2的電化學性質採用了循環伏安法進行了研究。介於配合物2為強還原劑,它與一系列無機/有機化合物的反應也予以探索。配合物2與AgCl或PhCH₂Cl反應得到了三價釤雙叠氮基氯化物[Sm(L¹)₂Cl(THF)₂](3),同時配合物2與單質碘I₂反應得到了碘化物[Sm(L¹)I₂(THF)₃] (4)。配合物2與二苯基硫族化合物PhSSPh及PhSeSePh反應得到了相應的三價釤硫族配合物[Sm(L¹)₂(EPh)(THF)](E = S (5), Se (6))。與之相反,配合物2與位阻較大的二苯基硫族化合物ArEEAr (Ar = Buᵗ₂C₆H₃−2,6, E = S, Se和Te)反應得到了均配的三價釤三叠氮基配合物[Sm(L¹)₃] (7)。此外,配合物2與O₂, S₈, Se, Ph₃P=Se和BuᵗOOBuᵗ反應都生成了配合物7。配合物2與苯肼化合物PhNHNH₂和PhNHNHPh反應得到了相應的三價釤苯肼配合物[Sm(L¹)₂(DMAP)₂(NH₂NPh)] (8) (DMAP = 對二甲基胺吡啶)以及[Sm(L¹)(THF)(μ-η²:η²-PhNNPh)]₂(9)。另外,本章對配合物2與偶氮苯;二苯基酮;9-芴酮;金剛烷叠氮化物;二環已基碳二亞胺;二異丙基碳二亞胺以及二硫化碳的反應性也進行了研究。 / 第三章講述了對該叠氮基配体L¹所衍生出的二價鐿和銪配合物的配位化學研究工作。二價鑭系碘化物LnI₂(THF)₂(Ln = Yb, Eu)與兩當量的鈉叠氮基化合物[Na(L¹)(THF)₃] (10)的複分解反應得到相應的二價鑭系雙叠氮基配合物[Eu(L¹)₂(THF)₂] (11)以及[Yb(L¹)₂(THF)₂] (12)。在製備二價鐿雙叠氮基配合物[Yb(L¹)₂(THF)₂] (12)的過程中同時得到了異配的二價鐿碘橋連單叠氮基配合物[Yb(L¹)(μ-I)(THF)₂]₂.(C₆H₁₄) (13.C₆H₁₄)。配合物12與CuCl的氧化反應得到三價鐿叠氮基氯化物[Yb(L¹)₂Cl(THF)₂] (14)。此外,配合物12與二苯基硫族化合物PhSSPh及PhSeSePh反應得到了相應的三價鐿硫族配合物[Yb(L¹)₂(EPh)(THF)] (E = S (15), Se (16))。然而,配合物12與單質硫和單質硒的反應生成唯一的產物,即均配的三價鐿三叠氮基配合物[Yb(L¹)₃] (17)。 / 第四章闡述了由苯胺基配体L²-L⁵所衍生的低價態,低配位數第一周期后過渡金屬的製備以及結構表徵。通過金屬氯化物MCl₂(M = Fe, Co)和一當量的鋰苯胺基化合物反應得到相應的二價鐡和鈷的單苯胺基配合物[M(L³)Cl(TMEDA)] (M = Fe (20) 和 Co (22))。配合物[Co(L²)Cl(TMEDA)] (21), 22和[Co(L³)Cl(TMEDA)] (23) 與金屬鉀的還原反應分別得到相應的一價鈷苯胺基配合物[CoL²]₂ (24), [CoL³]₂ (25) 和 [CoL⁴]₂ (26)。與此同時,二價鐡單苯胺基配合物[Fe(L⁴)Cl(TMEDA)] (23)與金屬鉀反應得到了一價鐡-偶氮配合物[{FeL⁴(TMEDA)}₂(μ-η¹:η¹-N₂)] (27)。配合物24-27的分子結構及其物理性質分別以X射綫衍射晶体學,波譜學以及循環伏安法表徵。密度泛函(DFT)這一理論計算方法也被用來瞭解這些配合物的電子結構。 / 第五章描述了三個二配位的第一周期后過渡金屬配合物[M(L⁵)₂] (M = Fe (29), Co (30), Ni (31))的製備和表徵。它們由相應的無水金屬鹵化物MCl₂ (M = Fe, Co)或NiBr₂(DME)與[LiL⁵(Et₂O)₂] (28)反應製得。配合物29-31的固體結構由X射綫衍射分析獲得。它們的光學性質和電學性質也分別由波譜方法(紫外可見光光譜,紅外光譜)以及循環伏安法表徵得到。含時密度泛函(TD-DFT)這一計算分析方法也被用來瞭解這些化合物紫外可見光光譜性質。此外,配合物31在有機烯烴與苯硅烷PhSiH3的硅氫化反應中被證實為有效的催化劑。 / 第六章講述了由配体L¹, L⁴與L⁵所構築的二價鉻的配位化學的研究。通過無水二氯化鉻CrCl₂或三氯化鉻CrCl₃與一當量的鋰叠氮基配合物[Li(L¹)(Et₂O)₂] (32)反應分別成功製備了相應的異配的二價鉻配合物[Cr(L¹)(μ-Cl)(THF)]₂ (33) 以及三价鉻配合物[Cr(L¹)Cl₂(THF)₂] (34)。利用金屬鉀,鉀碳以及單質鎂來還原配合物33和34生成了二價鉻雙叠氮基配合物[Cr(L¹)₂] (35)。此外,配合物35的反應性能也在本項工作得以研究。然而,在配合物35與二苯基硫族化合物PhSSPh及PhSeSePh反應中並沒有觀察到明顯的反應變化,依舊得到了原料配合物35。配合物35與單質碘I₂反應得到了異配碘橋連二價鉻配合物[Cr(L¹)(μ-I)(THF)]₂ (36)。單齒苯胺基配体L⁴和L⁵也被嘗試用來合成一價鉻配合物。無水二氯化鉻CrCl2與鋰苯胺基化合物[LiL⁴(Et₂O)₀.₅]和[LiL⁵(Et₂O)₂] (28)反應分別生成了氧化脫質子產物[Cr{N(C₆H₃Prⁱ₂-2,6)(SiMe₂CH₂)}₂Cr(L⁴)] (37) and [Cr(L⁵){N(C₆H₃Prⁱ₂-2,6)(SiBuᵗMeCH₂)}] (38)。關於利用叠氮基配体L¹,以及苯胺基配体L⁴和L⁵來製備一價鉻配合物的相關工作在遞交本論文的過程中还在進行中。 / 第七章總結了本論文的研究成果,並對本項工作未來的發展作出了簡要的描述。 / Yun, Lei. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2015. / Includes bibliographical references. / Abstracts also in Chinese.80-30|aDetailed summary in vernacular field only. / Title from PDF title page (viewed on 21, December, 2016). / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.
162

