91 research outputs found
Stereospecific Phototransformations of Atropisomeric Chromophores
No full textPhotochemical transformations are unique strategy in synthesis that enables us to
access complex and structurally diverse organic scaffolds. However, the challenges in controlling
the excited-state to perform stereoselective reactions left this method under-utilized. This
dissertation describes a novel strategy that employs atropisomeric chromophores to perform
stereospecific phototransformations. The success of this strategy is well established in thermal
chemistry but not comprehensively investigated in photochemical transformations. This research
largely relies on rotamer control in the ground state (NEER principle) wherein the axial chirality in
the starting material was transferred to point chirality in the products upon excitation.
The chapter 1 describes the principle differences between the asymmetric thermal and
asymmetric photochemical reactions. Further, a survey of methodologies developed towards
asymmetric phototransformations and their outcomes are described. A brief introduction about
the atropisomeric systems in thermal chemistry and the preliminary investigations in
phototransformations are also provided.
In chapter 2, enantiospecific disrotatory 4?-ring closure of atropisomeric 2-pyridones
were investigated. The differential axial chirality designed (sterics and H-bonding units) displayed
distinct temperature and solvent dependency on the enantiospecificity of the reaction. Eyring plot
was computed to calculate the differential activation enthalpy and entropy for the reaction. Also,
the course of phototransformation was followed through single-crystal XRD to decipher the
preferred mode of cyclization for a given isomer of 2-pyridones. The high-pressure racemization
and photoreaction study revealed that pressure provided stable chiral axis even at elevated
temperature resulting in higher enantiomeric excess (ee) in the photoproduct.
The chapters 3-5 describe the [2+2]-photocycloaddition of atropisomeric enamide,
maleimide and imine derivatives. The design features on these molecules allowed us to perform
complementary reactions that are not observed in the literature. These modifications were
significant improvement to ?axial to point chiral? strategy that improves the versatility of the
photoreactions. For example switching of the excited state in enamides, continuous flow visibleiv
light photocatalysis of maleimides and unusual photocycloaddition of stabilized imines are notable
features.
This dissertation encompasses detailed studies on the mechanism, scope and
photophysical studies on new atropisomeric chromophores such as 2-pyridones, enamides,
maleimides and imine derivatives that provides excellent avenue to access chirally enriched
building blocks.NSF-ND EPSCoR (Doctoral Dissertation Fellowship)Department of Chemistry and Biochemistry. North Dakota State Universit
Stereospecitic Phototransformations of Axially Chiral Chromaphores
No full textVideo summarizing Ph.D. dissertation for a non-specialist audience
ChemInform Abstract: Light‐Induced Stereospecific Intramolecular [2 + 2]‐Cycloaddition of Atropisomeric 3,4‐Dihydro‐2‐pyridones.
No full textSolvent H-bonding and structural effects on the photo-reduction of Co(III) complexes in water/propan-2-ol and water/1,4-dioxane media
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K-core of co-author network (k = 10).
No full text<p>The size of the node denotes the number of papers and the thickness of interconnecting lines (edges) denotes the number of co-authored papers between the authors. Authors having 10 or more co-author links during the study period have been visualized.</p
Monsoonal Landscapes: Territorial adaptation through co-habitation in critical geographies
No full textEmergence of humans as the dominant species of the planet have come along with extreme manipulation of the earth’s systems to sustain this dominance. The Anthropocene has lasted a little over 200 years has perhaps seen the most shift from completely natural systems to requiring an additional man-made system to aid exponential growth of our species. Among earth’s systems, climate is one of the most complex factors determining energy balance of living organisms and determines energy gains and losses from organisms.India encompasses a wide range of complex territories with rich biodiversity living alongside some of the world’s highest population densities. Historically the Indians have lived and adapted to these resource abundant terrains through traditional ecological practices that aligned with the ecological systems and governed the socio-cultural practices. The current globalised world has been built upon with technological, infrastructural, sociological political and capitalistic growth has wretched devastating effects on the environment that supports us. India being a colonised country and exploited for its resources for centuries still holds traces of it in the infrastructural and production systems, in this case in the Periyar-Vaigai river basins. The region characterised by complex terrain, excessive manipulation of landforms and alteration of its resource cycles especially in water cycles by storing water in multiple dams experiences excess water flows during monsoons, causing flooding on its western slopes and proves to be the only hope for drought prone region on its eastern side. Governing such complexities lies with arbitrary administrative borders dividing the control between different states and various different departments controls the flow and management of resource which often falls short of preventing catastrophes or just management of resources.Extreme weather events in the recent past has exasperated the effects in these fragile habitats, thus the project aims to firstly mitigate the risks associated with failing monsoon, further restore the balance of the ecological system in the region. By building back resilience through co-habitation of social-ecological systems, aligned to nature using human knowledge the design aims to place value on nature rather than exploit it. The project envisions the transition from a local adaptation towards building up the system on the regional scale. It deals with primary production, anthropogenic control with respect to grey infrastructure, values and the role of ecosystems in maintain this balance. By synchronising these various systems the projects attempts at bringing back a dynamic equilibrium to this region, through methods like literature reviews, synthetic cartography and research by design.Architecture, Urbanism and Building Sciences | Transitional Territorie
