Coordination chemistry of the new ligand 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol (HPClNOL) with copper(II). X-ray crystal structure, spectroscopic and electrochemical properties of the complex [Cu(HPClNOL)(CH3CN)](ClO4)2

The crystal structure, electrochemical behaviour and spectroscopic properties (FT-IR, UV–vis and EPR) of the mononuclear complex [Cu(HPClNOL)(CH3CN)](ClO4)21, are reported. The new tetradentate ligand, HPClNOL, 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, reacts with 1 equiv. of [Cu(OH2)6](ClO4)2, in methanol, to give 1, which crystallizes as blue monoclinic crystals, space group P21/c with a=14.906(3) Å, b=11.371(2) Å, c=14.113(3) Å, β=103.86(3)°, V=2322.4(8) Å3 and Z=4. In 1, the copper center is pentacoordinated, showing a distorted square pyramidal geometry. The electronic spectrum indicates that, in acetonitrile, the copper atom becomes hexacoordinated (λmax(ε) 621 nm (87 dm3 mol−1 cm−1). Frozen solution EPR spectra of 1 in pure acetonitrile (A‖=190 G, g‖=2.24) and of 1 in acetonitrile/tetrabutylammonium perchlorate solution (A‖=185 G, g‖=2.25) indicates a hexacoordinated environment for the copper(II) center. Complex 1 shows a quasi-reversible redox process at 70 mV vs NHE, which is attributed to Cu(II)/Cu(I) redox couple.