Silicon holds a privileged position in organic chemistry as the carbon-silicon bond can be utilised in many important transformations. As such, developing practical and efficient methods for the enantioselective and regioselective insertion of silicon into organic molecules is a worthy challenge in chemical synthesis. To this end, we have developed an affordable copper-catalysed protocol for the asymmetric silylation of lactones, lactams and amides, providing silylated products with up to > 99:1 er and in good yields. Furthermore, we have demonstrated the synthetic utility of this protocol in the target synthesis of natural or biologically active molecules. We also present the first copper-catalysed silylation of allenes using a silylborane reagent. This affords useful allyl- or vinylsilane building blocks with high regioselectivity, efficiency and a large functional group tolerance. The allylcopper intermediates can be intercepted by aldehydes in a diastereoselective three-component coupling to furnish homoallylic alcohols. We extend this concept to the copper-catalysed three-component coupling of boron, allenes and imines, providing access to homoallylic amines with a vinylborane motif.

氟硼熒二吡咯染料是一類多功能的熒光材料，並得到了廣泛的應用。本論文的目標是探索此類染料以及它的氮雜類似物作為探測重金屬離子的熒光探針，非線性光學材料和構建人工光合作用模型的潛力。 本論文報導了一系列氟硼熒二吡咯染料和它的氮雜類似物的分子設計，合成，光學性質以及在相關領域的應用。 / 第一章簡單的概述了氟硼熒二吡咯染料的合成，光學性質和作為重金屬熒光探針和非線性光學材料的應用。然後詳細概述了氮雜氟硼熒二吡咯染料的發展，合成，光學性質，以及其在生物醫藥和材料科學領域的潛在應用。 / 第二章報導了一個對銅和汞二價離子具有高選擇性比色性識別的近紅外熒光探針。 這個探針以雙邊苯乙烯修飾的氟硼熒二吡咯染料為螢光團，並進一步修飾兩個二（三唑）胺的識別位點。在體積比為1 比1 的乙腈水溶液中，當加入銅和汞二價離子時，這個探針的吸收和熒光波長表現出不同程度的藍移，而且這個變化可以被肉眼觀察到。這是因為分子內的電荷傳遞過程被抑制的結果。另外，通過其熒光變化的工作曲線法，銅二價離子與此探針具有2 比1 的結合比例。進一步研究表明它們表現出較大的結合常數（(6.2 ± 0.6) × 10⁹ M⁻²），是汞二價離子的結合常數的六倍。 / 另外，除了分子內電荷傳遞的機理，光致電子轉移和熒光共振能量傳遞也是兩種常用的設計熒光探針的機理。第三章報導了兩個基於光致電子轉移和熒光共振能量傳遞的有高效選擇性的汞二價離子熒光探針。 我們使用電子吸收和熒光光譜的方法研究了他們之間的結合性能。其中一個探針在中間的位置連接了一個二（三唑）胺的結合位點，並對汞二價離子表現出很高的响應性。另一個探針進一步引入了兩個羅丹明熒光團到氟硼熒二吡咯染料上，於是當接觸到汞二價離子時，激發的氟硼熒二吡咯染料的能量將高效的傳遞到羅丹明上，從而表現出顯著的光譜的變化。 / 第四章描述了一系列含有兩個電子供體和推拉結構的氟硼熒以及氮雜氟硼熒二吡咯染料的設計，合成，以及作為非線性光學材料的潛力。通過薗頭偶合反應，兩個對位二苯胺基苯乙炔基或對位二甲氨基苯乙炔基被連接到了該染料的2 和6 位上。線性的吸收和熒光研究表明那些化合物表現出溶劑效應。 它們在甲苯中雙光子吸收的性能通過用雙光子激發熒光光譜的方法進行了研究。另外，對於推拉電子的一系類化合物，推電子的對位二甲氨基苯乙炔基和拉電子的對位硝基苯乙炔基分別連接到了該染料的2 和6 位上。這些化合物的光學和電化學性能得到了詳細的研究。在氯仿溶液中，它們的二價非線性光學性質通過電場誘導的二次諧波的方法進行了研究，其在1907 納米的標量積μ.β在94 ×10⁻⁴⁸ 到330 × 10⁻⁴⁸ esu 之間，並隨著3 和5 位取代基的不同而變化。 / 第五章報導了一個基於單邊苯乙烯氟硼熒二吡咯染料和富勒烯雙修飾的氮雜氟硼熒二吡咯染料的人工光合作用模型。這個三元體系的分子內光誘導的過程使用穩態的光學方法進行了研究。當激發單邊苯乙烯氟硼熒二吡咯染料部分時，這個被激發的部分會將能量傳遞給氮雜氟硼熒二吡咯染料，然後進一步的將電子傳遞給富勒烯。運用飛秒瞬態鐳射的方法，它們之間在苯睛中電子重排的速率是7.00 × 10⁸ s⁻¹，從而得到電荷分離態的壽命是1.47 納秒。 / 作為上一個工作的拓展，第六章報導了兩個或四個甲基化環糊精修飾的氮雜氟硼熒二吡咯染料與四磺酸基卟啉和其鋅卟啉，以及兩個帶正電的單邊苯乙烯修飾的氟硼熒二吡咯染料在水中的相互作用。使用各種光學方法，我們研究了它們的結合過程以及能量或者電子的傳遞過程。最後，四磺酸基卟啉， 環糊精修飾的氮雜氟硼熒二吡咯染料，以及單邊修飾的氟硼熒二吡咯染料在水溶液中進行了自組裝。當激發卟啉時，能量高效的傳遞到氮雜氟硼熒二吡咯染料上，接著電子從單邊修飾的氟硼熒染料傳遞到氮雜氟硼熒二吡咯染料上。因此，這個多重的超分子體系是一個很好的光合作用模型。 / 第七章和第八章分別闡述了前面幾章的實驗部分和引用文獻。 / 論文的最後一部分附上了所有新化合物的核磁共振氫譜和碳譜圖。 / Boron dipyrromethenes (BODIPYs) are versatile functional materials for a wide range of applications. This research work aims to explore the potential of these compounds and their aza analogues as fluorescent probes for heavy metal ions, nonlinear optical materials, and building blocks of artificial photosynthetic models. This thesis describes the molecular design, synthesis, spectroscopic characterization, and photophysical properties of several series of BODIPYs and aza-BODIPYs, as well as their potential applications in these areas. / Chapter 1 gives a brief overview of BODIPYs, focusing on their synthesis, spectroscopic properties, and applications as fluorescent probes for heavy metal ions and nonlinear optical materials. It then reviews the historical development, syntheses, and spectroscopic properties of their aza analogues. The potential applications of aza-BODIPYs in biomedicine and materials science are also discussed at the end of this chapter. / In Chapter 2, a highly selective colorimetric