Synthesis of Chromophore Decorated Ligands and their Self-Assembly into Supramolecular Coordination Complexes
Synthesis of Chromophore Decorated Ligands and their Self-Assembly into Supramolecular Coordination Complexes
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DissertationDate of Exam
26.03.2024Date of Publication
20.03.2025Advisor
Lützen, ArneCo-Referee
Höger, SigurdMetadata
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Abstract
This thesis is concerned with the synthesis and characterization of chromophore decorated self-assembled coordination complexes (SCC’s). The SCC’s were constructed from ditopic bispyridine ligands as organic donor building blocks and tetravalent Pd(II) ions as an inorganic acceptor building block, following the molecular library approach.
To access ligands featuring a chromophoric BODIPY moiety in the exo-position, as well as linear alkoxy chains of various lengths in the endo-position, an efficient diversity oriented synthetic strategy was developed. The yield of the BODIPY synthesis in an early synthetic step could be drastically improved from ca. 10 to 20 %, in earlier works, to a typical yield of 50 to 60 % in this work. This enabled the convenient gram scale preparation of an exo-BODIPY decorated protoligand, which could be diversified into the target ligands via Williamson ether synthesis in the final synthetic step. In a similar fashion, a final stage endo-diversification of analogous exo-anthracene decorated ligands could be realized.
Ligands with parallel coordination vectors were found to assemble into dinuclear [Pd2L4] complexes, independent of the nature of the surveyed endo-substituents, as indicated by 1H-NMR, 1H-DOSY-NMR and ESI-MS. Interestingly, the endo-functions fold into the pockets between neighboring ligands, as revealed by the crystal structure of the exo-BODIPY, endo-hexyloxy substituted derivative. With increasing endo-alkoxy chain lengths, a 1:1 1H-NMR-signal splitting for protons on the exo-BODIPY unit is noted, which was investigated via variable temperature 1H-NMR, revealing a temperature dependency of the observed splitting. To rationalize this effect, four isomeric, inter-converting [Pd2L4] structures differing in the relative orientation of the alkoxy chains within the pockets is proposed. Furthermore, bulky acetyl and para-methoxybenzyl groups in the endo-position were probed for their ability to induce 1:3 self-sorting via cavity occupation.
Ligands with 120° coordination vectors were employed to assemble [Pd12L24] molecular spheres, decorated with BODIPY and anthracene moieties in the exo-positions. By mixing ligands differing in the distance between coordination sites, a size complimentary approach for the self-sorting into a [Pd12L12L’12] complex was followed. The circular arrangement of the chromophores in this complex is reminiscent of the organization of pigments in the light harvesting antenna systems of photosynthetic organisms and represents a first step in the construction of a synthetic analogue, potentially featuring a multi step energy transfer cascade.
To access ligands featuring a chromophoric BODIPY moiety in the exo-position, as well as linear alkoxy chains of various lengths in the endo-position, an efficient diversity oriented synthetic strategy was developed. The yield of the BODIPY synthesis in an early synthetic step could be drastically improved from ca. 10 to 20 %, in earlier works, to a typical yield of 50 to 60 % in this work. This enabled the convenient gram scale preparation of an exo-BODIPY decorated protoligand, which could be diversified into the target ligands via Williamson ether synthesis in the final synthetic step. In a similar fashion, a final stage endo-diversification of analogous exo-anthracene decorated ligands could be realized.
Ligands with parallel coordination vectors were found to assemble into dinuclear [Pd2L4] complexes, independent of the nature of the surveyed endo-substituents, as indicated by 1H-NMR, 1H-DOSY-NMR and ESI-MS. Interestingly, the endo-functions fold into the pockets between neighboring ligands, as revealed by the crystal structure of the exo-BODIPY, endo-hexyloxy substituted derivative. With increasing endo-alkoxy chain lengths, a 1:1 1H-NMR-signal splitting for protons on the exo-BODIPY unit is noted, which was investigated via variable temperature 1H-NMR, revealing a temperature dependency of the observed splitting. To rationalize this effect, four isomeric, inter-converting [Pd2L4] structures differing in the relative orientation of the alkoxy chains within the pockets is proposed. Furthermore, bulky acetyl and para-methoxybenzyl groups in the endo-position were probed for their ability to induce 1:3 self-sorting via cavity occupation.
Ligands with 120° coordination vectors were employed to assemble [Pd12L24] molecular spheres, decorated with BODIPY and anthracene moieties in the exo-positions. By mixing ligands differing in the distance between coordination sites, a size complimentary approach for the self-sorting into a [Pd12L12L’12] complex was followed. The circular arrangement of the chromophores in this complex is reminiscent of the organization of pigments in the light harvesting antenna systems of photosynthetic organisms and represents a first step in the construction of a synthetic analogue, potentially featuring a multi step energy transfer cascade.
