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Catalytic and photochemical cycloadditions of alkynes
Fadeev, Aleksandr ; Kotora, Martin (advisor) ; Pour, Milan (referee) ; Parkan, Kamil (referee)
Novel approaches to utilizing alkynes in transition metal-catalyzed [2+2+2] cycloadditions and photochemical [2+2] cycloadditions were investigated with respect to the potential applications of these transformations. First, a chemo- and regioselective fully intermolecular cocyclotrimerization of internal alkynes with a commercially available ethynyl boronate was developed using Ru-catalysis and its mechanism was examined using DFT calculations. The established method allows for a straightforward preparation of various 1,4-diborylated benzenes, which can serve as multifunctional building blocks in organic synthesis. In particular, the products can be used in cross-coupling, carbonylation and oxidation reactions to access a broad variety of contiguously substituted arenes, such as natural products mirandamycin and violaceoid C. Second, a comparative study of catalytic and uncatalyzed photocycloadditions between alkynes and quinones was undertaken. Contrary to the recent reports, irradiation with visible light alone is sufficient to obtain not only the [2+2] cycloaddition products, but also several products of cascade transformations. Thus, depending on the structure of the quinone used, either carbo- or heterocycloaddition pathway is mainly realized, giving rise either to annulated cyclobutenes or...
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Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva ; Sedláček, Jan (advisor) ; Merna, Jan (referee) ; Červený, Libor (referee)
4 ABSTRACT The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated...
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Synthesis of aromatic compounds possessing the fluorene unit
Caivano, Ilaria ; Kotora, Martin (advisor) ; Starý, Ivo (referee) ; Tobrman, Tomáš (referee)
Thermal cyclotrimerization was first discovered in 1866 by Bertholet, then, in 1948, Reppe and Schweckendiek reported the first transition metal catalyzed [2+2+2] cyclotrimerization of alkynes using Ni complexes. In the following 70 years of research, transition metal catalyzed [2+2+2] cyclotrimerization have become a powerful method for the synthesis of variously decorated aromatic rings and new catalytic systems as well as reaction conditions have been successfully applied. Herein, I would like to show the use of this reaction for the synthesis of the important class of fluorene-based compounds. In particular, a regioselective cyclotrimerization of 2,4-disubstituted fluorenols was achieved by Ru-catalyzed partially intermolecular [2+2+2] cyclotrimerization of diynes with terminal alkynes. Rh-based complex proved to be a straightforward transition metal catalyst for the construction of selectively fluorinated [5] and [6]helical dispiroindenofluorenes using intramolecular [2+2+2] cycloaddition of triynediols as the key synthetic step. Moreover, Ni complexes demonstrated to be a valid choice for the selective synthesis of unsymmetrical [7]helical indenofluorenones, while other catalytic systems based on Rh, Ru, Pd and Co gave mixture of the desired cyclotrimerization compound together with the...
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Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva
The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated that...
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Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva ; Sedláček, Jan (advisor) ; Merna, Jan (referee) ; Červený, Libor (referee)
4 ABSTRACT The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated...
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Polycyclotrimerization of alkynes with internal ethynyl groups
Sokol, Jiří ; Sedláček, Jan (advisor) ; Balcar, Hynek (referee)
The diynes of both aliphatic and aromatic types comprising either (i) two internal ethynyl groups or (ii) one internal and one terminal ethynyl group in the molecule were revealed as appropriate monomers for the Co2(CO)8 catalyzed polycyclotrimerization yielding high-molecular-weight products. The polycyclotrimerization of aliphatic diynes with a short (CH2)2 link between ethynyl groups and the polycyclotrimerization of aromatic diynes provided polycyclotrimer networks with tri-, tetra-, penta- and hexasubstituted benzene segments. The polycyclotrimers of aliphatic diynes did not exhibit microporous texture. On the other side, the polycyclotrimers of aromatic monomers were mostly microporous with specific surface area up to SBET = 499 m2 /g. The nitrogen desorption isotherms on microporous polycyclotrimers exhibited a significant unclosed hysteresis. This indicated that the penetration of nitrogen into polymers was accompanied by formation of temporary pores or opening permanent pores of worse accessibility.
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Conjugated porous polymers derived from diethynylarenes by chain-growth polymerization and polycyclotrimerization
Slováková, Eva
The synthesis has been described yielding a new type of rigid conjugated polymer networks which possess a high content of permanent micropores and macropores and exhibit high surface areas up to 1469 m2/g. The networks have been prepared via chain-growth coordination polymerization catalysed with insertion catalysts based on Rh complexes. This polymerization has been newly applied to bifunctional acetylenic monomers of diethynylarene type (1,4-diethynylbenzene, 1,3-diethynylbenzene and 4,4'-diethynylbiphenyl). The covalent structure of the networks consists of the polyacetylene main chains densely connected by arylene struts. The W and Mo metathesis catalysts have been revealed as inefficient for the synthesis of these networks. The increase in the polymerization temperature and time has been shown to affect positively the content and the diameter (up to 22 nm) of the mesopores in the networks. A mechanism has been proposed that explains the mesopores formation as a result of mutual knitting of small particles of the microporous polymer. The application of emulsion polymerization technique allowed to prepare texturally hierarchical polyacetylene networks possessing interconnected open macropores (diameter up to 4,8 μm) the walls of which exhibited micro/mesoporous texture. It was demonstrated that...
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