The S3E element

The spin-state-selective excitation (S3E) element has been proposed as a restricted excitation element in the preparation period of multidimensional NMR sequences, achieving the editing into two separate subspectra corresponding of the alpha and beta spin state of the attached nucleus ( 97JMR92-128 )(also see The S3CT element).

The basic element stands for: 


	1	2	 3	 4	 receiver(beta)	 receiver(alpha)
	----------------------------------------------------------------
	45 	0	 0	 0	 0		 0
	45	0	 90	 90	 180		 180
	45	0 	 0	 180 	 0		 180
	225 	0 	 90	 270	 180		 0
	----------------------------------------------------------------
The S3E element can be also combined with a BIRD-recovery time cluster when applied to natural abundance samples. This approach has been succesfully applied to measure coupling constants and to remove diagonal peaks in NOESY spectra ( 99JMR499-140 and 00JMR195-142 ). In addition, due to this editing, the large heteronuclear one-bond coupling constants normally exploited for separation of submultiplets in E.COSY-type experiments can be suppressed.

Some published applications are:

  • Homonuclear J(HH) coupling constants from S3E-J(HH)-NOESY experiments ( 97JMR92-128 )
  • Heteronuclear J(HX) coupling constants from S3E-J(XH)-NOESY and S3E-J(XH)-TOCSY experiments ( 97JB89 , 98JACS7989 , 99JMR237-137 )
  • Simultaneous measurement of 3J(CO-HA) and 3J(HN-HA) coupling constants from a 3D S3E-H(N)CA,CO experiment ( 98JACS3803 )
  • Included in 2D and 3D TROSY-enhanced NOESY experiments ( 99JB377 )