Linear Trinuclear Copper Research Articles

Synthesis, structures of cobalt/copper complexes and magnetic property of copper complex with the mixed ligands 5-nitro-1,3-benzenedicarboxylic acid and imidazole

Two one-dimensional cobalt (II) and copper (II) complexes, [Co(5-nbdc) 2(imH) 2] n ( 1) and [Cu 3(5-nbdc) 2(OH) 2(imH) 2] n ( 2) (5-nbdcH 2 = 5-nitro-1,3-benzenedicarboxylic acid and imH = imidazole) have been synthesized and structurally characterised. Complex 2, a molecular ladder consisting of the linear trinuclear copper (II) subunits and featuring the mixed μ-hydroxo and μ-carboxylato bridges, indicated a strong intra-trimer antiferromagnetic coupling ( J/ k = −43.8 K) and a weak inter-trimer antiferromagnetic coupling ( J′/ k = −2.5 K) with the corresponding g value 2.011.

Structure and magnetism of two new linear trinuclear copper(II) clusters obtained from the tetradentate N 2O 2 ligand bis(2-hydroxybenzyl)-1,3-diaminopropane

Reaction of bis(2-hydroxybenzyl)-1,3-diaminopropane (H 2bhbd) with copper(II) perchlorate and copper(II) chloride in methanol, respectively, leads to linear trinuclear clusters, namely [Cu 3(bhbd) 2(CH 3OH) 2(ClO 4) 2] ( 1) and [Cu 3(bhbd) 2Cl 2](CH 3OH) 4 ( 2). These coordination compounds were characterized by X-ray crystallography, UV–Vis, IR and EPR spectroscopy, and magnetic susceptibility measurements. Both complexes have a linear trinuclear array of copper ions bridged by means of phenolato O atoms and separated by a distance of 2.985(4) Å ( 1) and 2.937(4) Å ( 2). Strong antiferromagnetic interactions between these adjacent Cu II ions govern the magnetochemistry of 1 ( J = −303(1) cm −1) and 2 ( J = −482(3) cm −1) resulting in S = 1/2 ground states fully populated below 150 K. A correlation between the interaction parameter J and the angles within the trinuclear clusters is proposed.

Synthesis, crystal structure and magnetism of centrosymmetric linear trinuclear copper(II) complex of pyridine nitronyl nitroxide derivative

Novel stable dark-green solid adducts ( 2) were isolated from the reaction of 2-(4,4,5,5-tetramethyl-3-oxylimidazoline-1-oxide)-5-bromopyridine ( 1) with copper(II)-hexafluoroacetylacetonate hydrate (Cu(hfac) 2 · xH 2O), namely [ 1 2 • {Cu(hfac) 2} 3]. The X-ray structure revealed that, the complex is linear and centrosymmetric in the triclinic P 1 ̄ space group. The striking feature of the complex is, the presence of two types of copper coordination geometries with the radical 1, a distorted octahedron at the center and two terminal octahedron structures, where the copper and the nitronyl nitroxide oxygen binding is stronger in the latter case due to “chelation effect”. The central copper is surrounded by O 6 donor sets and the terminal coppers are surrounded by N,O 5 donor sets. The three copper ions in the complex are collinear with shortest intramolecular metal–metal distance ca. 7.75 Å. The angles between Cu–O–N also differ considerably due to the different overlapping modes of nitronyl nitroxide oxygen with copper, for chelating type it is 111.25° and for the non-chelating one it is 142.85°. Two exchange couplings are possible for this kind of system. The magnetic behavior shows that the coupling is antiferromagnetic between the radical and the terminal coppers, with J 1=−440 cm −1 and weakly ferromagnetic between the central copper and the neighboring radicals with J 2=10 cm −1.

