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Synthesis, Characterization, and Spectroscopy of 4,7,12,15-[2.2]Paracyclophane Containing Donor and Acceptor Groups:  Impact of Substitution Patterns on Through-Space Charge Transfer

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journal contribution
posted on 10.04.2002, 00:00 by Glenn P. Bartholomew, Guillermo C. Bazan
This paper reports the synthesis of 4,7,12,15-tetra(4‘-dihexylaminostyryl)[2.2]paracyclophane (1), 4-(4‘-dihexylaminostyryl)-7,12,15-tri(4‘ ‘-nitrostyryl)[2.2]paracyclophane (2), 4,7-bis(4‘-dihexylaminostyryl)-12,15-bis(4‘ ‘-nitrostyryl)-[2.2]paracyclophane (3), 4,7,12-tris(4‘-dihexylaminostyryl)-15-(4‘ ‘-nitrostyryl)[2.2]paracyclophane (4), 4,15-bis(4‘-dihexylaminostyryl)-7,12-bis(4‘ ‘-nitrostyryl)[2.2]paracyclophane (5), and 4,12-bis(4‘-dihexylaminostyryl)-7,15-bis(4‘ ‘-nitrostyryl)[2.2]paracyclophane (6). These molecules represent different combinations of bringing together distyrylbenzene chromophores containing donor and acceptor groups across a [2.2]paracyclophane (pCp) bridge. X-ray diffraction studies show that the lattice arrangements of 1 and 3 are considerably different from those of the parent chromophores 1,4-bis(4‘dihexylaminostyryl)benzene (DD) and 1,4-di(4‘-nitrostyryl)benzene (AA). Differences are brought about by the constraint by the pCp bridge and by virtue of chirality in the “paired” species. The absorption and emission spectra of 16 are also presented. Clear evidence of delocalization across the pCp structure is observed. Further, in the case of 2, 3, and 4, emission from the second excited state takes place.