A study of cobalt silicide formed by MEVVA implantation.

January 1999 (has links)
by Li Chi Pui. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves [105]-[109]). / Abstracts in English and Chinese. / Abstract / Acknowledgement --- p.Page no / Chapter Chapter 1. --- Introduction / Chapter 1.1 --- Metal silicides --- p.1 / Chapter 1.2 --- Cobalt silicides --- p.3 / Chapter 1.3 --- Ion beam synthesis of metal silicides by metal implantation into silicon --- p.4 / Chapter 1.4 --- Feature of MEVVA implantation --- p.5 / Chapter 1.5 --- Motivation and organisation of this thesis --- p.6 / Chapter Chapter 2. --- Sample Preparation and Characterisation Methods / Chapter 2.1 --- MEVVA implantation --- p.7 / Chapter 2.2 --- Simulation by TRIM --- p.9 / Chapter 2.3 --- Sample preparation --- p.12 / Chapter 2.4 --- Sheet resistivity measurements --- p.14 / Chapter 2.5 --- Rutherford backscattering spectroscopy (RBS) --- p.17 / Chapter 2.6 --- Transmission electron microscopy (TEM) --- p.19 / Chapter 2.6.1 --- Transmission electron microscopy (TEM) sample preparation --- p.21 / Chapter 2.7 --- Atom force microscopy (AFM) and conducting AFM --- p.31 / Chapter Chapter 3. --- Characterisation of As-implanted Samples / Chapter 3.1 --- Experimental details / Chapter 3.1.1 --- Sheet resistance measurements --- p.33 / Chapter 3.1.2 --- Rutherford backscattering spectroscopy (RES) --- p.36 / Chapter 3.1.3 --- Sputtering depth measurements --- p.43 / Chapter 3.1.4 --- Transmission electron microscopy (TEM) --- p.44 / Chapter 3.1.5 --- Spreading resistance profiling (SRP) --- p.61 / Chapter 3.1.6 --- Atom force microscopy (AFM) and conducting AFM --- p.64 / Chapter 3.2 --- Results and discussion --- p.71 / Chapter 3.3 --- Summary --- p.81 / Chapter Chapter 4. --- Characterisation of Annealed Samples / Chapter 4.1 --- Experimental details / Chapter 4.1.1 --- Rutherford backscattering spectroscopy (RBS) --- p.82 / Chapter 4.1.2 --- Transmission electron microscopy (TEM) --- p.87 / Chapter 4.1.3 --- Sheet resistance measurements --- p.98 / Chapter 4.2 --- Summary --- p.101 / Chapter Chapter 5. --- Conclusion --- p.102 / Appendix / Reference
163

Synthesis and structural characterization of amido- and imido-lanthanide compounds.

