Preparation of pseudopure state in a cluster of dipolar-coupled spins   with "unresolved" spectrum
  A method of creating pseudopure spin states in large clusters of coupled spins is described. It is based on filtering multiple-quantum coherence of the highest order followed by a time-reversal period and partial saturation. Experimental demonstration is presented for a cluster of six dipolar-coupled proton spins of a benzene molecule in liquid crystalline matrix, and the details of spin dynamics are studied numerically. 
Jae-Seung Lee and A. K. Khitrin