Distinction between homochiral and heterochiral dimers of 1-aza[n]helicenes (n=1-7) with alkaline cations

A theoretical study of the chiral distinction between the homochiral and heterochiral dimers of the 1-aza[n]helicenes, with n = 1-7, glued with lithium, sodium, and potassium cations has been carried out by means of DFT calculations up to M05-2x/6-311+G(d) computational level. The electronic characteristic of the isolated helicenes has been explored. The chiral distinction is dependent on the size of the helicene and the cation used with the largest values obtained for the 1-aza[6]helicene bound to lithium cation. (C) 2010 Elsevier Ltd. All rights reserved.