and near-infrared fluorescent probe for Cu²⁺ and Hg²⁺ ions is reported, which is based on a distyryl BODIPY with two bis(1,2,3-triazole)amino receptors. The compound selectively binds to Cu²⁺ and Hg²⁺ ions in CH₃CN/H₂O (1:1 v/v) giving remarkably blue-shifted electronic absorption and fluorescence bands as a result of inhibition of the intramolecular charge transfer (ICT) process upon binding. The color changes can be easily seen by the naked eye. The binding stoichiometry between this probe and Cu²⁺ ion has been determined to be 1:2 by a Job’s plot of the fluorescence data with a binding constant of (6.2 ± 0.6) × 10⁹ M⁻². The corresponding value for Hg²⁺ ion is about six-fold smaller. / In addition to the ICT mechanism, photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) are another two useful mechanisms for design of fluorescent probes. Chapter 3 reports two highly selective and sensitive BODIPY-based fluorescent probes for Hg²⁺ ion based on PET and FRET mechanisms. Their binding properties have been investigated by using electronic absorption and steady-state fluorescence spectroscopic methods. The probe with a bis(1,2,3-triazole)amino receptor at the meso position is highly responsive toward Hg²⁺ ion. By introducing two rhodamine B moieties to the BODIPY core, FRET occurs from the excited BODIPY to rhodamine B in a highly effective manner upon binding to Hg²⁺ ion, regarding to remarkable spectral changes. / Chapter 4 presents a series of BODIPY and aza-BODIPY derivatives bearing a donor-π-donor or push-pull structure as nonlinear optical materials. The donor-π-donor derivatives have been prepared by connecting 4-(diphenylamino)phenylethynyl or 4-(dimethylamino)phenylethynyl moieties to the 2- and 6-positions of the π systems through Sonogashira coupling reactions. The linear optical absorption and fluorescence properties of these compounds have been found to be solvent-dependent. Their two-photon absorption properties have also been measured in toluene by two-photon fluorescence excitation method. For the push-pull series, an electron-donating 4-(dimethylamino)phenylethynyl group and an electron-withdrawing 4-nitrophenylethynyl group have been added to the 2- and 6-positions of the BODIPY core. The spectroscopic and electrochemical properties of these compounds have been studied. Their second-order nonlinear optical properties have also been examined by electric-field-induced second-harmonic generation method in CHCl₃. The values of the dot product μ.β are in the range from 94 × 10⁻⁴⁸ to 330 × 10⁻⁴⁸ esu at 1907 nm, depending on the substituents at the 3- and 5-positions. / Chapter 5 describes the synthesis and characterization of an artificial photosynthetic model in which an aza-BODIPY core is covalently linked to a monostyryl BODIPY component and a fullerene (C₆₀) unit. The photoinduced intramolecular processes of this triad and the model compounds have been studied in detail by steady-state and time-resolved spectroscopic methods. Upon excitation at the monostyryl BODIPY moiety, excitation energy transfer occurs to the aza-BODIPY core, which is followed by an electron transfer to the C₆₀ unit. From the femtosecond transient absorption studies, the rate constant of charge recombination has been determined to be 7.00 × 10⁸ s⁻¹ in benzonitrile, giving a lifetime of 1.47 ns for the charge-separated state. / As an extension, Chapter 6 presents related supramolecular systems in which an aza-BODIPY derivative bearing two or four permethylated β-cyclodextrin moieties binds to metal-free and zinc(II) tetrasulfonated porphyrins, as well as two cationic monostyryl BODIPYs in water. The complexation of these components has been studied by various spectroscopic methods. The resulting host-guest complexes exhibit efficient energy and/or electron transfer depending on the nature of the guests. A novel mixed array of