January 2000 (has links)
by Chan Hoi Shan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 111-119). / Abstracts in English and Chinese. / Acknowledgement --- p.iii / Abbreviation --- p.iv / List of Compounds --- p.vi / Abstract --- p.vii / Abstract (Chinese) --- p.ix / Chapter Chapter 1. --- Introduction / Chapter 1.1 --- Lanthanide-Amine Compounds --- p.1 / Chapter 1.2 --- Lanthanide-Amide Compounds --- p.3 / Chapter 1.3 --- Lanthanide-Imide Compounds --- p.11 / Chapter 1.4 --- Some Applications of Lanthanide-Amide Compounds in Organic Synthesis --- p.15 / Chapter 1.5 --- Aims --- p.19 / Chapter Chapter 2. --- Synthesis and Structural Characterization of Anionic and Neutral Dichlorolanthanocene Compounds / Chapter 2.1 --- Synthesis --- p.20 / Chapter 2.2 --- Structural Characterization --- p.22 / Chapter 2.3 --- Conclusion --- p.23 / Chapter Chapter 3. --- Synthesis and Structural Characterization of Amido-Lanthanide Compounds / Chapter 3.1 --- Synthesis and Structural Characterization of Yb(NHAr)3(THF)n --- p.26 / Chapter 3.2 --- "Synthesis and Structural Characterization of Yb(NHC6H3iPr2- 2,6)4Na(THF)" --- p.38 / Chapter 3.3 --- "Synthesis and Structural Characterization of Yb(Cp"")(NHAr)2(L)" --- p.45 / Chapter 3.4 --- "Synthesis and Structural Characterization of Yb(Cp"")(NHC6H3iPr2- 2,6)3M(L)" --- p.54 / Chapter 3.5 --- Synthesis and Structural Characterization of Yb(NHAr)3(NH2Ar)(L) --- p.74 / Chapter 3.6 --- Conclusion --- p.76 / Chapter Chapter 4. --- Synthesis and Structural Characterization of Imido-Lanthanide Compounds / Chapter 4.1 --- Synthesis --- p.81 / Chapter 4.2 --- Structural Characterization --- p.82 / Chapter 4.3 --- Conclusion --- p.85 / Chapter Chapter 5. --- Summary and Remarks / Chapter 5.1 --- Summary --- p.96 / Chapter 5.2 --- Remarks --- p.97 / Chapter Chapter 6. --- Experimental Section --- p.98 / References --- p.111 / Appendix --- p.120
164

Formation and characterization of cobalt silicide by MEVVA implantation. / CUHK electronic theses & dissertations collection

January 1997 (has links)
by Peng Qicai. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / includes bibliographical references (p. 187-206). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.
165

Synthesis, molecular structure and reactivity studies of organolanthanide Fluoride and Carborane compounds. / CUHK electronic theses & dissertations collection

January 2000 (has links)
Kwoli Chui. / "August 2000." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (p. 122-140). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
166

Synthesis and structures of lanthanide metal amides.

