INFRARED LINEAR DICHROISM ON 1,5-DIPHENYL-1,3,5-PENTANETRIONE ALIGNEDIN STRETCHED POLYETHYLENE

The title compound, aligned in uniaxially stretched polyethylene (PE) sheets has been investigated by infrared linear dichroism (LD) spectro scopy. It has been possible to observe 38 vibrational transitions and to determine orientation factors for several of the transition moment directions. The only reasonable interpretation of the experimental dat a is that the observed molecule has C-2v-symmetry and that the compoun d adopts the symmetrical dienol form when dissolved in PE. The IR LD s pectra do not indicate the presence of keto or enol forms, in contrast with the results of previous IR investigations using Nujol mull as th e solvent.