Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation
The synthesis of base-stabilized germanium(I) dimers and a silagermyne were reported. In addition, the application of the base-stabilized germanium(I) dimers toward catalytic C-C bond formation of α,β-unsaturated carbonyl compounds was described. In Chapter 1, a brief introduction of low-valent heav...
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| Format: | Thesis-Master by Research |
| Language: | English |
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Nanyang Technological University
2020
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| Online Access: | https://hdl.handle.net/10356/137619 |
| _version_ | 1824456632557371392 |
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| author | Ong, Melissa Xin Yi |
| author2 | So Cheuk Wai |
| author_facet | So Cheuk Wai Ong, Melissa Xin Yi |
| author_sort | Ong, Melissa Xin Yi |
| collection | NTU |
| description | The synthesis of base-stabilized germanium(I) dimers and a silagermyne were reported. In addition, the application of the base-stabilized germanium(I) dimers toward catalytic C-C bond formation of α,β-unsaturated carbonyl compounds was described. In Chapter 1, a brief introduction of low-valent heavier group 14 element carbene analogues and multiple bonded heavier group 14 element compounds was described. The small energy difference between the HOMO and LUMO facilitates their capability of transition-metal like reactivity in small molecules activation. In Chapter 2, the synthesis of base-stabilized germanium(I) dimers and their application toward C-C bond formation of α,β-unsaturated carbonyl compounds was reported. First, treatment of the amidinate-stabilized chlorogermylene and the 2-imino-5,6-methylenedioxylphenyl chlorogermylene with potassium graphite (KC8) afforded the amidinato germanium(I) dimer [RGeGeR] and the 2-imino-5,6-methylenedioxylphenyl germanium(I) dimer [LGeGeL] respectively. With the base-stabilized germanium(I) dimers in hand, they were used to investigate C-C bond formation reactions through the polymerization of various α,β-unsaturated carbonyl compounds to form corresponding polymers with low molecular weight and low dispersity. The successful polymerization led us to investigate and propose the mechanism of polymerization in a traditional initiation-propagation-termination manner. In chapter 3, we showed the synthesis of the base-stabilized unsymmetric silagermyne [LGeSiR]. The in-situ generation of LGeK was when the 2-imino-5,6-methylenedioxylphenyl chlorogermylene was treated with excess potassium graphite. The silagermyne was afforded from the reaction of LGeK with the amidinato chlorosilylene [RSiCl]. We then investigated the reactivity of LGeSiR with various Lewis acids, chalcogens and transition metal carbonyls, of which the successful isolation of the [LGe-Te-Si(Te)R] complex was reported by X-ray crystallography. Additionally, we attempted to mimic a push-pull NHC-disilyne-ZnCl2 with LGeSiR but instead of forming the push-pull complex, we formed a [LH]-GeCl2 dimer isolable by X-ray crystallography. |
| first_indexed | 2025-02-19T03:57:11Z |
| format | Thesis-Master by Research |
| id | ntu-10356/137619 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2025-02-19T03:57:11Z |
| publishDate | 2020 |
| publisher | Nanyang Technological University |
| record_format | dspace |
| spelling | ntu-10356/1376192023-03-01T00:02:07Z Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation Ong, Melissa Xin Yi So Cheuk Wai School of Physical and Mathematical Sciences cwso@ntu.edu.sg Science::Chemistry The synthesis of base-stabilized germanium(I) dimers and a silagermyne were reported. In addition, the application of the base-stabilized germanium(I) dimers toward catalytic C-C bond formation of α,β-unsaturated carbonyl compounds was described. In Chapter 1, a brief introduction of low-valent heavier group 14 element carbene analogues and multiple bonded heavier group 14 element compounds was described. The small energy difference between the HOMO and LUMO facilitates their capability of transition-metal like reactivity in small molecules activation. In Chapter 2, the synthesis of base-stabilized germanium(I) dimers and their application toward C-C bond formation of α,β-unsaturated carbonyl compounds was reported. First, treatment of the amidinate-stabilized chlorogermylene and the 2-imino-5,6-methylenedioxylphenyl chlorogermylene with potassium graphite (KC8) afforded the amidinato germanium(I) dimer [RGeGeR] and the 2-imino-5,6-methylenedioxylphenyl germanium(I) dimer [LGeGeL] respectively. With the base-stabilized germanium(I) dimers in hand, they were used to investigate C-C bond formation reactions through the polymerization of various α,β-unsaturated carbonyl compounds to form corresponding polymers with low molecular weight and low dispersity. The successful polymerization led us to investigate and propose the mechanism of polymerization in a traditional initiation-propagation-termination manner. In chapter 3, we showed the synthesis of the base-stabilized unsymmetric silagermyne [LGeSiR]. The in-situ generation of LGeK was when the 2-imino-5,6-methylenedioxylphenyl chlorogermylene was treated with excess potassium graphite. The silagermyne was afforded from the reaction of LGeK with the amidinato chlorosilylene [RSiCl]. We then investigated the reactivity of LGeSiR with various Lewis acids, chalcogens and transition metal carbonyls, of which the successful isolation of the [LGe-Te-Si(Te)R] complex was reported by X-ray crystallography. Additionally, we attempted to mimic a push-pull NHC-disilyne-ZnCl2 with LGeSiR but instead of forming the push-pull complex, we formed a [LH]-GeCl2 dimer isolable by X-ray crystallography. Master of Science 2020-04-06T08:40:56Z 2020-04-06T08:40:56Z 2020 Thesis-Master by Research Ong, M. X. Y. (2020). Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation. Master's thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/137619 10.32657/10356/137619 en This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University |
| spellingShingle | Science::Chemistry Ong, Melissa Xin Yi Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation |
| title | Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation |
| title_full | Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation |
| title_fullStr | Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation |
| title_full_unstemmed | Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation |
| title_short | Advances in the chemistry of base-stabilized germanium(I) compounds towards C-C bond formation |
| title_sort | advances in the chemistry of base stabilized germanium i compounds towards c c bond formation |
| topic | Science::Chemistry |
| url | https://hdl.handle.net/10356/137619 |
| work_keys_str_mv | AT ongmelissaxinyi advancesinthechemistryofbasestabilizedgermaniumicompoundstowardsccbondformation |