metal-free porphyrin, aza-BODIPY, and monostyryl BODIPY has also been assembled. Upon excitation at the porphyrin unit, singlet-singlet energy transfer occurs to the aza-BODIPY core, which then obtains an electron from the monostyryl BODIPY moieties. This supramolecular hetero-array thus also serves as an artificial photosynthetic model. / Chaper 7 gives the experimental details for the work described in the preceedingchapters. All the references cited herein are given in Chapter 8. / ¹H and ¹³C{¹H} NMR spectra of all the new compounds are given in the Appendix. / 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. / Detailed summary in vernacular field only. / Shi, Wenjing. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 204-220). / Abstracts also in Chinese. / Table of Contents --- p.I / Acknowledgment --- p.VII / Abstract --- p.IX / Abstract (in Chinese) --- p.XIII / Abbreviations --- p.XV / List of Figures --- p.XXI / List of Tables --- p.XXXII / List of Schemes --- p.XXXIV / Publication Related to This Thesis --- p.XXXVI / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- General --- p.1 / Chapter 1.2 --- Synthesis, Reactivity, and Spectroscopic Properties of BODIPYs --- p.2 / Chapter 1.2.1 --- Synthesis of BODIPYs --- p.2 / Chapter 1.2.2 --- Reactivity of BODIPYs --- p.5 / Chapter 1.2.3 --- Spectroscopic Properties of Selected BODIPYs --- p.6 / Chapter 1.3 --- Applications of BODIPYs --- p.9 / Chapter 1.3.1 --- BODIPYs as Fluorescent Probes for Heavy Metal Ions --- p.9 / Chapter 1.3.2 --- BODIPYs as Two-Photon Absorbing Materials --- p.14 / Chapter 1.3.2.1 --- General for Two-Photon Absorption --- p.14 / Chapter 1.3.2.2 --- Selected Examples of TPA Materials --- p.15 / Chapter 1.4 --- Aza-BODIPYs: Aza Analogues of BODIPYs --- p.18 / Chapter 1.4.1 --- General --- p.18 / Chapter 1.4.2 --- Synthesis and Reactivity of Aza-BODIPYs --- p.18 / Chapter 1.4.3 --- Spectroscopic Properties of Aza-BODIPYs --- p.21 / Chapter 1.4.4 --- Applications of Aza-BODIPYs --- p.29 / Chapter 1.4.4.1 --- Aza-BODIPYs as Artificial Photosynthetic Models --- p.29 / Chapter 1.4.4.2 --- Aza-BODIPYs as Fluorescent Probes --- p.33 / Chapter 1.4.4.3 --- Aza-BODIPYs as Photosensitizers and Imaging Probes --- p.37 / Chapter 1.4.4.4 --- Other Applications --- p.39 / Chapter 1.5 --- Objectives of this Study --- p.41 / Chapter Chapter 2 --- A Highly Selective Colorimetric and Fluorescent Probe for Cu²⁺ and Hg²⁺ Ions Based on a Distyryl BODIPY with Two Bis(1,2,3-triazole)amino Receptors / Chapter 2.1 --- Introduction --- p.42 / Chapter 2.2 --- Results and Discussion --- p.43 / Chapter 2.2.1 --- Synthesis and Characterization --- p.43 / Chapter 2.2.2 --- Metal Sensing Properties --- p.46 / Chapter 2.2.3 --- Binding Properties --- p.48 / Chapter 2.2.3.1 --- Binding Properties of 2.10 with Cu²⁺ Ion --- p.48 / Chapter 2.2.3.2 --- Binding Properties of 2.10 with Hg²⁺ Ion --- p.52 / Chapter 2.3 --- Conclusion --- p.55 / Chapter Chapter 3 --- Detection of Hg²⁺ Ion with BODIPY-Based Fluorescent Probes Substituted with a Bis(1,2,3-triazole)amino Receptor / Chapter 3.1 --- Introduction --- p.56 / Chapter 3.2 --- Results and Discussion --- p.57 / Chapter 3.2.1 --- Molecular Design, Synthesis, and Characterization --- p.58 / Chapter 3.2.2 --- Metal Binding Properties of 3.6 --- p.61 / Chapter 3.2.3 --- Metal Binding Properties of 3.7 --- p.66 / Chapter 3.2.4 --- Fluorescence Resonance Energy Transfer in 3.7 --- p.72 / Chapter 3.3 --- Conclusion --- p.73 / Chapter Chapter 4 --- Synthesis and Nonlinear Optical Properties of BODIPY and Aza-BODIPY Derivatives / Chapter 4.1 --- Introduction --- p.74 / Chapter 4.2 --- Results and Discussion --- p.75 / Chapter 4.2.1 --- Synthesis of D-π-D BODIPY and Aza-BODIPY Derivatives --- p.75 / Chapter 4.2.2 --- Synthesis of Push-Pull BODIPY Derivatives --- p.81 / Chapter 4.2.3 --- Linear Electronic Absorption and Fluorescence