Aminoborane σ Complexes: Significance of Hydride Co-ligands in Dynamic Processes and Dehydrogenative Borylene Formation

Systems of the type [(<i>p</i>-cym)­Ru­(PR₃)­(H)­(H₂BN^<i>i</i>Pr₂)]⁺ (R = Cy, Ph) can be synthesized from (<i>p</i>-cym)­Ru­(PR₃)­Cl₂ and H₂BN^<i>i</i>Pr₂/Na­[BAr^<i>f</i>₄] and are best formulated as (hydrido)ruthenium κ¹-aminoborane complexes. VT-NMR measurements have been used to probe the σ-bond metathesis process leading to Ru–H/H–B exchange, yielding an activation barrier of Δ<i>G</i>^⧧ = 7.5 kcal mol^–1 at 161 K. Moreover, in contrast to the case for related non-hydride-containing systems, reactivity toward alkenes constitutes a viable route to a metal borylene complex via sacrificial hydrogenation

Aminoborane σ Complexes: Significance of Hydride Co-ligands in Dynamic Processes and Dehydrogenative Borylene Formation

Systems of the type [(<i>p</i>-cym)­Ru­(PR₃)­(H)­(H₂BN^<i>i</i>Pr₂)]⁺ (R = Cy, Ph) can be synthesized from (<i>p</i>-cym)­Ru­(PR₃)­Cl₂ and H₂BN^<i>i</i>Pr₂/Na­[BAr^<i>f</i>₄] and are best formulated as (hydrido)ruthenium κ¹-aminoborane complexes. VT-NMR measurements have been used to probe the σ-bond metathesis process leading to Ru–H/H–B exchange, yielding an activation barrier of Δ<i>G</i>^⧧ = 7.5 kcal mol^–1 at 161 K. Moreover, in contrast to the case for related non-hydride-containing systems, reactivity toward alkenes constitutes a viable route to a metal borylene complex via sacrificial hydrogenation

Evaluation of the Asthma Friendly Schools program

This thesis examined what makes schools want to embrace the Asthma Friendly Schools program. It also investigated the limitations and barriers of the Asthma Friendly Schools program and explored it\u27s uptake by schools and the implications of the findings for the redesign of the program

Isolation of [Ru(IPr)₂(CO)H]⁺ (IPr = 1,3-Bis(2,6-diisopropylphenyl)imidazol-2-ylidene) and Reactivity toward E–H (E = H, B) Bonds

Halide abstraction from the ruthenium N-heterocyclic carbene complex Ru­(IPr)₂(CO)­HCl (IPr = 1,3-bis­(2,6-diisopropylphenyl)­imidazol-2-ylidene) with NaBAr₄^F (BAr₄^F = B­{C₆H₃(3,5-CF₃)₂}₄) gave the salt [Ru­(IPr)₂(CO)­H]­BAr₄^F (<b>2</b>), which was shown through a combined X-ray/neutron structure refinement and quantum theory of atoms in molecules (QTAIM) study to contain a bifurcated Ru···η³-H₂C ξ-agostic interaction involving one ⁱPr substituent of the IPr ligand. This system complements the previously reported [Ru­(IMes)₂(CO)­H]⁺ cation (IMes =1,3-bis­(2,4,6-trimethylphenyl)­imidazol-2-ylidene), where a non-agostic form is favored. Treatment of <b>2</b> with CO, H₂, and the amine–boranes H₃B·NR₂H (R = Me, H) gave [Ru­(IPr)₂(CO)₃H]­BAr₄^F (<b>3</b>), [Ru­(IPr)₂(CO)­(η²-H₂)­H]­BAr₄^F (<b>4</b>), and [Ru­(IPr)₂(CO)­(κ²-H₂BH·NR₂H)­H]­BAr₄^F (R = Me, <b>5</b>; R = H, <b>6</b>), respectively. Heating <b>5</b> in the presence of Me₃SiCHCH₂ led to alkene hydroboration and formation of the C–H activated product [Ru­(IPr)­(IPr)′(CO)]­BAr₄^F (<b>7</b>). X-ray characterization of <b>3</b> and <b>5</b>–<b>7</b> was complemented by DFT calculations, and the mechanism of H₂/H exchange in <b>4</b> was also elucidated. Treatment of <b>2</b> with HBcat resulted in Ru–H abstraction to form the boryl complex [Ru­(IPr)₂(CO)­(Bcat)] BAr₄^F (<b>8</b>), which proved to be competent in the catalytic hydroboration of 1-hexene. In <b>8</b>, a combined X-ray/neutron structure refinement and QTAIM analysis suggested the presence of a single Ru···η²-HC ξ-agostic interaction