Synthesis, Properties, and Solid-State Structures of a Series of 6,13-Dicyanoheteropentacene Analogues: Towards New Liquid Crystalline Materials

The focus of this thesis is the synthesis of novel heterocyclic pentacene analogs and the investigation of their self-organization for the development of new materials for organic electronics. The thesis consists of two interrelated projects: the first being development of an improved synthesis of a series of liquid crystalline dicyanotetraoxapentacenes (DCTOPs) while the second entails the exploratory synthesis of several novel dicyanoheteropentacene analogues and a preliminary investigation of their photophysical properties and solid-state structures. Both of these projects centre around the use of nucleophilic aromatic substitution reactions on tetrafluoroterephthalonitrile. Soluble, tetrakis(bis(alkoxy)phenyl)-substituted DCTOPs were originally synthesised via a short synthesis complicated by a tedious purification required in the last step. Despite this, derivatives bearing long alkyl chains were prepared which displayed liquid crystalline properties in addition to aggregation-induced emission. Building upon this success, but with the goal of achieving DCTOPs in an efficient synthetic manner for this thesis, changes were made which eliminated the troublesome fourfold Suzuki coupling by changing the order of reactions, which in turn required a protection-deprotection sequence. Purification in the new synthesis was greatly simplified and the target tetraaryl-DCTOPs were accessed in good overall yields and purities. The synthesis and solid state structures of these DCTOPs are discussed in Chapter 2. Building on the methods developed in Chapter 2, several novel pentacene analogues containing combinations of nitrogen, oxygen, and sulfur atoms installed within the pentacene core were also synthesised. These compounds were prepared in good yields, and preliminary photophysical studies show that all the compounds displayed luminescence in solution and the solid state. It was also shown that replacement of O with N leads to a red shift in absorption and emission spectra. The X-ray crystal structures show that several of these compounds exhibit π−stacking in the solid state, which is an important design element for applications in organic electronics. The synthesis, photophysical properties, and solid-state organization of these novel 6,13-dicyanoheteropentacene analogues are discussed in Chapter 3

Copper(II)- and gold(III)-mediated cyclization of a thiourea to a substituted 2-aminobenzothiazole

Benzothiazole derivatives are a class of privileged molecules due to their biological activity and pharmaceutical applications. One route to these molecules is via intramolecular cyclization of thioureas to form substituted 2-aminobenzothiazoles, but this often requires harsh conditions or employs expensive metal catalysts. Herein, the copper(II)- and gold(III)-mediated cyclizations of thioureas to substituted 2-aminobenzothiazoles are reported. The single-crystal X-ray structures of the thiourea N-(3-methoxyphenyl)-N\u27- (pyridin-2-yl)thiourea, C13H13N3OS, and the intermediate metal complexes aquabis[5-methoxy-N-(pyridin-2-yl-κN)-1,3-benzothiazol-2-amine-κN3]copper(II) dinitrate, [Cu(C13H11N3OS)2(H2O)](NO3)2, and bis{2-[(5-methoxy-1,3-benzothiazol- 2-yl)amino]pyridin-1-ium} dichloridogold(I) chloride monohydrate, (C13H12N3OS)2[AuCl2]Cl⋅H2O, are reported. The copper complex exhibits a distorted trigonal–bipyramidal geometry, with direct metal-to-benzothiazoleligand coordination, while the gold complex is a salt containing the protonated uncoordinated benzothiazole, and offers evidence that metal reduction (in this case, AuIII to AuI) is required for the cyclization to proceed. As such, this study provides further mechanistic insight into the role of the metal cations in these transformations

Comment from the Editor of IPMR Symposium Issue

The articles in this issue of IPMR are intended to be of interest to both academics and practitioners who are either involved in or are students of business process transformation in government to enhance their understanding of the inherent challenges faced in such change. The focus of this symposium edition is on Business Process Transformation in the U.S. Federal Government and the Department of Defense (DOD). The articles provide valuable information regarding past practices and policies, important recent transformational initiatives and real-world accounts of outcomes and organizational challenges as a result of these initiatives

