Isomerism of bis(7-azaindolyl)methane

Three isomers of bis(7-azaindolyl)methane have been synthesized and fully characterized. Isomers 1 and 2 contain 7-azaindolyl groups that are bound to the CH(2) group through nitrogen atoms. However, 1 contains two "normal" 7-azaindolyl groups, whereas 2 contains both a normal 7-azaindolyl group and a tautomer form of 7-azaindolyl. The third isomer 4 contains two 7-azaindolyl groups that are bound to the CH(2) group through the carbon atom at the position-3. These three isomers show distinct absorption and emission spectra, attributable to the different forms of 7-azaindolyl groups in the isomers, as indicated by the results of ab initio calculations. [structure: see text]