Thiocyanato-copper(II) complexes derived from a tridentate amine ligand and from alanine

Two thiocyanato-Cu(II) complexes including mononuclear dithiocyanato Cu(Me₃dpt)(NCS)₂ (1) and the polymeric 1D [Cu(d,l-Ala)(μ_N,S–NCS)(H₂O)] _n (2) were synthesized and structurally characterized (Me₃dpt = bis(N-methyl-3-propyl)methylamine, Ala = alaninate anion). The IR spectrum of complex 1 confirmed the N-bonding coordination mode of the thiocyanate groups, and its visible spectrum revealed the square pyramidal geometry around the central Cu²⁺ ion. Single X-ray crystallography of 1 showed that the Cu(II) center displays square pyramidal geometry with severe distortion toward trigonal bipyramidal environment. Complex 2 forms a 1-D polymeric chain with the NCS⁻ acting as a μ_N,S-ligand. A distorted SP geometry around the Cu²⁺ centers was achieved by the O and N atoms of alaninato anion, the aqua ligand and by the N and S atoms of the bridging thiocyanate groups. Hydrogen bonds of the type N–H···O, N–H···S and O–H···O are formed in this complex leading to the extension of the 1D chain to a supramolecular network.