Crystal structure of tetraaquabis(5-(4-carboxybenzyloxy)isophthalato)- tricalcium(II) tetrahydrate, Ca3(H2O)4(C16H9O7)2 · 4H2O

Abstract

Source of materialAll reagents and solvents employed were commercially available andusedasreceivedwithoutfurther purification.The compound of 5-(4-carboxybenzyloxy)isophthalic acid (CIA) was synthesized by the procedure reported in the literature [1]. The mixture of CIA (0.05 g, 0.16 mmol), NaOH (0.02 g, 0.48 mmol) ,CaCl 2 × 2H 2 O(0.0263 g, 0.237 mmol) and 10 mL water was sealed in a 25 mL Teflon-lined stainless reactor and heated at 130°C for 72 h under autogeneous pressure. With cooling to room temperature, colourless crystals suitable forX-ray diffraction were obtained. Experimental detailsAllh ydrogena toms on carbonsw ereg enerated geometrically with d(C-H)=0.93-0.97 Å, and U iso (H) =1.2 U eq (C) for atoms of CH 2 groups and aromatic ring. Hydrogen atomsofthe water molecules were not localized. DiscussionRecently, the rational design and synthesis of novel coordination polymers have attracted intense attention in the field of supra-molecularchemistry and crystal engineering. We have seen arelated report [2], it has similarly used CIA as an organic ligand with the different metal ion Cd(II) to forma3D structure in which the coordination mode of CIA is not the sameasthat in this paper. In the asymmetric unit there are two crystallographically independent Ca(II) centers with different coordinations. The Ca1 is seven-coordinated by six Oatomsfrom four independent ligands CIA and one water molecule, showing apentagonal bipyramidal coordination. The bond lengths d(Ca-O) arei nt he range of 2.236(2)-2.5481(2) Å. Ca2 is six-coordinated by four Oa toms from four independent CIA ligands in the equatorial positions and two water molecules in the apical positions of an octahedron. The bond lengths d(Ca-O) are 2.3113(2) and 2.334(2) Å, respectively.EachCIA anion connects five Ca(II) (three Ca1and two Ca2)atoms to form alayer.The layers are linked by carboxylate groups of CIAa nionst og enerateat hree-dimensional framework.