Properties of D-π-D BODIPY and Aza-BODIPY Derivatives --- p.84 / Chapter 4.2.4 --- Electrochemical Properties of D-π-D BODIPY Derivatives --- p.88 / Chapter 4.2.5 --- Two-Photon Absorption Properties of D-π-D BODIPY and Aza-BODIPY Derivatives --- p.90 / Chapter 4.2.6 --- Linear Electronic Absorption and Fluorescence Properties of Push-Pull BODIPY Derivatives --- p.93 / Chapter 4.2.7 --- Electrochemical Properties of Push-Pull BODIPY Derivatives --- p.96 / Chapter 4.2.8 --- Second-Order Nonlinear Optical Properties of Push-Pull BODIPY Derivatives --- p.97 / Chapter 4.3 --- Conclusion --- p.99 / Chapter Chapter 5 --- Photosynthetic Antenna-Reaction Center Mimicry with a Covalently Linked Monostyryl Boron Dipyrromethene-Aza Boron Dipyrromethene-C₆₀ Triad / Chapter 5.1 --- Introduction --- p.101 / Chapter 5.2 --- Results and Discussion --- p.103 / Chapter 5.2.1 --- Synthesis --- p.103 / Chapter 5.2.2 --- Steady-State Electronic Absorption and Fluorescence Properties --- p.105 / Chapter 5.2.3 --- Electrochemical Properties and Energy Levels --- p.109 / Chapter 5.2.4 --- Transient Absorption Studies --- p.112 / Chapter 5.2.4.1 --- Femtosecond Transient Absorption Studies --- p.112 / Chapter 5.2.4.2 --- Nanosecond Transient Absorption Studies --- p.117 / Chapter 5.2.5 --- Energy-Level Diagrams --- p.119 / Chapter 5.3 --- Conclusion --- p.121 / Chapter Chapter 6 --- Formation and Photoinduced Processes of the Host-Guest Complexes of β-Cyclodextrin-Conjugated Aza-BODIPYs with Tetrasulfonated Porphyrins and Monostyryl BODIPYs / Chapter 6.1 --- Introduction --- p.122 / Chapter 6.2 --- Results and Discussion --- p.123 / Chapter 6.2.1 --- Synthesis and Characterization --- p.123 / Chapter 6.2.2 --- Host-Guest Complexes of 6.3 with Tetrasulfonated Porphyrins --- p.131 / Chapter 6.2.3 --- Host-Guest Complexes of 6.7 with Tetrasulfonated Porphyrins --- p.141 / Chapter 6.2.4 --- Host-Guest Complexes of 6.7 with Monostyryl BODIPYs --- p.146 / Chapter 6.2.5 --- Host-Guest Complexes of 6.7 with Tetrasulfonated Porphyrins and Monostyryl BODIPYs --- p.154 / Chapter 6.3 --- Conclusion --- p.159 / Chapter Chapter 7 --- Experimental Section / Chapter 7.1 --- General --- p.160 / Chapter 7.2 --- Experiments in Chapter 2 --- p.162 / Chapter 7.2.1 --- Synthesis --- p.162 / Chapter 7.2.2 --- Absorption and Fluorescence Studies --- p.164 / Chapter 7.2.3 --- Determination of Binding Constants (K) --- p.165 / Chapter 7.3 --- Experiments in Chapter 3 --- p.165 / Chapter 7.3.1 --- Synthesis --- p.165 / Chapter 7.3.2 --- Absorption and Fluorescence Studies --- p.169 / Chapter 7.3.3 --- Determination of Binding Constants (K) --- p.169 / Chapter 7.4 --- Experiments in Chapter 4 --- p.170 / Chapter 7.4.1 --- Synthesis --- p.170 / Chapter 7.4.2 --- Electrochemical Measurements --- p.188 / Chapter 7.4.3 --- NLO Measurements --- p.188 / Chapter 7.5 --- Experiments in Chapter 5 --- p.190 / Chapter 7.5.1 --- Synthesis --- p.190 / Chapter 7.5.2 --- Electrochemical Measurements --- p.196 / Chapter 7.5.3 --- Time-Resolved Transient Absorption Measurements --- p.196 / Chapter 7.6 --- Experiments in Chapter 6 --- p.198 / Chapter 7.6.1 --- Synthesis --- p.198 / Chapter 7.6.2 --- Determination of Binding Constants (K) --- p.201 / Chapter 7.6.3 --- Molecular Dynamic Simulation --- p.202 / Chapter 7.6.4 --- Electrochemical Measurements --- p.203 / Chapter Chapter 8 --- References --- p.204 / Appendix --- p.221

