Coordinative capabilities of substituted propane-1,3-diamine: Zinc(II) halide adducts of 2,2-dimethylpropane-1,3-diamine.

A series of compounds of formula Zn(dmpd)nX2· mH2O (dmpd = 2,2-dimethylpropane-1,3-diamine, X = Cl, Br, I; n = 2, m = 0; n = 3, m = 1) has been prepared and studied by means of spectroscopic (IR and Raman) and structural investigations. The [Zn(dmpd)2]I2 (I) compound crystallizes in the tetragonal P42/nmc space group, with two formula units in a cell of dimensions: a = b = 8.417(2), c = 12.726(2) Å. The structure consists of an ionic packing of iodide anions and of discrete [Zn(dmpd)2]2+ cations, where the Zn atoms are tetrahedrally coordinated to four nitrogen atoms of two chelating amine molecules. The [Zn(dmpd)3]Cl2·H2O (II) compound crystallizes in the triclinic space group P1, with Z = 2 and cell of dimensions: a = 9.021(2), b = 12.087(3), c = 13.785(3) Å, α = 59.01(2), β = 70.35(2), γ = 76.01(2)°. The crystal consists of an ionic packing of discrete [Zn(dmpd)3]2+ cations and chloride anions plus two clathrate water molecules per unit cell. The Zn atom presents a trigonal bipyramidal geometry, being surrounded by four nitrogen atoms of two chelating dmpd molecules and one nitrogen of a monodentate dmpd ligand. The structures were solved by conventional Patterson and Fourier methods and refined by full matrix least-squares to R and Rw of 0.053 and 0.073, and 0.040 and 0.046 for I and II respectively. The ZnN stretching vibrations are discussed and assigned in the light of the determined structures.