Structural and Magnetic Characterization of a Linear Trinuclear Copper Complex Formed through Ligand Sharing

AbstractReaction of bis(2‐hydroxybenzyl)‐1,3‐diamino‐2‐propanol (H2bhbdp) with copper perchlorate in methanol leads to the assembly of a trinuclear complex with the general formula [Cu3(bhbdp)2(CH3OH)2(ClO4)2] (1). The complex was characterized by X‐ray crystallography, Ligand Field, IR and ESR spectroscopy, and magnetic susceptibility. The structure of the complex contains a linear trinuclear array of copper ions [the Cu(1)−Cu(2)−Cu(1a) angle is 180° by symmetry], in octahedral, square planar and octahedral environments, respectively. The external Cu1 and Cu1a centers are coordinated by two amine nitrogens, two phenolate oxygen donors, one methoxide oxygen and one oxygen from a perchlorate, while the central Cu2 is coordinated by four phenolate oxygens through ligand sharing. A strong antiferromagnetic interaction between the adjacent CuII ions dominates the magnetic properties of 1 leading to an S = 1/2 ground state which is fully populated below 150 K. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Rational Design of a Ferromagnetic Trinuclear Copper(II) Complex with a Novel in‐situ Synthesised Metalloligand

AbstractAn interesting ferromagnetic linear trinuclear copper(II) compound containing an in‐situ synthesised functional ligand has been rationally obtained and crystallographically characterised, confirming a new route to magnetic polynuclear clusters. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Two pyrazolato-bridged, linear trinuclear Cu(II) complexes. Crystal structures and magnetic properties

The single-crystal X-ray structures of two new linear trinuclear copper(II) complexes of 3,5-pyrazoledicarboxylic acid (H 3L) are reported, viz. [Cu 3(L) 2(Me 2en) 2(H 2O) 2]·(H 2O) 8 ( 1) and [Cu 3(L) 2(MeOH) 6(H 2O) 4] ( 2), with Me 2en is N, N-dimethylethylenediamine. Both complexes are trinuclear and have been obtained from a precursor ligand, through copper-induced amide hydrolysis. In 1, the central copper ion is in a distorted square-planar environment and the two outer copper ions are in a distorted square-pyramidal environment. All three copper ions in 2 are six-coordinated in an elongated octahedral environment. A weak, broad EPR signal centered around g=3.5, indicative for an S=3/2 state, is observed and confirms both complexes to be trinuclear. Magnetic susceptibility measurements of 1 and 2 from 4 to 300 K indicate a weak anti-ferromagnetic exchange coupling, with J values of −15 and −19 cm −1, respectively.

Oxidative cleavage of DNA by a new ferromagnetic linear trinuclear copper(II) complex in the presence of H2O2/sodium ascorbate.

A new trinuclear copper(II) complex has been synthesized and structurally characterized: [Cu(3)(L)(2)(HCOO)(2)(OH)(2)](infinity) (HL = (N-pyrid-2-ylmethyl)benzenesulfonylamide). In the complex, the central copper ion is six-coordinated. The coordination spheres of the terminal copper atoms are square pyramidal, the apical positions being occupied by a sulfonamido oxygen of the contiguous trimer. As a consequence, the complex can be considered a chain of trinuclear species. The three copper atoms are in a strict linear arrangement, and adjacent coppers are connected by a hydroxo bridge and a bidentate syn-syn carboxylato group. The mixed bridging by a hydroxide oxygen atom and a bidentate formato group leads to a noncoplanarity of the adjacent basal coordination planes with a dihedral angle of 61.4(2) degrees. Susceptibility measurements (2-300 K) reveal a strong ferromagnetic coupling, J = 79 cm(-1), leading to a quartet ground state that is confirmed by the EPR spectrum. The ferromagnetic coupling arises from the countercomplementarity of the hydroxo and formato bridges. The trinuclear complex cleaves DNA efficiently, in the presence of hydrogen peroxide/sodium ascorbate. tert-Butyl alcohol and sodium azide inhibit the oxidative cleavage, suggesting that the hydroxyl radical and singlet oxygen are involved in the DNA degradation.

