J-HMBC / Broadband XLOC

Sequences

• ₁ = ( 2×(J^min + 0.070(J^max - J^min)))^-1
• ₂ = ( J^max + J^min)^-1
• ₃ = ( 2×(J^max - 0.070(J^max - J^min)))^-1
• _i: duration of low-pass J filter (LPJF)
• : scaling factor for apparent upscaling of ⁿJ(X,H)
• = × t₁^max
• t_A = 0.5 × ( - _i + t₁^max) -
• t_B = 0.5 × ( + t₁^max - (1 + )×t₁)
• t_C = 0.5 × ( ×t₁ + _i) +
• = gradient delay
• Gradient ratios:
  • LPJF: +7, -4, -2, -1
  • Echo: +5.0 : -3.0
  • Antiecho: -3.0 : +5.0

• ₁ = ( 2×(J^min + 0.070(J^max - J^min)))^-1
• ₂ = ( J^max + J^min)^-1
• ₃ = ( 2×(J^max - 0.070(J^max - J^min)))^-1
• _i: duration of low-pass J filter (LPJF)
• : Excitation delay
• = gradient delay
• Gradient ratios:
  • LPJF: +7, -4, -2, -1
  • Echo: +5.0 : -3.0
  • Antiecho: -3.0 : +5.0

Results

Expansion of a constant-time J-HMBC spectrum of 15 µl of ethyl trans-cinnamate in 600 µl CDCl₃ at 25° C. = 500 ms, = 22;

F₁ sections from J-HMBC spectra of 15 µl of ethyl trans-cinnamate in 600 µl CDCl₃ at 25° C. = 500 ms and = 22 which results in an apparent splitting of the doublet components by J relative to the ¹³C chemical shifts.

References

• Meissner, A. and Sorensen, O.W. Measurement of J(H,H) and long-range J(X,H) coupling constants in small molecules. Broadband XLOC and J-HMBC Magn.Reson.Chem. 39 49-52 2001

Code and procedures

For Varian and Bruker.