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Unformatted text preview: ated in t1 by νH only.
• FT with respect to t1 gives one 1H signal along the F1 axis with a
frequency νH.
For 13CHCl3: For more complex molecules: 1H Chemical Shift 13C Chemical Shift 13 NOTE: 1) Easy to assign C signals if 1H signals are assigned, or vice
versa. 2) Little overlap of the correlation peak.
7 4. TwoDimensional Homonuclear (H,H)Correlated NMR
Spectroscopy. H,HCOSY:
A) Pulse sequence Lets consider the case where Θx' = 90˚x' and lets consider a
homonuclear twospin AX system.
First 90˚x' pulse:
• Tilt both vectors MA and MX along y'
• Due to JAX, MA has two components MA(Xα) and MA(Xβ), and MX
has two components MX(Aα) and
MX(Aβ).
During t1:
• νA (Xα) = νA  1/2*JAX; νA (Xβ) = νA + 1/2*JAX
νX (Aα) = νX  1/2*JAX; νX (Aβ) = νX + 1/2*JAX • ϕ(MA(Xα))=2π (νA  1/2*JAX) t1; ϕ(MA(Xβ))=2π (νA + 1/2*JAX) t1
ϕ(MX(Aα))=2π (νX  1/2*JAX) t1; ϕ(MX(Aβ))=2π (νX + 1/2*JAX) t1 • At the end of t1, the vectors have components along x' and y' 8 After the second 90˚x' pulse:
• The y and y vector components are tilted along z and z, which
results in polarization transfer. The transfer depends on t1,ν, an...
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 Fall '08
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 Equilibrium

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