Structural and property comparison between the di-piperidinyl- and di-pyrrolidinyl-substituted perylene tetracarboxylic diimides

Four compounds 1-4 connected with cyclic amino groups at the bay positions of perylenetetracarboxylic diimide (PDI) have been prepared and the isomers with 1,7- and 1,6-substituted PDIs were successfully separated by conventional column chromatography. The structures of 1,7-dipyrrolidinyl-substituted PDI (1) and 1,7-dipiperidinyl-substituted PDI (3) were further characterized by single crystal X-ray diffraction experiments. The crystal structure revealed that the small difference in the molecular structure has caused significant difference on the absorption and emission spectra as well as the electrochemical properties. The shorter bond length of C1-N3, together with the more sp2 hybrid atomic orbital characteristics of the nitrogen atom in pyrrolidine relative to those in piperidine is found to be responsible for this large property difference between 1 and 3. Copyright (C) 2010 John Wiley & Sons, Ltd.