Wang, Yang. / "October 2011." / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 87-92). / Abstracts in English and Chinese. / Acknowledgement --- p.I / Abstract (in English) --- p.III / Abstract (in Chinese) --- p.IV / Abbreviation --- p.V / List of Compounds --- p.VI / List of Figures --- p.IX / Contents --- p.X / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Synthesis and Structure of Half-Sandwich Group 4 Metallocarboranes Containing the Dicarbollyl Ligand --- p.2 / Chapter 1.2 --- Half-Sandwich Group 4 Metallacarboranes Catalyzed Reactions --- p.20 / Chapter 1.2.1 --- Polymerization of Olefins --- p.20 / Chapter 1.2.2 --- Catalytic Dimerization and Hydrogenation of Alkynes --- p.22 / Chapter 1.2.3 --- Catalytic Addition of Amines to Carbodiimides --- p.23 / Chapter 1.2.4 --- Catalytic Transamination of Guanidines --- p.24 / Chapter 1.2.5 --- Catalytic Synthesis of A^-Heterocycles --- p.25 / Chapter 1.3 --- Research Objectives of This Thesis --- p.26 / Chapter Chapter 2 --- Half-Sandwich Group 4 Metallacarborane Monoamindes --- p.27 / Chapter 2.1 --- Introduction --- p.27 / Chapter 2.2 --- Synthesis of Dicarbollyl Ligands Bearing Functional Side Arms --- p.27 / Chapter 2.3 --- Synthesis and Characterization of Half-Sandwich Group 4 Metallacarborane Monoamindes --- p.33 / Chapter 2.4 --- Summary --- p.43 / Chapter Chapter 3 --- Synthesis of 2-Aminoimidazoles Catalyzed by Half-Sandwich Titanacarborane Monoamide --- p.44 / Chapter 3.1 --- Introduction --- p.45 / Chapter 3.2 --- Known Methods for the Synthesis of 2-Aminoimidazole --- p.44 / Chapter 3.2.1 --- Condensations Methods --- p.44 / Chapter 3.2.2 --- Direct Introduction of N at C2 Position --- p.46 / Chapter 3.2.3 --- Heterocyclic Exchange Reactions --- p.47 / Chapter 3.2.4 --- Transition Metal Catalyzed Reactions --- p.48 / Chapter 3.3 --- Results and Discussion --- p.49 / Chapter 3.3.1 --- Synthesis of Propargy 1 Amines --- p.49 / Chapter 3.3.2 --- Synthesis and Characterization of 2-Aminoimidazoles --- p.50 / Chapter 3.3.3 --- Proposed Reaction Mechanism --- p.55 / Chapter 3.4 --- Summary --- p.57 / Chapter Chapter 4 --- Conclusion --- p.59 / Chapter Chapter 5 --- Experimental Section --- p.61 / References --- p.87 / Appendix / Chapter I. --- Publication Based on the Research Findings --- p.93 / Chapter II. --- Crystal Data and Summary of Data Collection and Refinement --- p.94 / Chapter III. --- X-ray crystallographic data in CIF (electronic form)

Yu Wei-jian. / Thesis submitted in: November 2000. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 70-71). / Text in English; abstracts in English and Chinese. / Yu Wei-jian. / TITLE PAGE --- p.i / THESIS COMMITTEE --- p.ii / ABSTRACT (English) --- p.iii / ABSTRACT (Chinese) --- p.iv / ACKNOWLEDGEMENTS --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF FIGURES --- p.viii / LIST OF TABLES --- p.ix / Chapter CHAPTER 1 --- INTRUDUCTION --- p.1 / Chapter Section 1.1 --- Background of the BN System --- p.1 / Chapter 1.1.1 --- Desirable Properties of c-BN --- p.1 / Chapter 1.1.2 --- Phases in the BN System --- p.2 / Chapter 1.1.3 --- Phase Diagram of BN --- p.4 / Chapter 1.1.4 --- Synthesis Techniques for c-BN Films --- p.5 / Chapter 1.1.5 --- Characterization of BN Films --- p.6 / Chapter Section 1.2 --- Background of Theory --- p.7 / Chapter Section 1.3 --- Objectives --- p.9 / Chapter 1.3.1 --- Determination of Stable State of BN --- p.9 / Chapter 1.3.2 --- Phonon-dispersion Relations of BN --- p.9 / Chapter 1.3.3 --- "Phase (p, T) Diagram" --- p.10 / Chapter 1.3.4 --- Transformation Paths in Direct Compressions --- p.10 / Chapter Section 1.4 --- Roadmap --- p.11 / Chapter CHAPTER 2 --- METHODS --- p.12 / Chapter Section 2.1 --- Density Functional Theory (DFT) for E0 Calculation --- p.12 / Chapter Section 2.2 --- Direct Force-constant Method --- p.16 / Chapter Section 2.2 --- Quasi-harmonic Approximation --- p.26 / Chapter CHAPTER 3 --- RESULTS --- p.27 / Chapter Section 3.1 --- Stable State of BN --- p.27 / Chapter Section 3.2 --- Phonon-dispersion Relations --- p.29 / Chapter Section 3.3 --- "Phase (p, T) Diagram of BN" --- p.36 / Chapter Section 3.4 --- Transformation Paths via Direct Compression --- p.44 / Chapter 3.4.1 --- Direct Compression of h-BN and r-BN --- p.46 / Chapter 3.4.2 --- Direct Compression of t-BN --- p.50 / Chapter Section 3.5 --- Energy