Mononuclear and binuclear copper(II) complexes of some polyfunctional pyridyl phthalazines

1983 ◽  
Vol 61 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Graham Bullock ◽  
Frederick W. Hartstock ◽  
Laurence K. Thompson
Keyword(s):  
Magnetic Moments ◽  
Coupled Systems ◽  
Binuclear Complexes ◽  
Antiferromagnetic Exchange ◽  
Binuclear Copper ◽  
Copper Salts ◽  
Mononuclear Complexes ◽  
Acidic Conditions ◽  
Binucleating Ligands ◽  
Protonated Ligand

Mononuclear and binuclear copper(II) complexes of the potentially tetradentate binucleating ligands 1,4-di(3′-methyl-2′-pyridyl)aminophthalazine (PAP3Me) and 1,4-di(5′-methyl-2′-pyridyl)aminophthalazine (PAP5Me) are reported. In the case of the ligand 1,4-di(4′,6′-dimethyl-2′-pyridyl)aminophthalazine (PAP46DiMe) only binuclear derivatives were obtained. The mononuclear complexes, involving protonated ligand, result from the sensitivity of these ligands to mildly acidic conditions in aqueous solutions of certain copper salts. Binuclear, neutral ligand, complexes are also formed when the pH increases. Hydroxy bridged binuclear structures exist in all the binuclear complexes described with the exception of one acetate bridged derivative. Sub normal magnetic moments are observed for all the binuclear complexes (< 1.74 BM) indicating spin coupled systems with very low values (< 0.88 BM) for binuclear complexes of PAP46DiMe, indicating the possibility of strong antiferromagnetic exchange between the metal centres.

Synthesis and Reactivity of Copper(II) Complexes with New Binucleating Ligands Derived from 16-or 20-Membered N4-Macrocycles

1990 ◽  
Vol 45 (1) ◽  
pp. 39-44 ◽  
Author(s):  
Yuzo Nishida
Keyword(s):  
Catalytic Activity ◽  
Metal Ions ◽  
Binuclear Complex ◽  
Esr Spectra ◽  
Cyclic Voltammograms ◽  
Binuclear Complexes ◽  
Binuclear Copper ◽  
Coordination Sites ◽  
Trinuclear Complexes ◽  
Binucleating Ligands

Abstract New binucleating ligands, (L1) N ,N′,N″,N‴-tetrakis(2-benzimidazolylmethyl)-1,4,9,12-tetra-azacyclohexadecane, and (L2) N ,N′,N″,N‴-tetrakis(2-benzimidazolylmethyl)-1,4,11,14-tetra-azacycloeicosane were prepared. From the reaction mixture of copper(II) salt and the ligand, new binuclear copper(II) complexes, Cu2(L1) (NO3)4 (1), Cu2(L2)(NO3)4 (2), Cu2(L2)Br4 (3), and trinuclear complexes, Cu3(L1)Cl6 (4), and Cu3(L2)Cl6 (5) were obtained. Cyclic voltammograms revealed that the trinuclear complexes 4 and 5 are composed with the binuclear complex (1 or 2) and [CuCl4]2-. The interaction between two metal ions in the binuclear complexes are confirmed on the basis of the ESR spectra. These binuclear complexes exhibit higher catalytic activity for the oxidation of TMPD by O2 molecule than those of structurally rigid binuclear copper(II) complexes and of flexible binuclear complexes in which two copper(II) coordination sites are linked by a single polyatomic chain.

Interaction between Binuclear Copper(I) Complexes and the Dioxygen Molecule Investigated by Electrochemical Methods

1992 ◽  
Vol 47 (1) ◽  
pp. 109-114 ◽  
Author(s):  
Yuzo Nishida ◽  
Izumi Watanabe ◽  
Kei Unoura
Keyword(s):  
Cyclic Voltammetry ◽  
Thin Layer ◽  
Electrochemical Reduction ◽  
High Reactivity ◽  
Electrochemical Methods ◽  
Tridentate Ligand ◽  
Cyclic Voltammograms ◽  
Binuclear Copper ◽  
Alkyl Chains ◽  
Binucleating Ligands

The cyclic voltammograms of some binuclear copper(II) compounds with binucleating ligands where two molecules of tridentate ligand, N, N -bis(benzimidazol-2-ylmethyl)amine are linked by several alkyl chains, were measured under both argon and dioxygen. The results demonstrate that the binuclear copper(I) species produced by electrochemical reduction exhibit high reactivity towards dioxygen, while the reaction of the corresponding mononuclear species with oxygen is very slow. Thin-layer coulometry ([binuclear copper(I)]/[O2] = 0.47 - 10.6) and thin-layer cyclic voltammetry ([binuclear copper(I)]/[O2] = 4.3 - 10.6 ) revealed that two molecules of the binuclear copper(I) species react with one molecule of dioxygen.