January 2001 (has links)
by Kui Chi Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references. / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstracts --- p.ii / Table of Contents --- p.v / Abbreviations --- p.viii / Chapter CHAPTER 1. --- METALLATION OF AMINOPYRIDINE AND AMINOQUINOLINE / Chapter 1.1 --- INTRODUCTION --- p.1 / Chapter 1.1.1 --- General Background --- p.1 / Chapter 1.1.2 --- A Brief Review on Sodium and Potassium Amides --- p.3 / Chapter 1.1.3 --- Preparation of Sodium and Potassium Amides --- p.8 / Chapter 1.2 --- RESULTS AND DISCUSSION --- p.10 / Chapter 1.2.1 --- "Synthesis of [NH(SiButMe2)(R)] [ R = 2-C5H3N-6-Me, 8-C9H6N ] as Ligand Precursors" --- p.10 / Chapter 1.2.2 --- Synthesis of Sodium and Potassium Amido Complexes Containing the Pyridine-Functionalized Amido Ligand [N(SiButMe2)(2-C5H3N-6-Me)]- --- p.11 / Chapter 1.2.2.1 --- Sodium Pyridyl Amido Complexes --- p.11 / Chapter 1.2.2.2 --- Potassium Pyridyl Amido Complexes --- p.12 / Chapter 1.2.3 --- Synthesis of Sodium and Potassium Amido Complexes Containing the Quinoline-Functionalized Amido Ligand [N(SiButMe2)(8-C9H6N)]- --- p.15 / Chapter 1.2.3.1 --- Sodium Quinolyl Amido Complexes --- p.15 / Chapter 1.2.3.2 --- Potassium Quinolyl Amido Complexes --- p.16 / Chapter 1.2.4 --- Physical Characterization of Compounds 3-9 --- p.17 / Chapter 1.2.5 --- "Molecular Structures of Compounds 3, 5 and 7" --- p.20 / Chapter 1.3 --- EXPERIMENTALS FOR CHAPTER 1 --- p.30 / Chapter 1.3 --- REFERENCES FOR CHAPTER 1 --- p.36 / Chapter CHAPTER 2. --- "Synthesis,Structures, and Catalytic Properties of Lanthanide Metal Amides Containing the Pyridine - Functionalized Amido Ligand [N(SiButMe2)(2-C5H3N-6-Me)]-" / Chapter 2.1 --- INTRODUCTION --- p.39 / Chapter 2.1.1 --- General Background --- p.39 / Chapter 2.1.2 --- A Brief Review on Rare Earth Amido Complexes --- p.40 / Chapter 2.1.3 --- General Preparation Methods to Lanthanide Metal Amides --- p.44 / Chapter 2.1.4 --- Ring-Opening Polymerization of Lactones --- p.45 / Chapter 2.1.5 --- Objectives of This Work --- p.48 / Chapter 2.2 --- RESULTS AND DISCUSSION --- p.49 / Chapter 2.2.1 --- Synthesis and Physical Properties --- p.49 / Chapter 2.2.1.1 --- Homoleptic Lanthanide Metal Amides 10-18 --- p.49 / Chapter 2.2.1.2 --- Heteroleptic Lanthanide Metal Amides 19-22 --- p.53 / Chapter 2.2.2 --- Molecular Structures --- p.56 / Chapter 2.2.2.1 --- Molecular Structures of Homoleptic Lanthanide Metal Amides 10-18 --- p.56 / Chapter 2.2.2.2 --- Molecular Structures of Heteroleptic Lanthanide Metal Amides 19-22..… --- p.76 / Chapter 2.2.3 --- Reactivity Studies --- p.89 / Chapter 2.2.3.1 --- "Reaction with 3,5-di-tert-butylcatechol (dbcH2)" --- p.89 / Chapter 2.2.3.2 --- Ring-Opening Polymerization of s-Caprolactone --- p.95 / Chapter 2.3 --- EXPERIMENTALS FOR CHAPTER 2 --- p.100 / Chapter 2.4 --- REFERENCES FOR CHAPTER 2 --- p.108 / Chapter CHAPTER 3. --- Preparation of Pyridine Adducts of Zinc(II) Chloride and Low-coordinate Zinc(II) Dithiolate and Bis(aryloxide) Compounds / Chapter 3.1 --- INTRODUCTION --- p.111 / Chapter 3.1.1 --- General Background --- p.111 / Chapter 3.2 --- RESULTS AND DISCUSSION --- p.115 / Chapter 3.2.1 --- Synthesis of Pyridine Adducts of Zinc(II) Chloride --- p.115 / Chapter 3.2.2 --- Synthesis of Novel Three-Coordinate Zinc(II) Dithiolate and Bis(aryloxide) --- p.116 / Chapter 3.2.3 --- Physical Characterization of Compounds 23-26 --- p.118 / Chapter 3.2.4 --- Molecular Structures of Compounds 23-25 --- p.122 / Chapter 3.3 --- EXPERIMENTALS FOR CHAPTER 3 --- p.129 / Chapter 3.4 --- REFERENCES FOR CHAPTER 3 --- p.133 / Chapter CHAPTER 4. --- Summary of this Research Work --- p.135 / Appendix 1 General Procedures and Physical Measurements --- p.137 / "Appendix 2 Table A-l. Selected Crystallographic Data for Compounds 3, 5,7,10 and 11" --- p.139 / Table A-2. Selected Crystallographic Data for Compounds12-16 --- p.140 / Table A-3. Selected Crystallographic Data for Compounds17-21 --- p.141 / Table A-4. Selected Crystallographic Data for Compounds22-25 --- p.142
167

