New Borylation Strategy for the Construction of Borylated Heterocycles and Bodipy Derivatives
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Authors
Yuan, Kang
Date
Type
thesis
Language
eng
Keyword
Boron Chemistry
Alternative Title
Abstract
This thesis mainly concerns: (1) developing new borylation strategies for heterocycles through addition of a B-E σ bond (E = H, N) across internal alkynes; (2) synthesizing BODIPY derivatives with interesting properties via “pre-functionalization” strategy; (3) preparing boron-based stimuli-responsive compounds for fluoride sensing.
The hydroboration of alkynes is known to proceed in a cis-fashion. Catalytic trans-hydroboration has been established in the past decade while catalyst-free trans-hydroboration was unknown. In the study of hydroboration reactions, an unexpected pyridine-directed trans-hydroboration of internal alkynes was disclosed and presented. This transformation could serve as a facile method to construct novel luminescent N,C-chelate organoboron compounds.
In the study of the amine directed hydroboration reaction, a facile dehydrogenative coupling between alkynyl aryl amines and 9-BBN was discovered. Based on the dehydrogenated products, a catalytic trans-aminoboration of internal alkynes was designed to give borylated indole derivatives. The reaction scope to different boranes and anilines was surveyed to generate a variety of borylated indoles.
The dehydrogenative coupling of arylamines with 9-BBN described above represents a convenient method to construct a B-N covalent bond. By switching 9-BBN to monosubstituted boranes, a family of novel azaborabenzofulvenes was obtained by exploiting sequential dehydrogenative hydroboration of alkynyl arylamines. Both the reaction scope and the properties of the products were studied.
Boron-dipyrromethene (BODIPY) and derivatives are excellent luminophores with bright emission in dilute solutions. However, they are rarely emissive in the solid state. In chapter 5, several spiro-BODIPYs with the “pre-functionalization” strategy were prepared. The spiro-structure successfully precludes the formation of π-stacking and leads to efficient solid state emissions. More interestingly, the spiro-BODIPYs formed J-aggregates in methanol-water mixed solvents.
With the same strategy, a ferrocene functionalized BODIPY featuring direct Fc-B bond was prepared. Detailed studies on the novel compound and its analogues indicate the importance of ferrocenyl substituents and the bridge on their excited-state properties of BODIPY molecules.
Trivalent organoboranes have been explored as fluoride sensors by monitoring fluorescence change, which is inconvenient in practical applications. In chapter 7, a family of boron functionalized poly-ferrocene compounds were prepared and some of these molecules can be used for colorimetric fluoride sensing.
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Attribution-NonCommercial 3.0 United States
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
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Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.