Managing Leadership Development from a Gender Equity perspective: A case study approach in a typical materials company
No full textDiversity, Equity, and Inclusion are one of the latest topics getting attention among companies and universities. This reflects societal representation for gender ratios and many organizations have set goals on gender equality in creating a sustainable and innovative workplace. However, the statistics show that there is sluggish growth for women in managerial positions. This is creating a problem for promoting equity at leadership levels in every organization. Equity and equality are not the same as the former is closer to justice creating the same opportunities for all people with different abilities. Even though organizations can able to promote gender equality and achieve it with a better ratio, there is a struggle to increase women's representation at different leadership levels. The global scenario also shows that the representation of women on board and C-suite (Chief executive level like CEO, CFO, etc) is very low demanding gender equity at leadership levels. Thereby, a case study is performed in Celanese, a materials company that has better gender equality across the organization.This research is executed as an embedded single case study in both the global and Dutch context to understand this scenario and their gender representation at the management level. This is, in particular, to relate gender equality ratio progress and effectiveness for development programs to promote more women leaders supporting equitable workplace. The embedded case study is performed through ethnography research in terms of observations, qualitative interviews, and focused group discussions inside the organization. This approach helps to understand the existing scenario for women's representation and leadership development opportunities in a typical materials company. This is extended for industrial benchmarks at the global level as a comparison of gender equality ratios against their competitors. The leadership interviews with both genders focusing on women leaders are done and the outputs showed the driving factors, challenges, and future requirements to create equity-focused leadership. Further analysis is done to extract the key elements impacting gender equity for leadership development programs.Whereas, focused group discussions are aimed at involving employees at different levels and employees who are closely involved in leadership programs. So, focused group discussion is done with the Young professional group that comprises employees at different levels and Human Resources team who drives leadership programs. These discussions acted as data triangulation for qualitative interviews and provided more insights into leadership development programs from different perspectives. As a result, the existing gaps and challenges for the leadership development of women employees in an organization are studied. Facts derived from the organizational level and qualitative results provided enough reasons for ineffective development programs in supporting equity at leadership levels. This is evident that leadership levels demanded more women employees and necessary driving factors to motivate them. This also emphasized how HR policies and role model representation can contribute better in driving more female employees into leadership levels.However, the missing factor is equitable actions in leadership development programs to create an inclusive environment. Thereby, a leadership development cycle is developed to strengthen various processes making the leadership program as equity-focused and motivating female employees for leadership positions. However, the recommendations are derived using the embedded single case study and explained briefly about a roadmap showing the next future phases for equity at leadership levels and their decision-making impact on innovation. Finally, a leadership development framework is developed showing the possible methods and processes for driving more female employees from the organizational level to the leadership level. This leadership framework shows how women leaders need effective equity-focused development programs using equitable actions considering both social and professional barriers. Using this framework, the practical implications are summarized for promoting women leaders at leadership levels through equity-focused leadership development programs.Management of Technology (MoT
Practices towards prevention of food borne diseases among females in rural area of Trichy, India
No full textBackground: Food borne diseases are of great importance since it leads to multiple health problems resulting in illness, malnutrition, mortality and economic loss. These diseases share a significant proportion in the occurrence of communicable diseases. Objectives was to study the knowledge about food borne diseases and food safety among women residing in rural area.Methods: This was a cross sectional study involving 150 adult females who were residing in rural field practice areas of a tertiary care teaching hospital. Practices of safe food handling were assessed using an interviewer administered questionnaire. Informed consent was obtained, and confidentiality was maintained. Appropriate descriptive statistical analysis was done.Results: Out of 150 females, 147 (98%) were aware of the importance of washing hands before cooking. Sixty four (42.7%) females had a habit of washing the vegetables with water twice before cooking. 102(68%) females consumed stored food after reheating, 48(32%)females consumed without heating. Though 70% were aware of food adulteration, none of the participants have lodged compliant against adulteration.Conclusions: Through our study we found that most of the females practiced proper hand washing before cooking and proper storage of the leftover food. The proportion of females who followed adequate cleaning of non-vegetarian food items and vegetables were found to be inadequate. </jats:p
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