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Ch. 15 - Structural Identification 2: Nuclear Magnetic Resonance Spectroscopy
Mullins - Organic Chemistry: A Learner Centered Approach 1st Edition
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Mullins 1st EditionCh. 15 - Structural Identification 2: Nuclear Magnetic Resonance Spectroscopy문제 40a
14장, 문제 40a

Draw the expected signal for a hydrogen with the following coupling constants.
(a) Hₐ : δ 5.34 (Jₐ꜀ = 12 , Jₐ₆ = 2)
Chemical structure with labeled hydrogens: Hₐ, Hᵦ, H꜀. Hₐ has coupling constants Jₐ꜀ = 12, Jₐ₆ = 2.

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1
Identify the type of hydrogen environment: The hydrogen Hₐ is located at δ 5.34 ppm, which suggests it is in an alkene or aromatic environment.
Understand the coupling constants: Jₐ꜀ = 12 Hz indicates a trans coupling, typical for alkenes, while Jₐ₆ = 2 Hz suggests a long-range or allylic coupling.
Determine the splitting pattern: The hydrogen Hₐ will be split into a doublet of doublets due to the two different coupling constants.
Draw the signal: Start by drawing a doublet with a splitting of 12 Hz, then split each of these peaks further into doublets with a splitting of 2 Hz.
Label the peaks: Ensure that the peaks are labeled with the correct coupling constants, showing the larger splitting (12 Hz) and the smaller splitting (2 Hz).

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주요 개념

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Chemical Shift (δ)

Chemical shift (δ) is a measure of the resonance frequency of a nucleus relative to a standard in a magnetic field. It is expressed in parts per million (ppm) and provides information about the electronic environment surrounding the nucleus. In this question, δ 5.34 indicates the position of the hydrogen signal on the NMR spectrum.
추천 영상:
11:44
1H NMR Chemical Shifts

Coupling Constant (J)

The coupling constant (J) is a parameter that quantifies the interaction between nuclear spins in NMR spectroscopy, resulting in signal splitting. It is measured in Hertz (Hz) and reflects the strength of spin-spin coupling. Jₐ꜀ = 12 Hz and Jₐ₆ = 2 Hz indicate the splitting pattern of the hydrogen signal due to interactions with neighboring nuclei.
추천 영상:
02:54
Sonogashira Coupling Reaction

Signal Multiplicity

Signal multiplicity refers to the number of peaks observed in an NMR signal due to spin-spin coupling. It is determined by the number of neighboring hydrogen atoms and their coupling constants. In this question, the hydrogen signal will be split into a pattern based on the given coupling constants, indicating the presence of adjacent hydrogen atoms.
추천 영상:
02:02
Identifying Proton Signals
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