Crystal structure and vibrational spectra of polyamine-copper(II) complexes

The structures of [Cu(en)(H₂O)₂]SO₄ (I), [Cu(en)₂](NO₃)₂ (II) and [Cu(trien)I]I (III) have been determined by single crystal X-ray diffraction. ComplexI is monoclinic, space group C2/c, with unit cell parametera=7.232(1),b=11.725(2),c=9.768(1), =105.50(1)°, andZ=4. ComplexII is also monoclinic, space group P2₁/a, witha=7.978(2),b=9.982(4),c=8.218(3), =111.11(2)°, andZ=2. ComplexIII is orthorhombic, space group P2₁2₁2₁, witha=8.098(1),b=11.902(1),c=13.682(2), andZ=4. The structures were solved by direct methods and refined by full-matrix least-squares to finalR values of 0.031, 0.043 and 0.036 for complexesI, II, andIII, respectively. ComplexesI andII show an octahedral coordination geometry. ComplexIII shows a square pyramidal coordination geometry. ComplexI forms infinite monodimensional chains where the SO₄^2– ions acts as a bridge between two neighboringen molecules. The vibrational spectra of these complexes agree well with their crystal structures. Structure and stability of seven other related Cu(II) complexes of (trien), (dien)₂, (en)₂ and (en) are inferred in this study.