Different oxidation states of copper(I, I/II, II) thiocyanate complexes containing 1,2,4-triazole as a bridging ligand: syntheses, crystal structures, and magnetic properties of 2-D polymer Cu I(admtrz)SCN, linear trinuclear [CuI2CuII(admtrz)6(SCN)2](ClO4)2, and triangular trinuclear [CuII3(admtrz)4(SCN)3(mu3-OH)(H2O)](ClO4)2.H2O (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole).

Copper thiocyanate compounds with three different oxidation states, Cu(I)(admtrz)SCN (1), [Cu(I)(2)Cu(II)(admtrz)(6)(SCN)(2)](ClO(4))(2) (2), and [Cu(II)(3)(admtrz)(4)(SCN)(3)(mu(3)-OH)(H(2)O)](ClO(4))(2).H(2)O (3), have been synthesized and characterized (admtrz = 4-amino-3,5-dimethyl-1,2,4-triazole). Compounds 1 and 3 crystallize in the space group Pbca of the orthorhombic system with eight formula units in cells of dimensions a = 8.0221(2) A, b = 32.3844(1) A, c = 13.5659(3) A, R1/wR2 = 0.0595/0.1674 for compound 1 and a = 21.501(3) A, b = 18.382(2) A, c = 21.526(2) A, R1/wR2 = 0.0638/0.1519 for compound 3. Compound 2 crystallizes in the space group C2/c of the monoclinic system with four formula units in cells of dimensions a = 18.772(4) A, b = 11.739(2) A, c = 22.838(5) A, beta = 91.11(3) degrees, R1/wR2 = 0.0482/0.1265. The layered-type structure of 1 can be regarded as constructed from the tetranuclear copper units double bridged by one of the two unique thiocyanate and admtrz ligands, which are bridged by the other unique thiocyanate ligands to form a two-dimensional layered structure along the a and b directions. The linear trinuclear copper cation in mixed-valence compound 2 consists of one two-valence copper and two one-valence copper atoms which are bridged by admtrz ligands, and the external copper(I) atoms are coordinated by terminal thiocyanate. The EPR spectra of 2 show the existence of localized mixed-valence copper ions. The triangle trinuclear copper cation in compound 3 has its Cu(3) triangle capped by one apical mu(3)-OH group, each edge bridged by a bridging admtrz ligand and each Cu atom coordinated by a N atom from the terminal thiocyanate, while one of the three edges is further bridged by another admtrz ligand and the opposite Cu1 atom is coordinated by a water molecule. The EPR and magnetic susceptibility of compound 3 were studied, showing antiferromagnetic behavior.

Trinuclear copper(II) complexes with bridging (N–N) diazine ligands: structural and magnetic studies

The polytopic ligands 2poap and po2p have a linear disposition of coordination pockets suitably disposed to bind metal ions in close proximity and produce linear trinuclear copper(II) complexes. The complexes [Cu3(2poap − 2H)(CH3CO2)4]·3H2O (1), [Cu3(2poap − 2H)(H2O)(DMF)3(CH3OH)2](BF4)4 (2), and [Cu3(po2p − H)2(H2O)2](ClO4)4·2H2O (3) have a linear arrangement of Cu(II) centres linked by a trans arrangement of N–N single bonds. Each metal is assigned a dx2 − y2 magnetic ground state, and the trans diazine bridging arrangement leads to strong antiferromagnetic coupling in complete agreement with previous magnetostructural correlations relating the twist of the copper magnetic planes around the N–N bond to the exchange integral.

Synthesis and Characterization of Linear Trinuclear Copper(II) Complexes

Six novel trinuclear copper(II) complexes have been synthesized and identified as {[Cu(opba)][Cu(L)]2} (CIO4)2xH2O and {[Cu(Meopba)][Cu(L)]2} (CIO4)2xH2O [obpa = o-phenylenebis(oxamato), Meopba = 4-methyl-o-phenylenebis(oxamato), L -2, 2′-bipyridyl (bpy), 1, 10-phenanthroline (phen) or 4,4′-dimethyl-2, 2′-bipyridyl (Mebpy), x=1,2]. Based on IR, elemental analyses, electronic spectra, conductivity and thermoanalyses, the complexes are proposed to have an oxamido-bridged structure consisting of three copper(II) ions in which each copper(II) ion has a square-planar environment.

