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From the system CuCl2–biq–NaN(CN)2 (biq is 2,2′-biquinoline), the binuclear molecular complex bis(μ-dicyanamido-κ2 N 1:N 5)bis[(2,2′-biquinoline-κ2 N,N′)(dicyanamido-κN 1)copper(II)], [Cu2(C2N3)4(C18H12N2)2] or [Cu2(biq)2(dca)2(μ1,5-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 CuII 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.

Ionic cobalt(II) complex [Co(dcnm)(H2O)(phen)2](dcnm) (1) (dcnm = dicyanonitrosomethanide, phen = 1,10-phenantroline) has been prepared by a diffusion technique. Its structure is formed by [Co(dcnm)(H2O)(phen)2]+ complex cation and free dcnm counterion in the lattice which acts as a hydrogen-bond acceptor to the hydrogen bonds from the water ligand coordinated to the Co atom. The Co atom is six-coordinated in the form of a distorted octahedron by two chelate phen molecules (one of them is disordered over two equivalent positions), one O-coordinated dcnm ligand and one water molecule which is cis-coordinated to O atom of dcnm ligand. The structure is stabilized by the system of hydrogen bonds and π–π interactions. Magnetic properties of 1 are dominated by a strong easy-plane anisotropy yielding to the energy difference between the two lowest Kramers doublets higher than 150 cm−1. Two field-induced relaxation channels were observed by AC susceptibility study and were shown to be dominated by the direct spin-phonon relaxation at low temperatures. One of the relaxation channels is identified to be mediated by the electron-nuclear interaction.

Blue crystals of {[Cu(bapa)]3[Cr(CN)6]2}n·6nH2O (bapa = bis(3-aminopropyl)amine) have been prepared, characterized and investigated by IR spectroscopy, X-ray structural analysis and measurement of magnetic response. Its unusual 3D crystal structure is formed by infinite Cu(II)–Cr(III) antiparallel chains (turned by 38°), which are connected into the third direction by additive [Cu(bapa)] moieties. Each Cu(II) atoms are five-coordinated by three nitrogen atoms originating from one bapa molecule and by two nitrogen atoms from two bridging cyanido groups thus forming more or less distorted square pyramids. High number of ν(C N) absorption bands observed in the IR spectrum is in agreement with higher number of different bridging cyanido groups in the structure. Magnetic properties are governed by a strong ferromagnetic exchange interaction between Cu(II) and Cr(III) ions, the major exchange interaction was estimated as JCr–Cu/kB = 64.3 K with average g-factors gCu = 2.12 and gCr = 2.00.

From the system CuCl

Five new ionic [Cu(L)2X]C(CN)3 (L = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen), X = Cl−, Br− or CH3COO−) complexes: [Cu(bpy)2Cl]C(CN)3 (1), [Cu(phen)2Cl]C(CN)3·H2O (2), [Cu(bpy)2Br]C(CN)3·H2O (3), [Cu(phen)2Br]C(CN)3·0.5H2O·0.5EtOH (4) and [Cu(phen)2Br0.7(CH3COO)0.3]C(CN)3·0.5H2O (5), have been synthesized and characterized by IR and UV–Vis spectroscopy. X-ray structural analysis revealed that the structures of all discussed compounds consist of [Cu(L)2X]+ complex cations and uncoordinated C(CN) 3 − counteranions; water molecules were found in 2, 3, 4 and 5; a molecule of ethanol was found in 4, too. The shapes of coordination polyhedra around the copper atoms, which are pentacoordinated by two bidentate bpy or phen molecules and Cl−, Br− or CH3COO− ligands monodentately coordinated in the equatorial plane, are distorted trigonal bipyramids. Structures of 1–5 are stabilized by weak π–π interactions and by hydrogen bonds. Magnetic properties of complexes 1–4 are characterized by the presence of weak antiferromagnetic exchange couplings.