Structural and Electrical Characterization of Polymeric Haloplumbate(II) Systems

Abstract

The synthesis and the structural, thermal, and electrical characterization of haloplumbate(II) systems are described. The counterions are diprotonated linear aliphatic amines, such as the 2-methylpentane-1,5-diamine (2meptH2) and propane-1,3-diamine (pnH2) dications. The (2meptH2)[PbCl4] and (2meptH2)[PbBr4] are isostructural, space group Cc, with a = 24.140(4) Å, b = 7.720(2) Å, c = 7.795(2) Å, β = 98.1(1)°, Z = 4 for the chlorine compound and a = 24.539(4) Å, b = 8.031(2) Å, c = 8.198(2) Å, β = 99.6(1)°, Z = 4 for the bromine compound; the (2meptH2)[Pb1.5I5] crystallizes in the triclinic P1̄ space group, with a = 11.803(3) Å, b = 12.565(3) Å, c = 8.494(8) Å, α = 106.2(1)°, β = 100.5(1)°, γ = 117.4(1)°, Z = 2; the crystals of (pnH2)[PbCl4] are orthorhombic, space group P212121, a = 19.247(4) Å, b = 7.862(2) Å, c = 7.581(2) Å, Z = 4; the (pnH2)2[Pb1.5Br7]·H2O crystallizes in the triclinic P1̄ space group, with a = 11.517(3) Å, b = 14.122(3) Å, c = 8.149(2) Å, α = 104.1(1)°, β = 109.8(1)°, γ = 77.5(1)°, Z = 2. Three different types of polymeric haloplumbate(II) systems were obtained: strictly monodimensional, (2meptH2)[Pb1.5I5], ribbonlike, (pnH2)2[Pb1.5Br7]·H2O, and perovskite-like structures, (pnH2)[PbCl4] and (2meptH2)[PbX4] (X = Cl, Br). Worthy of note is the presence of organic dications in their extended form, intercalated between the inorganic anions, which are at different distances, depending on the amine length. The nitrogen atoms of the ammonium cations interact with the inorganic anions forming a network of hydrogen bonds, which contribute to the crystal packing.