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Thesis advisor: X. Peter Zhang / Halogenated compounds are useful synthetic organic molecules. One valuable tool for synthesizing halogen containing molecules are atom transfer radical addition (ATRA) reactions which can difunctionalize olefins with a halogen moiety. Many transition complexes can catalyze these reactions but have drawbacks such as the need for harsh conditions and additives. Herein we describe the first ATRA reaction catalyzed by cobalt metalloradical catalysis (Co-MRC) which shows a broad substrate scope, moderate temperatures and uses no additives. This reaction showed excellent regioselectivity, when applicable, and low levels of enantioselectivity (up to 33% ee). / Thesis (MS) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

The temperature dependence of the reactions of halogen atoms Cl and Br with SiH4 and (CH3)3SiH have been investigated with the flash photolysis-resonance fluorescence technique. CCI4 and CH2Br2 were used as precursors to produce Cl and Br atoms, respectively. Experiments gave {k(Cl + SiH4) (295 - 472 K)} = (1.56 +0.11) x 10-1 exp[(2.0 + 0.2) kJ mol'/RT] cm3 s4, {k(Br + SiH4)(295 - 575 K)} = (9.0 + 1.5) x 10-" exp[-(17.0 + 0.6) Id mol'/RT] cm3 s', {k(Cl + (CH3)3SiH)(295 - 468 K)} = (1.24 0.35) x 104 exp[(1.3 + 0.8) Id mol4/RT] cm3 s', and {k(Br + (CH3)3SiH)(295 - 456 K)} = (7.6 + 3.3) x 1010 exp[-(28.4 + 1.3) Id mol'/RT] cm3 s'. The results were compared with values from earlier work.

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No description available.

In this work, the principal concern will be with the coupling reaction and it is anticipated that the other reactions referred to above will be considered further when products of the RX-R'Li reactions are discussed.

The purpose of this study is to examine the thermal and mechanical properties of various halogen-free laminates used in handheld electronic products and to correlate these properties to the manufacturing requirements and mechanical performance. Thermal properties determined for the laminates are the glass transition temperature, x,y,z-axis CTE, time to delamination at 260˚C and 288˚C, temperature to decomposition and interconnect stress test. SEM and EDS mapping analyses have been done on the laminates to determine the chemical composition and area fraction of the filler used in the epoxy. Three different fillers are identified from the laminates: Al(OH)3, Mg(OH)2, SiO2. Results show that the SiO2 fillers presented in the laminates reduce the z-axis CTE changes and increase the time to delamination. The x and y axis CTE is found to be lower than the z-axis CTE due to the glass fibers reinforcement in both the x and y directions. The temperature to decomposition is dependent on both the fillers and epoxy chemistry. Al(OH)3 starts to decompose above 200˚C and increases the rate of decomposition at 260˚C. Its decomposition also leads to an increase in z-axis CTE above 240˚C. Interconnect stress test results show that laminates with higher temperature to decomposition exhibit longer cycles to failure. Mechanical test results indicate that the halogenated laminates without fillers perform better than the halogen-free laminates with fillers. High fillers loading increase the flexural modulus and Vickers hardness properties of the laminates but decrease both the flexural strength and energy to fracture. Silica fillers in particular are susceptible to weaken these mechanical properties. Laminates without any fillers show plastic deformation of the epoxy matrix after fracture and result in a high energy to fracture. The adhesion of fillers to the matrix is important as the better the adhesion the higher the flexural strength is for the laminates. Results show that laminates with Al(OH)3 as the major filler have higher flexural strength than laminates with silica fillers, which also demonstrates that adhesion of the Al(OH)3 fillers are better than the silica. Laminates without any filler have higher copper peel strength than laminates with fillers.

The purpose of this study is to examine the thermal and mechanical properties of various halogen-free laminates used in handheld electronic products and to correlate these properties to the manufacturing requirements and mechanical performance. Thermal properties determined for the laminates are the glass transition temperature, x,y,z-axis CTE, time to delamination at 260˚C and 288˚C, temperature to decomposition and interconnect stress test. SEM and EDS mapping analyses have been done on the laminates to determine the chemical composition and area fraction of the filler used in the epoxy. Three different fillers are identified from the laminates: Al(OH)3, Mg(OH)2, SiO2. Results show that the SiO2 fillers presented in the laminates reduce the z-axis CTE changes and increase the time to delamination. The x and y axis CTE is found to be lower than the z-axis CTE due to the glass fibers reinforcement in both the x and y directions. The temperature to decomposition is dependent on both the fillers and epoxy chemistry. Al(OH)3 starts to decompose above 200˚C and increases the rate of decomposition at 260˚C. Its decomposition also leads to an increase in z-axis CTE above 240˚C. Interconnect stress test results show that laminates with higher temperature to decomposition exhibit longer cycles to failure. Mechanical test results indicate that the halogenated laminates without fillers perform better than the halogen-free laminates with fillers. High fillers loading increase the flexural modulus and Vickers hardness properties of the laminates but decrease both the flexural strength and energy to fracture. Silica fillers in particular are susceptible to weaken these mechanical properties. Laminates without any fillers show plastic deformation of the epoxy matrix after fracture and result in a high energy to fracture. The adhesion of fillers to the matrix is important as the better the adhesion the higher the flexural strength is for the laminates. Results show that laminates with Al(OH)3 as the major filler have higher flexural strength than laminates with silica fillers, which also demonstrates that adhesion of the Al(OH)3 fillers are better than the silica. Laminates without any filler have higher copper peel strength than laminates with fillers.

