Multiple Quantum Narrowing

13C-1H multiple-quantum coherences (MQC) are minimally affected by the one-bond 13C-1H dipolar interactions. Thus, the relaxation rate of a 13C-1H MQC for a methine spin system is slower than that of a 1H and 13C single-quantum coherence (SQC). Fot this reason, several works have been reported showing the much better sensitivity of the HMQC pulse train with respec to the analog HSQC pulse sequence when applied to 13C, as predicted theoretically.

Applications:

  • ge-2D 1H-13C CT-HMQC experiment ( 95JB335 , 99JB133-14 , 97JACS7361 )
  • ge-3D 1H-13C NOESY-HMQC experiment ( 99JB133-14 )
  • ge-3D 1H-13C ROESY-HMQC experiment ( 95JB335 )
  • ge-3D doubly-sensitivity enhanced 1H-13C TOCSY-HMQC experiment ( 99JB133-14 )
  • ge-3D HACAHB-COSY experiment to measure J(HAHB) coupling constants ( 95JACS5312 )
  • ge-3D HA(CA)(CO)NH( 97JACS9274 ), (HA)CA(CO)NH ( 97JB105 ) and (HA)CANH ( 97JB105 and 99JB169 ) experiments
  • ge-3D HCN experiment for 13C-labeled RNA ( 97JACS7361 ).
  • HMQC version of the HCACO experiment ( 92JB103 ).