Interplay of hydrogen bonding and coordination modes in diaquabis(8-hydroxy-7-iodoquinoline-5-sulfonato)calcium(II) monohydrate

Abstract

In the crystal structure of the title compound, [Ca(C9H5INO4S)2(H2O)2]·H2O, the asymmetric unit consists of one calcium ion, two organic ligands, two coordinated water mol­ecules and one uncoordinated water mol­ecule. The calcium ion has a pentagonal-bipyramidal geometry, formed by O atoms of three different sulfonate groups, deprotonated O atoms of two different oxine rings and two water mol­ecules. In the ligands of type I, two O atoms of the sulfonate group are involved in coordination, whereas in type II ligands, only one O atom is involved. Ligands of type I are stacked over one another, each pair of adjacent members of the stack being related by an inversion centre. Ligands of type II are also stacked in a similar manner. Both of these molecular stacks are cross-linked by Ca—O(sulfonate) and Ca—O(quinolinol) bonds, leading to a three-dimensional network. This network is further stabilized by a number of O—H⋯O and N—H⋯O hydrogen bonds.