Noncovalent and reversible covalent interactions have long been exploited in catalysis and supramolecular chemistry. Examples of such noncovalent interactions include hydrogen bonding, halogen bonding and CH-π and π-π interactions. Reversible covalent interactions that have been employed towards these ends comprise the formation of imines, acetals, ketals and boronate esters. This thesis describes the investigation of various noncovalent and reversible covalent interactions, and their possible applications in catalysis and novel reaction development. Chapter 1 describes the investigation of anion receptors composed of hydrogen- and halogen- bond donor groups. Binding studies of these molecules have indicated that they are capable of interacting with an anion simultaneously through hydrogen and halogen bonding. Receptor design was found to have a profound effect on the strength of the halogen bonding interaction. Receptors containing halogen-bond donors showed selectivity for halide anions over oxyanions. In Chapter 2, potential halogen bonding catalysts were synthesized and screened in a series of reactions. Incorporating halogen-bond donors into the catalysts appeared to have no beneficial effect in terms of reactivity. Explanations for these observations are discussed along with suggestions for designing future catalysts that could exploit halogen bonding interactions. Chapter 3 discusses attempts to use hydrogen-bond donor catalysts to effect catalyst-controlled stereoselective additions to 2-nitroglycals. While stereoselective additions were observed in some cases, they were not catalyst-controlled. The results from these experiments suggested that catalysts and reactions developed for simple nitroalkenes could not be easily adapted to 2-nitroglycal substrates. A review of interactions between boron containing compounds and saccharides is presented in Chapter 4. Their applications in drug delivery systems, cellular imaging and the sensing and separation of carbohydrates are discussed, in addition to their uses as protecting and activating groups in oligosaccharide synthesis. Finally in Chapter 5, the development of a regioselective boronic acid-mediated glycosylation reaction is described. This methodology was applied in the synthesis of two key intermediates used in the synthesis of a pentasaccharide derivative isolated from the plant Spergularia ramosa.

Noncovalent and reversible covalent interactions have long been exploited in catalysis and supramolecular chemistry. Examples of such noncovalent interactions include hydrogen bonding, halogen bonding and CH-π and π-π interactions. Reversible covalent interactions that have been employed towards these ends comprise the formation of imines, acetals, ketals and boronate esters. This thesis describes the investigation of various noncovalent and reversible covalent interactions, and their possible applications in catalysis and novel reaction development. Chapter 1 describes the investigation of anion receptors composed of hydrogen- and halogen- bond donor groups. Binding studies of these molecules have indicated that they are capable of interacting with an anion simultaneously through hydrogen and halogen bonding. Receptor design was found to have a profound effect on the strength of the halogen bonding interaction. Receptors containing halogen-bond donors showed selectivity for halide anions over oxyanions. In Chapter 2, potential halogen bonding catalysts were synthesized and screened in a series of reactions. Incorporating halogen-bond donors into the catalysts appeared to have no beneficial effect in terms of reactivity. Explanations for these observations are discussed along with suggestions for designing future catalysts that could exploit halogen bonding interactions. Chapter 3 discusses attempts to use hydrogen-bond donor catalysts to effect catalyst-controlled stereoselective additions to 2-nitroglycals. While stereoselective additions were observed in some cases, they were not catalyst-controlled. The results from these experiments suggested that catalysts and reactions developed for simple nitroalkenes could not be easily adapted to 2-nitroglycal substrates. A review of interactions between boron containing compounds and saccharides is presented in Chapter 4. Their applications in drug delivery systems, cellular imaging and the sensing and separation of carbohydrates are discussed, in addition to their uses as protecting and activating groups in oligosaccharide synthesis. Finally in Chapter 5, the development of a regioselective boronic acid-mediated glycosylation reaction is described. This methodology was applied in the synthesis of two key intermediates used in the synthesis of a pentasaccharide derivative isolated from the plant Spergularia ramosa.