Transformation of National Defense Business Management: Current Initiatives and Future Challenges

The major transformational challenge facing DOD in the period 2005-2008 is how to continue to re-capitalize and modernize the fighting forces while also pushing the pace of business transformation to increase efficiency. This must be accomplished while continuing to pay the high price of waging the war on terrorism. In essence, what DOD must fund and support in the short-term must be traded-off against longer-term investments to improve efficiency and force readiness

Non-commutative geometry and the standard model vacuum

The space of Dirac operators for the Connes-Chamseddine spectral action for the standard model of particle physics coupled to gravity is studied. The model is extended by including right-handed neutrino states, and the S0-reality axiom is not assumed. The possibility of allowing more general fluctuations than the inner fluctuations of the vacuum is proposed. The maximal case of all possible fluctuations is studied by considering the equations of motion for the vacuum. Whilst there are interesting non-trivial vacua with Majorana-like mass terms for the leptons, the conclusion is that the equations are too restrictive to allow solutions with the standard model mass matrix.Comment: 21 pages. v2: some comments improve

Consilient knowledge in fisheries: a case study of three species of wolffish (Anarhichadidae) listed under the Canadian Species at Risk Act

Three species of wolffish have been listed under Canada’s Species at Risk Act with consequences for commercial fisheries. Because harvester based local ecological knowledge (LEK) and science knowledge differ in goals, spatial and temporal scale, and mode of generalization, the current system struggles with including LEK along with traditional assessments in species at risk (SARA) processes. The differences in LEK and science led us to consider the concept of consilience in the sense of strengthened inductive knowledge via convergence or concordance of evidence from disparate sources. We used three criteria when considering consilience: a general concurrence of data, presence of unexplained inconsistencies, and a degree of complementarity between two disparate sources. Using wolffish in the northern Gulf of St. Lawrence we examined the feasibility of applying these criteria to two disparate sources of information: scientific stock assessments and data from structured fish harvester local ecological knowledge (LEK) interviews. We found that for wolffish there was consistency in observed trends and locations of high wolffish catch rates from both harvester LEK interviews and fishery-independent survey data. There was inconsistency between observed variability in catch sizes in harvester interviews and stock assessment maps. The science and LEK evidence were complementary in that observations took place at different spatial and temporal scales. They were complementary in that LEK was inshore, compared to science data from offshore. The explicit criteria we developed permit use of fishers’ knowledge that, in the past, has often been discounted to zero, often thereby reducing trust by harvesters in the results of species at risk assessments. The concept of consilience shifts the focus from controversy to dialogue in the use of evidence and, so, is important in rebuilding marine fishing communities

Predicting posttraumatic stress disorder after childbirth

Objective: around 50% of women report symptoms that indicate some aspect of their childbirth experience was 'traumatic', and at least 3.1% meet diagnosis for PTSD six months post partum. Here we aimed to conduct a prospective longitudinal study and examine predictors of birth-related trauma - predictors that included a range of pre-event factors - as a first step in the creation of a screening questionnaire. Method: of the 933 women who completed an assessment in their third trimester, 866 were followed-up at four to six week post partum. Two canonical discriminant function analyses were conducted to ascertain factors associated with experiencing birth as traumatic and, of the women who found the birth traumatic, which factors were associated with those who developed PTSD. Findings: a mix of 16 pre-birth predictor variables and event-specific predictor variables distinguished women who reported symptoms consistent with trauma from those who did not. Fourteen predictor variables distinguished women who went on to develop PTSD from those who did not. Conclusions: anxiety sensitivity to possible birthing problems, breached birthing expectations, and severity of any actual birth problem, predicted those who found the birth traumatic. Prior trauma was the single most important predictive factor of PTSD. Evaluating the utility of brief, cost-effective, and accurate screening for women at risk of developing birth-related PTSD is suggested