The synthesis of cobalt(I) σ-alkane complex and pincer complex catalysts for the generation of polyaminoborane on scale

This thesis at looks the synthesis of a Co(I) σ-alkane complex and the development of cobalt and rhodium catalysts for the dehydropolymerisation of amine-boranes. Chapter 1 provides a brief introduction to the organometallic chemistry of cobalt and rhodium. Chapter 2 describes the synthesis of an X-ray crystallographically characterised cobalt σalkane complex, [Co(Cy2P(CH2)4PCy2)(norbornane)][BArF4]. This complex was prepared by a solid/gas route from a norbornadiene precursor via a single-crystal to single-crystal hydrogenation. SQUID magnetometry data show this complex to be in a triplet electronic state, suggesting this is a relatively unstable σ-alkane complex. Periodic DFT and electronic structure calculations demonstrated the importance of dispersive interactions between the alkane ligand and the anion framework in stabilising weak C-H→Co σ-interactions. In Chapter 3, the simple Co(II) catalyst, Co(NH((CH2)2PiPr2)2)Cl2, was used in amine-borane dehydropolymerisation. This pre-catalyst operates at low loadings to selectively give (H2B·NMeH)n polymer on a 10 g scale. Increasing catalyst loading decreased the Mn of isolated polymer, while maintaining narrow dispersities. A Mayo analysis of the polymer formed and chain transfer agents enabled the speciation of catalysis to be probed. Chapter 4 reports on a bench stable pre-catalyst, [Rh(NH((CH2)2PiPr2)2)NBD]Cl, for the selective dehydropolymerisation of H3B·NMeH2 on 10 g scale. Detailed speciation studies showed an amine-borane adduct Rh(NH((CH2)2Pi Pr2)2)H3(H3B·NMeH2) was the on-cycle resting state. Kinetic profiles of dehydrogenation were determined from eudiometer data and the rate law found to be rate = k[Catalyst]1[H3B·NMeH2]0. Kinetic isotope effects were determined using D3B·NMeH2 and H3B·NMeD2. All these data together with computational studies enabled a catalytic cycle to be determined. Mn could be selectively decreased by doping with [(H2NMe)2BH2]Cl allowing chain control as described by a Mayo analysis. Chapter 3 and 4 have enabled the preparation of polyaminoboranes on scale with chain length control

The Gold Mountain Theater Riots: A Social History of Chinese Theater Riots in San Francisco during the 1870s and 1880s

During the 1870s and 1880s, San Francisco\u27s Chinese theaters were scenes of tumultuous riots, which this thesis has designated as The Gold Mountain Theater Riots. City petitions and ordinances restricting the performances of Chinese theaters, police raids on Chinese theaters when they did not comply with these ordinances, stampedes caused by panics, and tong and Chinese theater rivalries were all catalysts for violence in America\u27s first Chinese theaters. The Gold Mountain Theater Riots attempts to gain further knowledge of why these extra-theatrical events occurred, through the examination of Chinese audiences and the police involved in these theater riots as reported in San Francisco Newspapers during this era

Parametric down-conversion from a wave-equations approach: geometry and absolute brightness

Using the approach of coupled wave equations, we consider spontaneous parametric down-conversion (SPDC) in the narrow-band regime and its relationship to classical nonlinear processes such as sum-frequency generation. We find simple expressions in terms of mode overlap integrals for the absolute pair production rate into single spatial modes, and simple relationships between the efficiencies of the classical and quantum processes. The results, obtained with Green function techniques, are not specific to any geometry or nonlinear crystal. The theory is applied to both degenerate and non-degenerate SPDC. We also find a time-domain expression for the correlation function between filtered signal and idler fields.Comment: 10 pages, no figure

Implementation of a local principal curves algorithm for neutrino interaction reconstruction in a liquid argon volume

A local principal curve algorithm has been implemented in three dimensions for automated track and shower reconstruction of neutrino interactions in a liquid argon time projection chamber. We present details of the algorithm and characterise its performance on simulated data sets.Comment: 14 pages, 17 figures; typing correction to Eq 5, the definition of the local covariance matri