A study of long range dipolar coupling constants in 4′-pentyloxy-4-biphenylcarbonitrile (5OCB)

It was shown previously that long range H-2-C-13 dipolar coupling constants in liquid crystals could be obtained from the proton-decoupled C-13 NMR spectrum of monodeuterated compounds. This approach has now been applied to the study of 4'-(1-deuteropentyloxy)-4-biphenylcarbonitrile (5OCB-d1). The C-13 spectrum of this compound gives nine H-2-C-13 dipolar coupling constants for carbon ranging from one to six bonds away from the dueterium nucleus. The H-2 NMR and 5OCB-d1 gives the deuterium quadrupole coupling constant and the H-1- H-2 dipolar coupling constant for the alpha-CHD group. In addition, eleven 2-bond and two 3-bond H-1-C-13 dipolar coupling constants have been obtained for 4'-pentyloxy-4-biphenylcarbonitrile (non-deuterated 5OCB) by using the 2D C-13 method of proton-encoded local field spectroscopy.