Coordinative capability of propane-1,3-diamine: spectroscopic and structural properties of a complex of formula [Cd(pnH)4Cl2]Cl4

The compound [Cd(pnH)4Cl2]Cl4 (pn = propane-1,3-diamine) has been prepared and studied by means of spectroscopic (IR and Raman) and structural investigations. It crystallizes in the tetragonal P4nc space group (No. 104), with two formula units in a cell of dimensions: a = b = 11.972(4), c = 9.129(4) angstrom. The structure consists of an ionic packing of chlorine anions and of discrete [Cd(pnH)4Cl2]4+ cations; the Cd atoms are octahedrally coordinated to four nitrogen atoms of four distinct monoprotonated diamines and to two chlorine atoms in trans position to each other, showing very loose Cd-Cl bonding interactions (2.680(3) and 2.884(2) angstrom). The protonated ends of the propane-1,3-diamines interact with the non-coordinated chlorine ions via hydrogen bonding. The Cd-N and Cd-X stretching vibrations are discussed and assigned in the light of the known structures.