Thiocyanato-bridged Copper Research Articles

Exchange coupling in a thiocyanato-bridged copper(II) chain: Computational approach to magnetostructural correlations

In this article we report the synthesis and magneto-structural characterization of two new copper(II) compounds with thiocyanato and methyl(2-pyridil) ketone oxime (mpkOH), namely [Cu(NCS)(mpkO)(mpkOH)] (1) and [Cu(µ-NCS)(NCS)(mpkOH)]n (2). Compound 1 is a mononuclear complex that crystallizes as discrete units. Conversely, compound 2 is a single equatorial-axial end-to-end thiocyanato bridged polymeric chain of Cu(II) with the oxime as a co-ligand. The coordination geometry around the Cu(II) centers is distorted square pyramidal for 1 and 2. The magnetic susceptibility data for 2 reveal weak intrachain antiferromagnetic coupling, with J value −0.74(3) cm−1 and g = 2.10(1). The application of computational tools to a binuclear model of 2 allowed us to unveil the structural basis that modulates the magnetic behavior of this type of thiocyanato-bridged Cu(II) chains. The results suggest that although small values of J are expected, the strongest ferromagnetic interactions can be obtained by including co-ligands that trigger a squared-based pyramidal-to-trigonal bipyramidal distortion of the coordination polyhedra.

Crystal Growth and Structural Characterization of a Thiocyanato-Bridged Copper(I/II) Mixed-Valence Coordination Polymer

A new mixed-valence coordination polymer [Cu3(SCN)4(DMSO)2] n (SCN– = thiocyanato and DMSO = dimethyl sulfoxide) was prepared and characterized by single crystal X-ray diffraction method. The in situ formation of thiocyanate during the synthesis induces reduction of a part of Cu(II) to Cu(I). The three-dimensional structure of the binuclear thiocyanato bridged compound provided an example of pseudohalide materials containing two different environments for both copper centers.

Synthesis, crystal structure, photoluminescent and antimicrobial properties of a thiocyanato-bridged copper(II) coordination polymer

AbstractA Cu(II) 1D polymer with mixed ligands (SCN− and pyridine) has been synthesized and characterized by elemental analyses, IR, UV–visible and TG-DTA analytical techniques. The crystal structure was determined by single-crystal X-ray diffraction analyses. The complex crystallizes in the triclinic crystal system with space group P1¯ with one formula unit. Each Cu(II) atom is six coordinate with two N atoms of two pyridine molecules, two N atoms and two S-atoms from bridging SCN anions giving a distorted octahedral geometry with a CuS2N4 chromophore. The spectroscopic, photoluminescent and the antimicrobial activities of the synthesized complex were investigated.

A thiocyanato-bridged copper(i) cubane complex and its application in palladium-catalyzed Sonogashira coupling of aryl halides

Reaction of copper(I) thiocyanate with 1,1'-bis(di-tert-butylphosphino) ferrocene (dtbpf) in a 2:1 molar ratio in DCM-MeOH (50:50 V/V) afforded a tetranuclear copper(I) complex [Cu4(μ3-SCN)4(κ(1)-P,P-dtbpf)2] (1) with a cubane-like structure. Complex 1 was shown to be an efficient catalyst in comparison to CuI in the Sonogashira reaction. The coupling products were obtained in high yields by using Pd loadings of 0.2 mol% as well as complex-1 of 0.1 mol%.

Synthesis and crystal structure of polymeric thiocyanato-bridged copper(II) complex with 4-nitro-2-[(2-piperidin-1ylethylimino)methyl] phenolate

A polymeric thiocyanato-bridged Schiff base copper(II) complex [Cu(L)(NCS)]n, where L is 4-nitro-2-[(2-piperidin-1-ylethylimino)methyl]phenolate, has been synthesized and structurally characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. The complex crystallizes in the monoclinic space group P21 with a = 8.527(5), b = 10.296(6), c = 9.697(6) A, β = 103.77(2)°, V = 826.8(8) A3, Z = 2. In the complex, the Cu atom is in a square pyramidal coordination with one O and two N donor atoms of the Schiff base ligand and with one thiocyanate N atom, defining the basal plane, and with one symmetry related thiocyanate S atom occupying the apical position. The thiocyanate ligand links the Cu atoms through the end-to-end bridging mode.

Preparation, crystal structures and magnetic properties of three thiocyanato-bridged copper(II) complexes with 2,2′-biimidazole or 2-(2′-pyridyl)imidazole as terminal ligands

The synthesis, crystal structures and variable temperature magnetic investigation of three new thiocyanato-bridged copper(II) complexes with 2,2′-biimidazole (H 2bim) or 2-(2′-pyridyl)imidazole) (pyim) as coligands, {[Cu(H 2bim) 2][Cu(H 2bim)(NCS) 2(SCN) 0.6667(NO 3) 0.3333] 2} · 2H 2O ( 1), [Cu(H 2bim)(NCS) 2] n ( 2) and [Cu(pyim)(NCS) 2] n ( 3) are reported. Complex 1 contains centrosymmetric trinuclear species where central [Cu(2)(H 2biim) 2] 2+ cations and peripheral [Cu(1)(H 2biim)(NCS) 2(SCN)] − anions are linked through single end-to-end thiocyanato bridges. Complexes 2 and 3 are made up of neutral zigzag chains of copper(II) ions linked by single ( 2) and double ( 3) end-to-end thiocyanato bridges. A bidentate H 2bim ligand ( 2) or pyim ( 3) and a terminal N-thiocyanate group ( 2) complete the coordination spheres around each copper atom. The values of the intramolecular ( 1) and intrachain ( 2 and 3) copper–copper separations are 5.6143(5) ( 1), 5.6744(3) ( 2) and 6.0797(11) Å ( 3). Magnetic susceptibility measurements for 1– 3 in the temperature range 1.9–295 K show the occurrence of weak intramolecular ( 1) and intrachain ( 2 and 3) antiferromagnetic interactions [ J = −0.10 ( 1), −0.24 ( 2) and −0.03 cm −1 ( 3), the Hamiltonians used being H ˆ = - J ( S ˆ 1 · S ˆ 2 + S ˆ 2 · S ˆ 3 ) ( 1) and H = − J∑ i ( S ˆ i · S ˆ i + 1 ) ( 2 and 3)]. The magnitude and nature of these magnetic interactions are discussed in the light of the respective structures and they are compared with those reported for related systems.