A novel linear trinuclear copper(II) compound with 4-(2-pyridyl)-1,2,4-triazole as a bridging ligand

Reaction of Cu(ClO 4) 2⋅6H 2O with 4-(2-pyridyl)-1,2,4-triazole (abbreviation pytrz) resulted in the formation of the trinuclear Cu(II) complex [Cu 3(pytrz) 10(H 2O) 2](ClO 4) 6⋅7H 2O. The X-ray diffraction study shows that the central copper atom lies on an inversion center and is triply bridged to each of the external copper atoms by the pytrz ligands through the nitrogen atoms in 1,2-positions. Each external copper atom completes its octahedral surroundings with two pytrz ligands and one water molecule. Variable temperature magnetic susceptibility (77–300 K) suggests a weak antiferromagnetic interaction between neighboring copper(II) ions.

Linear trinuclear and one-dimensional copper(II) complexes containing co-bridging end-on azido and triazole ligands. Crystal structures and magnetic properties of [Cu3(atrz)2(N3)6] and [Cu(atrz)2(N3)]NO3 (atrz = 4-amino-1,2,4-triazole)

New complexes with 1,2,4-triazole and end-on azido bridging ligands, [Cu3(atrz)2(N3)6] 1 and [Cu(atrz)2(N3)]NO32 (atrz = 4-amino-1,2,4-triazole), have been prepared and structurally determined. Complex 1 has a linear trinuclear copper(II) structure with bridging bond angles Cu–N–N (atrz) [119.3(3) and 123.4(3)°], and larger Cu–N–Cu [118.7(2)°]. In 2 the copper(II) ions are linked by one end-on azido and two triazole bridges forming a cationic chain with Cu–N–N (equatorial atrz) [121.0(2) and 122.3(2)°] and Cu–N–Cu 104.05(12)°. The nearest-neighbour Cu· · ·Cu distances are 3.4496(7) A for 1 and 3.5034(6) A for 2. The copper(II) ions are strongly antiferromagnetically coupled with J = –108.8 cm–1 for 1, and weakly with J = –17.7 cm–1 for 2. The nature and the magnitude of the antiferromagnetic exchange of both complexes are discussed based on their structures.

Linear Trinuclear Copper(II) Complexes Bridged by Oximato and Azido or Hydroxo Groups

Abstract The linear trinuclear copper(II) complexes Cu3(L1)2(N3)2(NO3)2·2H2O·2CH3OH 1 and Cu3(L1)2(OH)2(ClO4)2 2 containing 3-[{2-(2-pyridinyl)ethyl}imino]-2-butanone oximato ligand (L1) were prepared; the crystal structure of 1 was determined by X-ray crystallography. Magnetic susceptibility measurements from liquid helium temperature to room temperature showed a vary strong antiferromagnetic exchange coupling between copper(II) ions(J = −266 cm−1 and −245 cm−1 for 1 and 2, respectively, H=−2JS1·S2).

Synthesis, electrochemical and magnetic properties of Cu3 complexes of a series of new compartmental trinucleating ligands H4L

