Crystal structure of NaZn(BTC)(H2O)4·1.5H2O (BTC = benzene-135-tri­carb­oxy­l­ate): a heterometallic coordination compound

摘要

The title coordination polymer, poly[[μ-aqua-tri­aqua­(μ3-benzene-1,3,5-tri­carboxyl­ato)sodiumzinc] sesquihydrate], {[NaZn(C9H3O6)(H2O)4]·1.5H2O}n, was obtained in ionic liquid microemulsion at room temperture by the reaction of benzene-1,3,5-tri­carb­oxy­lic acid (H3BTC) with Zn(NO3)2·6H2O in the presence of NaOH. The asymmetric unit comprises two Na⁺ ions (each located on an inversion centre), one Zn²⁺ ion, one BTC ligand, four coordinating water mol­ecules and two solvent water molecules, one of which is disordered about an inversion centre and shows half-occupation. The Zn²⁺ cation is five-coordinated by two carboxyl­ate O atoms from two different BTC ligands and three coordinating H2O mol­ecules; the Zn—O bond lengths are in the range 1.975 (2)–2.058 (3) Å. The Na⁺ cations are six-coordinated but have different arrangements of the ligands: one is bound to two carboxyl­ate O atoms of two BTC ligands and four O atoms from four coordinating H2O mol­ecules while the other is bound by four carboxyl­ate O atoms from four BTC linkers and two O atoms of coordinating H2O mol­ecules. The completely deprotonated BTC ligand acts as a bridging ligand binding the Zn²⁺ atom and Na⁺ ions, forming a layered structure extending parallel to (100). An intricate network of O—H⋯O hydrogen bonds is present within and between the layers.