Synthesis and Anion Binding Properties of a Novel 1,8-dipyrrolecarbazole Schiff-base

New anion receptor N-1,N-8-bis[1H-pyrro-2-yl-methylidene]-3,6-dichloro-9/1-carbazole-1,8-diamine (3) was synthesized and its binding properties towards anions (Cl-, Br-, AcO- and H2PO4-) investigated by UV/Vis spectroscopy. In order to find the most stable structure of receptor 3, geometries of all possible isomers of 3 were optimized by the DFT/B3LYP method. It has been determined that receptor 3 forms complexes with a 1:1 stoichiometry with all the studied anions and no significant selectivity with respect to anion geometry was found However, 1,8-dipyrrolecarbazole Schiff-base 3 binds oxoanions (H2PO4- and AcO-) more strongly than spherical halogenide (Cl- and Br-) anions.