Preparation of a cyclic polyphenylene array for a chiral-type carbon nanotube segment

Abstract

DielsAlder reaction of cyclic biphenylyleneacetylene compound 3 with tetraphenylcyclopentadienone (5) realized the preparation of large-sized cyclic polyphenylene array 4. This is the first example of a cyclic polyphenylene array with a complete ring arrangement of a chiral-type CNT segment with (12,3)-structure. Transformation of 4 to the chiral-type CNT segment was attempted, but resulted in the formation of a complicated mixture probably due to the partial dehydrogenation and/or the partial elimination about the long alkyl chains. Rather efficient blue emission of the cyclic compounds 3 and 4 was discussed utilizing fluorescence quantum efficiencies and lifetimes both in their solid state and in their solution. By thermal analyses triple-melting behavior of 3 was clarified.