Coordination Helical Nanotubes Constructed by Metal(II) Ions with the Indicator Chrome Pure Blue BX

A treatment of MCl2 (M = Zn, Ni, Co, Mg) with the indicator chrome pure blue BX (Na2cpb) yielded new coordination polymers, {[M(H2O)6][M(cpb)2(H2O)2]·(H2O)9}n (M = Zn (1), Ni (2), Co (3)) and {[Mg(H2O)6][Mg(cpb)2(H2O)2]·(H2O)6}n (4). These compounds, which are crystallographically isostructural, show helical 1D nanotube structures.