Multiplicity edited H2BC

Heteronuclear 2-bond correlations: A two-dimensional NMR pulse sequence for long-range correlation of 1H and 13C nuclei. Multiplicity edited: CH, CH3-correlations are separated from CH2-correlations.

Sequences

a) Standard sequence


b) Up-down sequence

Multiplicity edited H2BC with a 3rd order low-pass J filter for correlating 1H and 13C nuclei via 1JCH and 1H-1H couplings.

The sum and differences of two data sets from the two sequences, standard (a) and up-down (b), (prefarably acquired in an interleaved mode) are calculated to form odd and even datasets.

Filled and open bars refer to pi /2 and pi pulses, respectively, while the dashed boxes represent 13C decoupling.

  • tau 1 = ½ [1Jmin + 0.07(1Jmax - 1Jmin)]-1
  • tau = tau 2 = [1Jmax + 1Jmin]-1
  • tau 3 = ½ [1Jmax - 0.07(1Jmax - 1Jmin)]-1
T denotes the constant-time delay. The gradient strength G1 is G and -G for echo and antiecho selection, respectively. epsilon = 0.5 × (t( pi H) + initial value of t1/2).

The recommended phase cycle is

  • phi 1 = {x, -x, -x, x},
  • phi 2 = {x, x, 4(-x), x, x},
  • phi 3 = {4(x), 4(y), 4(-x), 4(-y)},
  • phi 4 = {16(x), 16(-x)},
  • Receiver phase {x, -x}.

Animation

Have a look at a animation showing the evolution of the t1 delay.

Results

Edited H2BC spectra H2BC-spectra of prednisolone in DMSO-d6 at 600 MHz. a) Normal H2BC-spectrum (standard sequence). b) Multiplicity edited H2BC-spectra (interleaved standard + up-down sequence added [blue, CH and CH3] and subtracted [red, CH2]). Edited H2BC spectra Expansions of NMR-spectra of prednisolone in DMSO-d6 at 600 MHz. a) Normal H2BC-spectrum (standard sequence). b) Multiplicity edited H2BC-spectra, sum of standard + up-down experiments = CH and CH3 subspectrum. c) Multiplicity edited H2BC-spectra, difference of standard + up-down experiments = CH2 subspectrum. d) HSQC. Prednisolone Prednisolone

Poster

Download the poster presented at the 27th Danish NMR discussion meeting 2006.

References

  1. Nils T. Nyberg, Jens Ø. Duus, Ole W. Sørensen Heteronuclear 2-Bond Correlation: Suppressing Heteronuclear Three-Bond or Higher NMR Correlations while Enhancing Two-Bond Correlations Even for Vanishing 2JCH J. Am. Chem. Soc. 127 6154-6155 2005
  2. Nils T. Nyberg, Jens Ø. Duus, Ole W. Sørensen Editing of H2BC NMR spectra Magnetic Resonance in Chemistry 43 971-974 2005
  3. Bent O. Petersen, Evguenii Vinogradov, William Kay, Peter Würtz, Nils T. Nyberg, Jens Ø Duus, and Ole W. Sørensen H2BC: A new technique for NMR analysis of complex carbohydrates Carbohydrate Research 341 550-556 2006

Code and procedures

For Varian and Bruker.

 
Document: Edited H2BC (index.shtml)
Last modified: 2006-03-17