Self-assembly of bis(pyrrol-2-yl-methyleneamine)s bridged by flexible linear carbon chains

Two linear bis(pyrrol-2-yl-methyleneamine)s linked by a carbon chain, –(CH2)n–, n=2, 4, were synthesized in high yields by condensation of 2-formylpyrrole with the corresponding diamines. Self-assembly of the resulting bis(pyrrol-2-yl-methyleneamine) ligands with Zn(II) gave double-stranded helicates in excellent yields. Their structures were characterized by MS, 1H NMR, 13C NMR, UV–Vis spectroscopic studies, and were confirmed by an X-ray crystal analysis. In CH2Cl2, both complexes and displayed moderate fluorescence.