Classification (DDC)
540 ChemieHütgens, Sebastian: Synthesis of Chromophore Decorated Ligands and their Self-Assembly into Supramolecular Coordination Complexes. - Bonn, 2025. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-81549
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5-81549
@phdthesis{handle:20.500.11811/12939,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-81549,
author = {{Sebastian Hütgens}},
title = {Synthesis of Chromophore Decorated Ligands and their Self-Assembly into Supramolecular Coordination Complexes},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2025,
month = mar,
note = {This thesis is concerned with the synthesis and characterization of chromophore decorated self-assembled coordination complexes (SCC’s). The SCC’s were constructed from ditopic bispyridine ligands as organic donor building blocks and tetravalent Pd(II) ions as an inorganic acceptor building block, following the molecular library approach.
To access ligands featuring a chromophoric BODIPY moiety in the exo-position, as well as linear alkoxy chains of various lengths in the endo-position, an efficient diversity oriented synthetic strategy was developed. The yield of the BODIPY synthesis in an early synthetic step could be drastically improved from ca. 10 to 20 %, in earlier works, to a typical yield of 50 to 60 % in this work. This enabled the convenient gram scale preparation of an exo-BODIPY decorated protoligand, which could be diversified into the target ligands via Williamson ether synthesis in the final synthetic step. In a similar fashion, a final stage endo-diversification of analogous exo-anthracene decorated ligands could be realized.
Ligands with parallel coordination vectors were found to assemble into dinuclear [Pd2L4] complexes, independent of the nature of the surveyed endo-substituents, as indicated by 1H-NMR, 1H-DOSY-NMR and ESI-MS. Interestingly, the endo-functions fold into the pockets between neighboring ligands, as revealed by the crystal structure of the exo-BODIPY, endo-hexyloxy substituted derivative. With increasing endo-alkoxy chain lengths, a 1:1 1H-NMR-signal splitting for protons on the exo-BODIPY unit is noted, which was investigated via variable temperature 1H-NMR, revealing a temperature dependency of the observed splitting. To rationalize this effect, four isomeric, inter-converting [Pd2L4] structures differing in the relative orientation of the alkoxy chains within the pockets is proposed. Furthermore, bulky acetyl and para-methoxybenzyl groups in the endo-position were probed for their ability to induce 1:3 self-sorting via cavity occupation.
Ligands with 120° coordination vectors were employed to assemble [Pd12L24] molecular spheres, decorated with BODIPY and anthracene moieties in the exo-positions. By mixing ligands differing in the distance between coordination sites, a size complimentary approach for the self-sorting into a [Pd12L12L’12] complex was followed. The circular arrangement of the chromophores in this complex is reminiscent of the organization of pigments in the light harvesting antenna systems of photosynthetic organisms and represents a first step in the construction of a synthetic analogue, potentially featuring a multi step energy transfer cascade.},
url = {https://hdl.handle.net/20.500.11811/12939}
}
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5-81549,
author = {{Sebastian Hütgens}},
title = {Synthesis of Chromophore Decorated Ligands and their Self-Assembly into Supramolecular Coordination Complexes},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2025,
month = mar,
note = {This thesis is concerned with the synthesis and characterization of chromophore decorated self-assembled coordination complexes (SCC’s). The SCC’s were constructed from ditopic bispyridine ligands as organic donor building blocks and tetravalent Pd(II) ions as an inorganic acceptor building block, following the molecular library approach.
To access ligands featuring a chromophoric BODIPY moiety in the exo-position, as well as linear alkoxy chains of various lengths in the endo-position, an efficient diversity oriented synthetic strategy was developed. The yield of the BODIPY synthesis in an early synthetic step could be drastically improved from ca. 10 to 20 %, in earlier works, to a typical yield of 50 to 60 % in this work. This enabled the convenient gram scale preparation of an exo-BODIPY decorated protoligand, which could be diversified into the target ligands via Williamson ether synthesis in the final synthetic step. In a similar fashion, a final stage endo-diversification of analogous exo-anthracene decorated ligands could be realized.
Ligands with parallel coordination vectors were found to assemble into dinuclear [Pd2L4] complexes, independent of the nature of the surveyed endo-substituents, as indicated by 1H-NMR, 1H-DOSY-NMR and ESI-MS. Interestingly, the endo-functions fold into the pockets between neighboring ligands, as revealed by the crystal structure of the exo-BODIPY, endo-hexyloxy substituted derivative. With increasing endo-alkoxy chain lengths, a 1:1 1H-NMR-signal splitting for protons on the exo-BODIPY unit is noted, which was investigated via variable temperature 1H-NMR, revealing a temperature dependency of the observed splitting. To rationalize this effect, four isomeric, inter-converting [Pd2L4] structures differing in the relative orientation of the alkoxy chains within the pockets is proposed. Furthermore, bulky acetyl and para-methoxybenzyl groups in the endo-position were probed for their ability to induce 1:3 self-sorting via cavity occupation.
Ligands with 120° coordination vectors were employed to assemble [Pd12L24] molecular spheres, decorated with BODIPY and anthracene moieties in the exo-positions. By mixing ligands differing in the distance between coordination sites, a size complimentary approach for the self-sorting into a [Pd12L12L’12] complex was followed. The circular arrangement of the chromophores in this complex is reminiscent of the organization of pigments in the light harvesting antenna systems of photosynthetic organisms and represents a first step in the construction of a synthetic analogue, potentially featuring a multi step energy transfer cascade.},
url = {https://hdl.handle.net/20.500.11811/12939}
}
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