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From the system CuCl 2 -biq-NaN(CN) 2 (biq is 2,2'-biquinoline), the binuclear molecular complex bis(μ-dicyanamido-κ 2 N 1 :N 5 )bis[(2,2'-biquinoline-κ 2 N,N')(dicyanamido-κN 1 )copper(II)], [Cu 2 (C 2 N 3 ) 4 (C 18 H 12 N 2 ) 2 ] or [Cu 2 (biq) 2 (dca) 2 (μ 1,5 -dca) 2 ] (1) [dca is dicyanamide, N(CN) 2 - ] was isolated and characterized by crystal structure analysis, and spectral, thermal and magnetic measurements. IR spectroscopy confirmed the presence of the biq and dca ligands in 1. Its solid-state structure consists of discrete centrosymmetric binuclear copper(II) units with double end-to-end dca bridges. Each Cu II atom is in a distorted square-pyramidal environment with the equatorial plane formed by two nitrile N atoms from bridging dca groups, one of the two N atoms of the chelate biq molecule and one nitrile N atom from a terminal dca ligand, whereas the second biq N atom occupies the axial position. Thermal decomposition of 1 in an air atmosphere proceeds gradually, with copper(I) cyanide being the final decomposition product. Magnetic measurements revealed the formation of alternating spin chains and a relatively strong exchange interaction within the binuclear units was also confirmed by Broken Symmetry DFT (density functional theory) calculations.

The complex (2,2'-biquinoline-κ 2 N,N')(carbamoylcyanonitrosomethanide-κ 2 N,O)chloridocopper(II) acetonitrile monosolvate, [Cu(C 3 H 2 N 3 O 2 )Cl(C 18 H 12 N 2 )]·CH 3 CN or [Cu(ccnm)Cl(biq)]·acn (acn is acetonitrile, biq is 2,2'-biquinoline and ccnm is carbamoylcyanonitrosomethanide), (I), was prepared as a result of nucleophilic addition of water to the dicyanonitrosomethanide ion in the presence of Cu II and biq. IR spectroscopy confirmed the presence of ccnm, biq and acn in (I). The solid-state structure consists of the neutral complex containing ccnm and biq ligands, coordinated to the Cu II atom in a bidendate chelating manner, and a chloride ligand, resulting in a distorted tetragonal pyramidal coordination of Cu II . The asymmetric unit is supplemented by one molecule of solvated acn which, along with the nitrile group of ccnm, serves as an acceptor in intermolecular hydrogen bonding, creating infinite chains along the b axis. Magnetic measurements revealed a paramagnetic behaviour with a very small Weiss temperature Θ = -0.32 K and high anisotropy of the g tensor (g x = 2.036, g y = 2.120 and g z = 2.205).