Copper(II)–malonato coordination frameworks with ethanolammonium cations. Synthesis, spectral, thermal and structural characterization of trans-[Cu(mal) 2(meaH) 2] and {(deaH) 2[Cu(μ-mal) 2]·H 2O} ∞ (meaH=monoethanolammonium, deaH=diethanolammonium and mal=malonate)

Abstract

Two isomorphous malonato–copper(II) complexes, [Cu(mal) 2(meaH) 2] and {(deaH) 2[Cu(μ-mal) 2]·H 2O} ∞ (meaH=monoethanolammonium, deaH=diethanolammonium and mal=malonate), have been prepared and characterized by elemental analyses, IR, UV–vis, magnetic measurements and single crystal X-ray diffraction. The mononuclear complex crystallizes in the monoclinic space group P2 1/ n, with a=8.6630(8) Å, b=7.5122(5) Å, c=11.4390(10) Å, β=95.530(7) and Z=2. The polymeric malonato-bridged copper(II) complex crystallizes in the monoclinic space group P2 1/ c, with a=26.5169(14) Å, b=8.2544(5) Å, c=9.5243(5) Å, β=96.256(4) and Z=4. The monomeric complex consists of individual units in which copper(II) sits on the inversion center and is octahedrally coordinated by two bidentate mal and two monodendate meaH ligands. The structural units are joined into the framework by the system of hydrogen bonds. The polymeric complex composed of two-dimensional chains containing the mal bridged [Cu(mal) 2] 2− ions and each mal ligand simultaneously exhibits chelating bidentate (at one copper atom) and bridging (at the adjacent copper atom) coordination modes. The intrachain Cu1⋯Cu2 separation is 6.302(4) Å. The deaH cations are not coordinated to copper(II) and occupy the voids of the frame work, together with the lattice water molecules. The IR spectra and thermal decompositions of both complexes are described in detail.