|
|
Activation of ferrocene ligands by sandwich complexes of Group 4 metals
Kout, Matyáš ; Štěpnička, Petr (advisor) ; Vojtíšek, Pavel (referee)
This bachelor thesis deals with synthesis, reactivity and characterization of compounds resulting from the reactions of substituted ferrocene ligands with electron- deficient complexes of group 4 transition metals in oxidation state II with the aim of finding experimental conditions for preparation of complexes containing two metal atoms in one molecule. Reactions were performed under inert atmosphere and the products were crystallized. The obtained crystals were subjected to X-ray diffraction analysis and to NMR spectroscopy in order to elucidate molecular structure of the isolated products. Along the way, instability of the prepared compounds towards air oxygen and moisture has surfaced, though it also led to a discovery of several original compounds. Among these, the molecule containing peroxide ligand bonded to zirconocene fragment is worth noting as a fine example of oxygen molecule activation with low oxidative state complexes of transition metals.
|
|
|
Development of new syntheses of condensed aromatic compounds
Kaiser, Reinhard Peter
This work is divided into two parts that are focused on the synthesis and assessment of photophysical properties of two structurally related compounds: (i) 9,9'-spirobifluorenes (SBFs) and (ii) dispiroindeno[2,1-c]fluorenes (DS-IFs). (i) In the first part, a five-step synthetic approach to SBFs was developed and as the crucial step was used an intermolecular [2+2+2] cyclotrimerization of symmetrically or unsymmetrically substituted diynols with alkynes catalyzed by Rh-complexes. Catalyst screening showed that Wilkinson's catalyst (RhCl(PPh3)3) had the highest efficiency in yielding 1,2,3,4-substituted fluorenols - the key intermediates. The fluorenols were then converted into SBFs bearing various electron-donating and -withdrawing groups, aromatic substituents, and -extended aromatic hydrocarbon moieties (PAHs). Altogether 19 different SBFs were prepared and their photophysical properties screened. The fluorescent emission maxima em were in the range of 315-389 nm with excellent quantum yields s (up to 1.00). As far as the substituent effect is concerned the presence of electron-withdrawing substituents on the SBF scaffold results in the red-shift of the emission maxima. (ii) In the second part, a similar synthetic strategy was applied for synthesis DS-IFs. In this instance was utilized again the...
|
|
|
Activation of ferrocene ligands by sandwich complexes of Group 4 metals
Kout, Matyáš ; Štěpnička, Petr (advisor) ; Vojtíšek, Pavel (referee)
This bachelor thesis deals with synthesis, reactivity and characterization of compounds resulting from the reactions of substituted ferrocene ligands with electron- deficient complexes of group 4 transition metals in oxidation state II with the aim of finding experimental conditions for preparation of complexes containing two metal atoms in one molecule. Reactions were performed under inert atmosphere and the products were crystallized. The obtained crystals were subjected to X-ray diffraction analysis and to NMR spectroscopy in order to elucidate molecular structure of the isolated products. Along the way, instability of the prepared compounds towards air oxygen and moisture has surfaced, though it also led to a discovery of several original compounds. Among these, the molecule containing peroxide ligand bonded to zirconocene fragment is worth noting as a fine example of oxygen molecule activation with low oxidative state complexes of transition metals.
|
|
|
Development of new syntheses of condensed aromatic compounds
Kaiser, Reinhard Peter
This work is divided into two parts that are focused on the synthesis and assessment of photophysical properties of two structurally related compounds: (i) 9,9'-spirobifluorenes (SBFs) and (ii) dispiroindeno[2,1-c]fluorenes (DS-IFs). (i) In the first part, a five-step synthetic approach to SBFs was developed and as the crucial step was used an intermolecular [2+2+2] cyclotrimerization of symmetrically or unsymmetrically substituted diynols with alkynes catalyzed by Rh-complexes. Catalyst screening showed that Wilkinson's catalyst (RhCl(PPh3)3) had the highest efficiency in yielding 1,2,3,4-substituted fluorenols - the key intermediates. The fluorenols were then converted into SBFs bearing various electron-donating and -withdrawing groups, aromatic substituents, and -extended aromatic hydrocarbon moieties (PAHs). Altogether 19 different SBFs were prepared and their photophysical properties screened. The fluorescent emission maxima em were in the range of 315-389 nm with excellent quantum yields s (up to 1.00). As far as the substituent effect is concerned the presence of electron-withdrawing substituents on the SBF scaffold results in the red-shift of the emission maxima. (ii) In the second part, a similar synthetic strategy was applied for synthesis DS-IFs. In this instance was utilized again the...
|
|
|
Development of new syntheses of condensed aromatic compounds
Kaiser, Reinhard Peter ; Kotora, Martin (advisor) ; Starý, Ivo (referee) ; Dvořák, Dalimil (referee)
This work is divided into two parts that are focused on the synthesis and assessment of photophysical properties of two structurally related compounds: (i) 9,9'-spirobifluorenes (SBFs) and (ii) dispiroindeno[2,1-c]fluorenes (DS-IFs). (i) In the first part, a five-step synthetic approach to SBFs was developed and as the crucial step was used an intermolecular [2+2+2] cyclotrimerization of symmetrically or unsymmetrically substituted diynols with alkynes catalyzed by Rh-complexes. Catalyst screening showed that Wilkinson's catalyst (RhCl(PPh3)3) had the highest efficiency in yielding 1,2,3,4-substituted fluorenols - the key intermediates. The fluorenols were then converted into SBFs bearing various electron-donating and -withdrawing groups, aromatic substituents, and -extended aromatic hydrocarbon moieties (PAHs). Altogether 19 different SBFs were prepared and their photophysical properties screened. The fluorescent emission maxima em were in the range of 315-389 nm with excellent quantum yields s (up to 1.00). As far as the substituent effect is concerned the presence of electron-withdrawing substituents on the SBF scaffold results in the red-shift of the emission maxima. (ii) In the second part, a similar synthetic strategy was applied for synthesis DS-IFs. In this instance was utilized again the...
|
|
|
Synthesis of 1,2-disubstituted cyclopentadienes and their application in syntheses of metallocenes
Vician, Marek ; Kotora, Martin (advisor) ; Míšek, Jiří (referee)
In this master thesis 1,2-disubstituted cyclopentadienes were prepared by method composed of three transition metal catalysed reactions. Then, the cyclopentadienes were converted into cyclopentadienyl manganese, rhenium and iron complexes. A one-pot synthesis of the cyclopentadienyl metal complexes was developed without isolation of the intermediate cyclopentadienes. The second goal of this thesis was preparation of vinyl-substituted cyclopentadienes using ring closing enyne metathesis. The last part of thesis dealt with synthesis of a chiral cyclopentadiene and preparation of the corresponding metal complexes. The important part of this work was preparation of starting materials using palladium catalysed cross-coupling reactions. Key words: cyclopentadienes, carbometallation, cross-coupling, metathesis, metallocenes.
|
guest ::