Barriers in the Transformation of h-BN to c-BN --- p.52 / Chapter CHAPTER 4 --- DISCUSSION --- p.58 / Chapter Section 4.1 --- Transition States in the Transformation of h-BN to c-BN --- p.58 / Chapter Section 4.2 --- Phonon-dispersion Relations --- p.60 / Chapter Section 4.3 --- Phase Diagrams --- p.62 / Chapter Section 4.4 --- Future Studies --- p.63 / Chapter 4.4.1 --- Cubic BN Films Formation --- p.63 / Chapter 4.4.1.1 --- Nanoarches Nucleation --- p.64 / Chapter 4.4.1.2 --- Growth: Interfaces Between h-BN {0001} and c-BN Planes --- p.64 / Chapter 4.4.2 --- Transformation Paths of w-BN to c-BN and h-BN to r-BN --- p.65 / Chapter CHAPTER 5 --- CONCLUSION --- p.66 / APPENDIX: Mechanistic Models in c-BN Films Formation --- p.67 / REFERENCES --- p.70

Phosphorus-boron multiple-bonds are of interest because of their predicted reactivity with small molecules; their potential as reagents for the synthesis of molecules isosteric to carbon analogues which exhibit conjugation; and because they have potential as nucleation sites for the solution-phase synthesis of boron phosphide. Phosphaborenes (RP=BR') have not yet been reported due to their propensity to oligomerise to dimers or trimers, even with bulky and electronically-stabilising substituents upon phosphorus and boron. Base-stabilisation at boron allows the isolation of phosphaborenes by preventing oligomerisation, although this alters the reactivity of the phosphaborene unit. An alternative method of studying phosphaborenes free of base or acid coordination is via their thermal generation from a phosphaborene dimer and subsequent in situ reactions with suitable substrates. Chapter 1 examines the potential uses of phosphaborenes in the context of other low-valent main group molecules. The likely reactivity of phosphorus-boron multiple bonds is discussed in the context of the iminoboranes (RNBR') and the isoelectronic heavier group 14 alkyne and alkene analogues. The use of unsaturated main group fragments to build molecular clusters is considered along with the potential role that phosphorus boron multiple bonds could play in preparing boron phosphide fragments. The uses and methods of preparation of group 13/15 containing molecules exhibiting conjugation are discussed, along with the possibility that phosphaborenes would be useful reagents to prepare new P-B/C-C isosteres. Chapter 2 looks at how base-promoted trimethylsilylchloride elimination can be used to prepare base-stabilised phosphaborenes from suitable precursors (RP(SiMe₃)B(X)R' and the mechanism of these reactions. The reactivity of base-stabilised phosphaborenes with Lewis acids is also examined. Chapter 3 covers how base-promoted (L = base) trimethylsilyl halide abstraction from functionalised precursors ((Me₃Si)₃P·BBr₃) can be harnessed to prepare new functionalised phosphinoboranes ((Me₃Si)₂PB(L)Br₂) and phosphaborenes (Me₃SiP=B(L)Br). A 1-dihydro-2-dibromo functionalised phosphinoborane H₂PB(Br₂)L can be prepared from Me₃Si)₂PB(Br₂)L. A subsequent base-promoted dehydrohalogenation yields the hydro-bromo substituted phosphaborene HP=B(L)Br. Chapter 4 examines the in situ thermal generation of a phosphaborene generated from a phosphaborene dimer and its reactivity with bases and unsaturated organic molecules to prepare 1,2-phosphaboretes and 1,2-phosphaboretanes. Chapter 5 explores the diverse reactivity of the 1,2-phosphaboretes. 1,2- phosphaboretes are capable of FLP-like insertion reactions with an isonitrile and carbon monoxide. They are also ring-opened by the coordination of a Lewis acid or base to phosphorus or boron respectively to give P-B containing butadiene analogues. The reaction of the 1,2-phosphaborete with phenyl acetylene proceeds via an unusual carbon-carbon bond cleavage to generate the first example of a 1,3- phosphaborine benzene analogue, rather than the expected 1,4-phosphaborine.

