|
|
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
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...
|
guest ::
RSS feed.