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The anhydride 26 used as starting material was made from 2,3-dicyanohydroquinone via a series of treatments, such as oxidation, Diels-Alder cycloaddition, enolization, methylation, basic hydrolysis, and acidic dehydration. The condensations of anhydride 26 with conjugated amines were successfully achieved under specific concentration or equivalent conditions to give both [1+1] and [2+1] imide products. The conformational isomers of imide 40, 41, 44 were also detected in our characterizations. In dynamic NMR studies, the interconversions of the conformational isomers of each compound were obviously observed, because the increasing temperature technique overcame the steric hindrance of single bond rotations. The phenomena shown in NMR spectra provided us reasonable evidences for the isomers we found.
Except compounds 40, 41, and 44 , we found that there exists enantiomers in equal ratio inside each unit cell, in the X-ray diffraction characterization for each imide product. In the solid-state structural analysis of each diimide compound, we observed the methylenes on the bridges were trans to one another, and the isoindole planes of either sides of the imide molecules were coplanar with one another. By these the crystalline packing pattern shown, we may estimate that the observed conformations of imides correspond to most steady energetic requirements for crystalline packings.
Imide 37, 38, 40, and 45, were also reacted with ruthenium carbene catalyst to undergo ring-opening metathesis polymerization (ROMP) in our researches. The polymerization feature of the four polymers obtained was also analyzed to give respective PDI value. All of the PDI values are lower than 1.4, these ROMP was classified as typical active polymerization.
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