Boron complexes of porphyrin analogues are rare and typically difficult to prepare. The possibility of extending this chemistry further to include corroles was intriguing and provided the main motivation for this work. The coordination chemistry of boron with corroles was explored. The aim was to see whether boron could be coordinated within the corrole N4 core and if so whether novel or similar structural types resulted, relative to the closely related porphyrin system. Boron halides and aryl halides were reacted with free base corroles in the presence of diisopropylethylamine. The methodology employed was similar to that used for boron porphyrin systems. As well as free base corrole, an N-methyl corrole and trilithiated corrole were also used as starting materials. Several boron corrole structural types were obtained. The reaction of free base corrole with boron trifluoroetherate led to the first structurally characterised corrole with boron bound within the N4 core, B2OF2(corrole). From this reagent a mono-boron species, BF2(corrole) was also obtained. With dichlorophenylborane, several boron corrole complexes were prepared including PhB2O(corrole), PhB2(corrole) and B2Ph2H(corrole). The latter species was structurally characterised and the bridging hydride is proposed to form through a reductive coupling process. Use of N-methyl corrole effectively blocked one boron binding site and subsequently mono-boron corroles BF2(N-methyl- corrole), BPh(OH)(N-methyl corrole) and BPhF(N-methyl corrole) were prepared in good yields. The reaction of lithiated corrole and dichloroplenylborane afforded B2Ph2Cl(corrole). Overall, several new boron corrole species were prepared, significantly extending the library of known boron complexes with ligands related to the porphyrin system.

Graduation date: 1997

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 201-231).

Malgrat que hi ha molta química descrita al voltant dels borans i dels carborans, la falta de mètodes sintètics fa palesa la manca de clústers substituïts en els àtoms de bor. Concretament en el cas de l'o-carborà, la substitució en els bors no és tant comú com sobre els carbonis donada la menor acidesa dels hidrògens units a ells. Per poder funcionalitzar-los generalment es duu a terme una substitució electrofílica que tant sols és efectiva sobre els àtoms de bor més llunyans dels àtoms de carboni, restant les posicions directament connectades a ambdós àtoms de carboni, B3 i B6 sense substituïr. Així doncs, l'objectiu del present treball és l'estudi de la reactivitat sobre els àtoms de bor, centrant-se en la dels àtoms B3 i B6.Per assolir l'objectiu, s'ha dissenyat un mètode simple i ràpid per a la síntesi amb alt rendiment de borats halogenats de fórmula [B6X6]2- (X = Br, I). També s'han sintetitzat i caracteritzat carborans halogenats (iodats i bromats) en la posició 3 del clúster d'o-carborà. Per a aquests clústers s'han dut a terme càlculs teòrics dels desplaçaments químics de 11B-RMN i s'ha estudiat la seva reactivitat davant reactius de Grignard obtenint derivats alquílics i arílics a la posició 3 del clúster d'o-carborà. Per a un d'aquests compostos, el 3-Iodo-1,2-dicarba-closo-dodecaborà, s'ha estudiat la reactivitat de l'enllaç B-I front a la reacció amb metalls. En el cas del magnesi s'ha desenvolupat un nou mètode de reducció de l'o-carborà. A més a més, per difracció de raigs X s'ha resolt l'estructura crista·lina del 3-Iodo-1,2-dicarba-closo-dodecaborà en la que s'ha evidenciat l'existència d'interaccions intermoleculars. Per degradació parcial dels clústers halogenats closo, s'han sintetitzat nido-carborans halogenats en la posició 3 del clúster. També s'ha sintetitzat i caracteritzat el 3,6-I2-1,2-dicarba-closo-dodecaborà. Per a aquest clúster, la reacció amb derivats de Grignard ha permès obtenir carborans substituïts en les posicions 3 i 6 amb restes alquílics i arílics i s'ha demostrat com el desplaçament químic i en alguns casos l'acidesa dels àtoms d'hidrogen units als àtoms de carboni del clúster, depèn del tipus de substituent que es troba en aquestes posicions, essent un efecte additiu.També s'han sintetitzat i caracteritzat derivats de l'o-carborà nona i deca-B-iodats. Les síntesis s'han dut a terme en globalment dues etapes. La primera es basa en la combinació de les reaccions de degradació parcial i inserció que permet obtenir el clúster iodat en posició 3 o bé 3 i 6 i la segona en un atac electrofílic amb ICl sobre el clúster mono o diiodat que porta a l'obtenció del clúster nonaiodat o decaiodat respectivament. S'ha estudiat l'acidesa dels àtoms d'hidrogen