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Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
29Si-13C spin-spin couplings over an Si-O-Csp3 link
Jan Sýkora1, Vratislav Blechta, Ludmila Soukupová
1Institute of Chemical Process Fundamentals of the ASCR, v.v.i., Rozvojová 135,16502 Prague 6, Czech Republic.
Nuclear magnetic resonance (NMR) studies reveal insights into silicon-29 to carbon-13 spin-spin couplings in trimethylsilylated alcohols. These findings enhance understanding of molecular structure and bonding in organosilicon compounds.
Area of Science:
- Organosilicon Chemistry
- Nuclear Magnetic Resonance Spectroscopy
- Computational Chemistry
Background:
- Nuclear magnetic resonance (NMR) spectroscopy is crucial for elucidating molecular structures.
- Understanding spin-spin coupling constants provides detailed information about bonding pathways.
- Trimethylsilylated alcohols represent a significant class of organosilicon compounds.
Purpose of the Study:
- To investigate and calculate silicon-29 to carbon-13 (29Si-13C) spin-spin couplings in various trimethylsilylated alcohols.
- To determine the signs and magnitudes of coupling constants across one, two, and three bonds.
- To explore the influence of molecular structure, including branching, on these NMR parameters.
Main Methods:
- Experimental measurement of NMR parameters, including chemical shifts (delta) and coupling constants (J).
- Theoretical calculations of (29)Si-(13)C spin-spin couplings and other NMR parameters.
- Analysis of a series of trimethylsilylated alcohols with varying alkyl and aryl substituents.
Main Results:
- Calculated and measured (29)Si-(13)C coupling constants over one, two, and three bonds for diverse trimethylsilylated alcohols.
- Determined the signs of coupling constants, with 2-bond ((2)J) being positive and 3-bond ((3)J) being negative.
- Established that the magnitudes of these couplings are influenced by branching at the alpha-carbon.
Conclusions:
- The signs of determined coupling constants can be reliably extended to similar compounds, supported by theoretical calculations.
- The observed sign and magnitude trends in (29)Si-(13)C couplings offer valuable structural information.
- This study provides a comprehensive NMR characterization of trimethylsilylated alcohols, aiding in their structural identification and analysis.
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