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Through-Space Shielding Effects of Metal-Complexed Phenyl Rings
William H Miles1, Michael J Robinson1, Samantha G Lessard2
1Department of Chemistry, Lafayette College , Easton, Pennsylvania 18042, United States.
The Journal of Organic Chemistry
|October 19, 2016
Summary
Metal complexation influences the through-space shielding effects of phenyl rings on naphthalene methyl groups. Complexation causes subtle structural changes and alters NMR signals, with metal effects dominating over substituent effects.
Area of Science:
- Organic Chemistry
- Organometallic Chemistry
- Spectroscopy
Background:
- Naphthalene derivatives with metal-complexed phenyl rings were synthesized.
- Through-space shielding effects are crucial in understanding molecular interactions.
Purpose of the Study:
- To investigate the through-space shielding effects of phenyl rings on naphthalene methyl groups.
- To determine how substituents and metal species influence these shielding effects.
Main Methods:
- Synthesis of naphthalene compounds.
- Proton Nuclear Magnetic Resonance (¹H NMR) spectroscopy.
- X-ray crystallography.
- Density Functional Theory (DFT) calculations.
Main Results:
- Methyl signals shifted downfield upon complexation.
- Phenyl rings moved closer to the methyl group in complexes.
- Phenyl ring bonds slightly elongated after complexation.
- Metal complexation masked substituent effects on NMR signals.
Conclusions:
- Metal complexation significantly impacts the electronic and structural environment of naphthalene derivatives.
- The nature of the complexing metal is a dominant factor in observed NMR shifts.
- Structural changes upon complexation are subtle but measurable and correlate with spectroscopic data.
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