Synthesis and reactivity of early transition metal complexes containing multiple metal to carbon, nitrogen, or oxygen bonds

Rocklage, Scott M January 1982 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE / Vita. / Includes bibliographical references. / by Scott M. Rocklage. / Ph.D.
168

Synthesis and structural survey of novel rare earth aryloxide and pyrazolate complexes

Gitlits, Alexander, 1975- January 2001 (has links)
Abstract not available
169

Mössbauer spectroscopy on selectred magnetic compounds

Kalska-Szostko, Beata January 2000 (has links)
<p>The applications of magnetic materials are related to their magnetic and crystal structure as well as electronic properties. In this thesis, mainly experimental methods have been focussed on novel materials and bulk materials. A selection of materials were studied by several techniques like Mössbauer spectroscopy, X-ray and neutron diffraction and magnetisation measurements.</p><p>New technology allow us to prepare artificial materials with unic magnetic properties. Magnetic multilayers are very interesting not only from phenomenological point of view but also as good applications materials. In this work will be shown some results from Fe/V and Fe/Co multilayer system</p><p>The (Fe<sub>1-x</sub>Mn<sub>x</sub>)<sub>3</sub>P system has been studied at both ends of the composition range. At the Fe-rich end, compounds exhibiting ferromagnetic ordering are formed, while at the Mn-rich end, an antiferromagnetic coupling was discovered. The experimental results are supported by theoretical calculations.</p><p>Rare-earth compounds with focus on Fe<sub>0.65</sub>Er<sub>0.2</sub>B<sub>0.15</sub> were studied by means of traditional Mössbauer spectroscopy, Monochromatic Circular Polarized Mössbauer Spectroscopy, X-ray diffraction and magnetic mesurements. This compound shows interesting behaviour of Fe magnetic moment at low and room temperature.</p><p>The first magnetic studies on rhombohedral Li<sub>3</sub>Fe<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub> at low temperature has also been made and an antiferromagnetic structure was revealed.</p>
170

Tunable Magnetic Properties of Transition Metal Compounds

Felton, Solveig January 2005 (has links)
<p>The magnetic properties of transition metal compounds have been studied using SQUID-magnetometry, magnetic force microscopy and Lorentz transmission electron microscopy. New magnetic materials have been found and their magnetic properties have been determined. How the magnetic properties of a material can be changed through e.g. chemical substitution of magnetic and nonmagnetic atoms and shape and size effects have also been studied. Three different sets of samples have been investigated: three new Mn-compounds, two substitution series of layered magnetic structures and ferromagnetic micronsized thin film elements.</p><p>The three Mn-compounds, Mn<sub>3</sub>IrSi, IrMnSi and Mn<sub>8</sub>Pd<sub>15</sub>Si<sub>7</sub>, show different magnetic ordering. Mn<sub>3</sub>IrSi orders 'antiferromagnetically' at 210 K. IrMnSi forms a double cycloidal spin spiral below 460 K. Mn<sub>8</sub>Pd<sub>15</sub>Si<sub>7</sub> only shows short-range magnetic ordering.</p><p>Substituting Se with S in TlCo<sub>2</sub>Se<sub>2-x</sub>S<sub>x</sub> changes the magnetic order from a spin spiral to a colinear ferromagnet for a composition of <i>x</i>=1.75. An intermediate region exists where the compound is neither a pure ferromagnet, nor purely a spin spiral, as evidenced by the magnetization versus field measurements for the <i>x</i>=1.3 and 1.5 samples. This is also seen in the temperature dependent susceptibility measurements. For the TlCu<sub>2-x</sub>Fe<sub>x</sub>Se<sub>2</sub> compounds it was found that the ordering temperature and saturation magnetic moment per Fe-atom changed with composition <i>x</i>.</p><p>Ferromagnetic micronsized thin film elements in permalloy, Fe<sub>20</sub>Ni<sub>80</sub>, and epitaxial Fe/Co multilayers were studied. For the Fe/Co multilayer thin film elements it was found that it is possible to change the magnetization reversal process, by aligning the easy shape anisotropy axis with either the easy or the hard magnetocrystalline anisotropy axis. In the permalloy elements the effect of inter-elemental distance was found to determine the interval of fields where multidomain states were stable, so that for shorter inter-elemental distances multidomain states were stable for a shorter interval of fields. The domain structure of permalloy elements in rotating magnetic fields was also studied. Higher applied fields led to a broader interval of angles in which saturated states were stable.</p>

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