units als àtoms de carboni del derivat per-B-iodat de l'o-carborà front la desprotonació amb diferents bases i la protonació de la seva base conjugada amb diferents àcids. S'han sintetitzat i caracteritzat nido-carborans octa i nona-halogenats.També s'ha sintetitzat el carborà nonametilat en dues etapes. La primera es basa en la combinació de les reaccions de degradació parcial, inserció i acoblament creuat que permet obtenir el 3-metil-o-carborà i la segona en un atac electrofílic amb MeI sobre el clúster monosubstituït que porta a l'obtenció del clúster nonametilat. Intents de sintetitzar el clúster per-B-metilat, han portat a un carborà octametilat. Aquest fet experimental s'ha atribuït a l'efecte dels grups metil sobre els àtoms de bor del clúster que ha estat quantificat mitjançant càlculs teòrics. Així, a mesura que augmenta el nombre de grups metil, augmenta la càrrega total positiva en el clúster, disminuint la susceptibilitat a l'atac electrofílic. Finalment s'ha estudiat l'aplicació de closo-carborans halogenats en el camp del radiomarcatge. / Although the chemistry of borates and carboranes is already quite well developed, the lack of synthesis methods makes plausible the need of new boron substituted carboranes. In the case of o-carborane, boron substitution is not so common as carbon substitution due to the lower acidity of the hydrogen atoms bonded to boron atoms. Functionalization of boron atoms in o-carborane is usually achieved by electrophilic substitution. This is only effective on the boron atoms remote to carbon atoms, leaving B3 and B6, adjacent to carbon atoms, unsubstituted. For this reason, the aim of this work is the study of the reactivity on boron atoms, concretely on B3 and B6.To achieve this aim, an easy and fast method to synthesise halogenated borates [B6X6]2- (X = Br, I) in high yield has been developed. B3-halogenated (iodinated and brominated) carboranes have also been synthesised. For these clusters, theoretical 11B-NMR chemical shifts has been calculated and through cross coupling with Grignard reagents alkyl and aryl B3-substituted carboranes have been obtained. For the 3-Iodo-1,2-dicarba-closo-dodecaborane, the reactivity of the B-I bond in front of different metals has been studied. In the case of magnesium, a new o-carborane reduction method has been developed. Furthermore, through X-Ray diffraction, the existence of intermolecular interactions in the crystal structure of 3-Iodo-1,2-dicarba-closo-dodecaborane has been evidenced. Through partial deboronation of halogenated closo clusters, halogenated nido-carborane has been obtained. The synthesis of 3,6-I2-1,2-dicarba-closo-dodecaborane has also been substituted. For this cluster, the cross coupling reaction with alkyl and aryl magnesium salts led to the obtaining of B3 and B6 disubstituted carboranes. The chemical shift, and in some cases the acidity of the hydrogen atoms bonded to cluster carbon atoms, depends on the type of substituent at B3 and B6, with additive effects.Nona and deca iodinated carboranes have been synthesised and characterized. In both cases the synthesis procedure has two main steps. One step is based on the combination of partial degradation and insertion of a new vertex that allows the obtaining of the iodinated cluster at B3 or B3 and B6. The second step consists in an electrophilic attack with ICl on the nona or decaiodinated clusters respectively. The acidity of the hydrogen atoms bonded to cluster carbon atoms of the per-B-iodinated carborane has been studied through the deprotonation with different bases and the protonation of its conjugated base with different acids. Octa and nona-halogenated nido carboranes have also been synthesised and characterized.A nonamethylated carborane has also been synthesised by two steps. One step is based on the combination of the partial degradation reaction, insertion and cross coupling reaction to obtain 3-methyl-o-carborane and the second step consists in an electrophilic attack with MeI on the monosubstituted cluster to lead the nonamethylated cluster. Attempts to synthesise the per-B-methylated cluster, led an octamethylated carborane. This experimental fact has been attributed to the methyl groups effect on the boron atoms. This effect has been quantified by theoretical calculations. The higher is the number of methyl groups, the higher the total cluster positive charge, decreasing thent the electrophilic attack susceptibility. Finally, the application of halogenated closo-carboranes in radiolabelling has been studied.

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