For 13chcl3 for more complex molecules 1h chemical

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

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. Two-Dimensional Homonuclear (H,H)-Correlated NMR Spectroscopy. H,H-COSY: A) Pulse sequence Lets consider the case where Θx' = 90˚x' and lets consider a homonuclear two-spin 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...
View Full Document

Ask a homework question - tutors are online