A series of linear trinuclear copper(II) complexes [Cu 3 L(dmso) 5 (H 2 O)][ClO 4 ] 2 ·H 2 O {H 4 L = 2,6-bis[(5-substituted salicylidene)hydrazinocarbonyl]pyridine; L = L 1 , R = H; L = L 2 , R = Me 3 ; L = L 3 , R = Bu t ; L = L 4 , R = OMe 3 ; L = L 5 , R = Cl; L = L 6 , R = Br; dmso = dimethyl sulfoxide} have been synthesized and characterized on the basis of infrared and electronic spectra, electrochemical and variable-temperature (80–300 K) magnetic measurements. The crystal and molecular structure of [Cu 3 L 1 (dmso) 5 (H 2 O)][ClO 4 ] 2 ·H 2 O has been established by X-ray diffraction. The structure consists of a Cu II Cu II Cu II trinuclear cation, unco-ordinated perchlorate anions, and a water molecule of crystallization. Each copper ion is in a square-pyramidal environment. The compartmental ligand L 1 co-ordinates in two different modes: (i) as tridentate in the terminal compartment defined by the hydrazonic carbonyl, hydrazonic nitrogen and phenolic oxygen; (ii) tridentate in the central chamber defined by the pyridyl nitrogen and two hydrazonic nitrogens. Cryomagnetic investigations reveal a moderately strong antiferromagnetic spin exchange among adjacent copper(II) ions in each complex (J = -40 to -65 cm -1 ), showing that the compartmental ligands of the Cu II Cu II Cu II are good mediators for spin-exchange interactions. Cyclic voltammetry of complex 1 showed one oxidation wave attributed to Cu II Cu II Cu II →& -e - Cu II Cu III Cu II , a one-electron transfer reduction peak due to Cu II Cu II Cu II →& +e - Cu II Cu I Cu II and a two-electron transfer wave established as Cu II Cu I Cu II →+2e - Cu I Cu I Cu I .

Linear trinuclear copper(II) complexes derived from acyclic hexadentate schiff base ligands

New linear trinuclear copper(II) complexes, 1 and 2, derived from two acyclic hexadentate (N 4O 2) Schiff base ligands were synthesised and characterised. Each complex consisted of two ligand molecules sharing three copper(II) atoms and two anions. The X-ray crystal study of 2 revealed that the three copper(II) atoms form an exact linear arrangement having Cu(2) on the inversion centre and a Cu(1)Cu(2) distance of 3.985 Å. The central copper(II) is situated at the centre of the plane defined by an N 2O 2 square-planar coordination geometry. The coordination sphere (N 3O) of each terminal copper(II) can be described as strongly distorted tetrahedral. The cyclic voltammograms of the complexes demonstrated two quasi-reversible reductions in which one is a redox process of two one-electron steps, associated with the two terminal copper(II) ions, and the second is the electron transfer process of the central copper(II).

Structure and magnetic properties of a syn-anti carboxylate bridged linear trinuclear copper(II) complex with ferromagnetic exchange interaction

The synthesis, crystal structure and magnetic properties are reported for the trinuclear compound [Cu(H 2O) 4{Cu(HL)(H 2O)(ClO 4)} 2][ClO 4] 2·2H 2O, where HL is the monodeprotonated form of 6-methylamino-1,3-dimethyl-5-[(2′-carboxyphenyl)azo]uracil. The compound crystallizes in the triclinic system, space0 group P 1 , with cell constants a=7.824(3), b=12.278(3), c=13.705(9) Å, α=104.34(3), β=91.80(3), γ=103.37(5)° and Z=1. The structure was solved and refined to R=0.071 ( R w=0.064). The structure consists of trinuclear [Cu(H 2O) 4{Cu(HL)(H 2O)(ClO 4)} 2] 2+ cations, non-coordinated perchlorate anions and crystal water molecules, held together by a network of hydrogen bonds. The central copper is in an elongated octahedral CuO 6 chromophore and the terminal copper atoms in distorted square-pyramidal CuNO 4 chromophores. Adjacent copper atoms are linked by carboxylate groups in a syn-anti conformation. From the magnetic susceptibility measurements, the complex is found to exhibit weak ferromagnetic interaction between nearest-neighbour copper(II) ions. The magnitude and nature of the exchange coupling are discussed on the basis of the structural data.

