Synthesis, physico-chemical studies and Hirshfeld surface analysis of a first 0-D Chlorozincophosphate, (H₂N(CH₂)₄NH(CH₂)₂NH₃Cl)ZnCl₂(HPO₄)

An original zero-dimensional chloro-substituted zincophosphate monomer, (H₂N(CH₂)₄NH(CH₂)₂NH₃Cl)Zn(HPO₄)Cl₂, was isolated by the reaction of zinc chloride (Zn²⁺, 2Cl⁻) with the amine, 1-(2-aminoethyl)piperazine, H₃PO₄ and HCl under ambient conditions. This phase crystallizes in the triclinic space group P-1 (No. 2) with the lattice parameters a = 8.834(2), b = 8.539(3), c = 11.163(2) Å, α = 93.58(2)°, β = 108.62(2)°, γ = 62.96(2)°, V = 707.3(4) Å³, Z = 2, R = 0.027 and Rw = 0.037. The tri-protonited organic cations are linked to the isolated chloride ions Cl⁻ through N–H⋯Cl and C–H⋯Cl hydrogen bonds, forming corrugated cationic layers extending parallel to (a b) plane. The inorganic framework of the title compound consists of a network of ZnO₃Cl and HPO₄ tetrahedral units linked by their oxygen vertices, forming isolated 4-membered rings. These anionic monomers, (Zn₂P₂O₈Cl₄H₂)⁴⁻, which are held by O–H⋯O hydrogen-bonding interactions, lie between the cationic layers to maximize the electrostatic interactions and are linked to (H₂N(CH₂)₄NH(CH₂)₂NH₃Cl)²⁺cations via N–H⋯O or N–H⋯Cl hydrogen bonds, forming a 3-D supra molecular structure. Hirshfeld surface analysis, Solid state NMR, Infrared spectroscopies and DTA/TGA analysis were also performed to characterize the title compound. Solid state³¹P and¹³C MAS NMR spectroscopy results were found to be in full agreement with the XRD results.