Synthesis, crystal structure and magnetic properties of a linear trinuclear copper(II) compound with chloride and 4-amino-3,5-bis(hydroxymethyl)-1,2,4-triazole as bridging ligands

Download options Please wait... Article information DOI https://doi.org/10.1039/DT9930002163 Article type Paper Download Citation J. Chem. Soc., Dalton Trans., 1993, 2163-2167 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Synthesis, crystal structure and magnetic properties of a linear trinuclear copper(II) compound with chloride and 4-amino-3,5-bis(hydroxymethyl)-1,2,4-triazole as bridging ligands P. J. van Koningsbruggen, J. W. van Hal, R. A. G. de Graaff, J. G. Haasnoot and J. Reedijk, J. Chem. Soc., Dalton Trans., 1993, 2163 DOI: 10.1039/DT9930002163 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author Petra J. van Koningsbruggen Jaap W. van Hal Rudolf A. G. de Graaff Jaap G. Haasnoot Jan Reedijk

Structure of the linear trinuclear copper complex, dichlorotetrakis-(di-2-pyridylamido)tricopper

The synthesis and X-ray crystal structure of a nitrogen-bridged linear trinuclear copper complex [Cu3(dpa)4Cl2]{dpa = di-2-pyridylamido, [(C5H4)2N]–}, with extremely short Cu–Cu bond distances [2.4712(4)A] and tridentate dipyridylamido ligands in a novel syn-syn conformation are reported.

Linear trinuclear copper(II) complex with aminoalcohol and fluoroacetic acid. The crystal and molecular structures of Bis[μ-(2-diethylaminoethanolato- N,μ- O)]-bis[μ-fluoroacetato- O, O′]-bis(fluoroacetato)-bis(ethanol)tricopper(II)

The crystal and molecular structures of the linear trinuclear copper(II) complex with 2-diethylaminoethanol and fluoroacetic acid were determined by three-dimensional X-ray crystallography. Bis[μ-(2- diethylaminoethanolato- N,μ- O)]-bis[μ-fluoroacetato- O, O′]-bis(fluoroacetato)-bis(ethanol)tricopper(II) crystallizes in the triclinic space group P 1 with a = 7.963(6), b = 8.443(7), c = 13.553(6) Å, α = 76.16(5), β = 81.82(5), γ = 87.62(6)°, Z = 1. The structure was solved by direct methods and refined to the R value 0.050 using 2738 independent reflections. Like the F(2) atom, some of the C atoms of the aminoethanolato ligands are disordered with one or more rotational orientations. The three Cu(II) ions are in linear arrangement bridged by one bidentate carboxylate O atom and one 2-diethylaminoethanolato O atom. The Cu(1) atom is in 4 + 1 and the Cu(2) atom in 4 + 2 environment, and the Cu(1)Cu(2) distance is 3.126(1) Å. A 2-diethylaminoethanolato O atom, two fluoroacetate O atoms and an amino N atom form a distorted square-plane around the Cu(I) atom with Cu(1)O bonds of 1.903(4)–1.966(4) Å and a Cu(1)N bond of 2.030(4) Å; the apical site is occupied by an ethanolato O atom and the Cu(1) O(6) distance is 2.623(7) Å. The square-plane of the central Cu(2), which lies on the inversion centre, consists of two 2-diethylaminoethanolato O atoms and two carboxylato O atoms with Cu(2)O bonds of 1.946(3) and 1.954(4) Å, respectively. The apical sites are occupied by ethanolato O atoms with a Cu(2)O(6) distance of 2.525(5) Å.

Synthesis and Structure of Completely Spin-coupled Trinuclear Copper(II) Complex, [Cu(dmg)2{Cu(bipy)(CH3OH)}2](NO3)2, Bridged by Bis(dimethylglyoximato)cuprate(II) Dianion

Abstract A linear trinuclear copper(II) complex [Cu(dmg)2{Cu(bipy)(CH3OH)}2](NO3)2 in which bis(dimethylglyoximato)cuprate(II) dianion [Cu(dmg)2]2− bridges two copper(II) ions through its deprotonated oxime oxygens has been synthesized and structurally characterized. Magnetic studies in the 80–300 K range revealed complete spin-coupling at room temperature (μeff: 1.85 μB/3Cu).