Binuclear copper(II) complexes of the tetradentate ligand 1,4-di(2′-pyridyl)aminophthalazine: some novel five-coordinate derivatives

1969 ◽  
Vol 47 (22) ◽  
pp. 4141-4152 ◽  
Author(s):  
L. K. Thompson ◽  
V. T. Chacko ◽  
J. A. Elvidge ◽  
A. B. P. Lever ◽  
R. V. Parish
Keyword(s):  
Room Temperature ◽  
Principal Series ◽  
Magnetic Data ◽  
Binuclear Copper ◽  
Neutral Form ◽  
Deprotonated Form ◽  
Copper Salts ◽  
X Ray ◽  
Anionic Ligand ◽  
Aromatic Carboxylate

Reaction of the title ligand (L) with copper salts leads to the formation of three principal series of compounds, LCu2X3(OH)•H2O (X = Cl, Br), LCu2(RCO2)3, and LCu2(RCO2)4, where RCO2 represents various aliphatic and aromatic carboxylate species. Magnetic data, electronic spectroscopic data both at room temperature and at −196 °C, infrared spectra, and microanalytical data are correlated to reveal that these complexes contain a binuclear copper-copper system in which the copper atoms are 5-coordinate and square pyramidal. Brief details are presented of an X-ray structural analysis of the chloride complex confirming the structure proposed.The ligand forms complexes both in its neutral form and in an anionic deprotonated form. The ultraviolet spectra of the complexes distinguish these modes of bonding. The electronic spectra are discussed in terms of the 5-coordinate square pyramidal copper chromophore deemed to be present. In the complex L2Cu, the copper atom has a trigonally distorted 6-coordinate environment with tridentate anionic ligand.

Structure and magnetism in a hydroxy bridged binuclear copper(II) system with a "tunable" binuclear centre

1983 ◽  
Vol 61 (3) ◽  
pp. 579-583 ◽  
Author(s):  
Laurence K. Thompson
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
Coordination Geometry ◽  
Antiferromagnetic Exchange ◽  
X Ray Diffraction ◽  
Binuclear Copper ◽  
Space Group ◽  
X Ray ◽  
Oxygen Bridge ◽  
Copper Coordination

The molecular structure of [Cu2(PAP)(OH)(IO3)3]•4H2O (PAP = 1,4-di(2′-pyridyl)aminophthalazine) has been determined by single crystal X-ray diffraction. [Cu2(PAP)(OH)(IO3)3]•4H2O belongs to the space group P21/c with a = 7.266(1), b = 15.269(1), c = 25.870(1) Å, β = 96.40(I)°, V = 2852.2 Å3, Z = 4. The copper coordination geometry lies between a square pyramid and a trigonal bipyramid and the two copper(II) centres are bridged by three groups: N2 (phthalazine), hydroxide, and bidentate iodate, in a structure which is analogous to that reported for [Cu2(PAP)(OH)Cl3]•1.5H2O. Replacing the chlorine bridge by iodate has the effect of forcing the two metal centres further apart, thus creating a larger Cu—O—Cu bridge angle. This increase in oxygen bridge angle (101° to 114°) is also reflected in the enhanced antiferromagnetic exchange (−2J(Cl) = 201 cm−1, −2J(IO3) = 335 cm−1). Other groups of varying size (e.g. Br, NO3, SO4) can act as bridges between the two copper centres in systems of this sort with the resultant variation in copper–copper separation and oxygen bridge angle.

Copper complexes of polyfunctional phthalazines. Mononuclear and polynuclear derivatives

1982 ◽  
Vol 60 (20) ◽  
pp. 2583-2593 ◽  
Author(s):  
Dorothy V. Bautista ◽  
John C. Dewan ◽  
Laurence K. Thompson
Keyword(s):  
Copper Complexes ◽  
Magnetic Moments ◽  
Magnetic Data ◽  
Binuclear Complexes ◽  
Tetradentate Ligands ◽  
Binuclear Structure ◽  
Neutral Ligands ◽  
Hydroxide Bridge ◽  
Anionic Groups ◽  
Protonated Complexes

Mononuclear, binuclear, and trinuclear copper(II) complexes of the tetradentate ligands 1,4-di(2′-pyridyl) aminophthalazine (PAP) and 1,4-di(4′-methyl-2′-pyridyl) aminophthalazine (PAP4Me) and binuclear complexes of the tetradentate ligand 1,4-di(6′-methyl-2′-pyridyl) aminophthalazine (PAP6Me) are reported. In a series of binuclear carboxylate derivatives carboxylate bridges exist between copper centres in all cases and in some cases oxygen bridges (hydroxide or methoxide) are indicated. In all other polynuclear derivatives hydroxide bridges are anticipated on the basis of analytical, spectral, and magnetic data. The ligands exist as anionic groups in some binuclear carboxylate derivatives while in the other polynuclear systems neutral ligands are found. In reactions in aqueous solution protonated mononuclear derivatives are obtained for both PAP and PAP4Me in cases where solutions of the metal salts are inherently acidic, followed by polynuclear, neutral ligand complexes which form when the pH increases. Mononuclear protonated complexes are not obtained with PAP6Me, where steric factors may prevent the formation of such derivatives. Low magnetic moments (1.1–1.5 BM) are observed for most hydroxy bridged complexes while even lower values ( < 0.70 BM ) are observed for two binuclear complexes of PAP6Me, indicating the possibility of strong antiferromagnetic exchange between metal centres. A preliminary X-ray investigation of the complex [Cu2(PAP4Me)(OH)(NO3)2(H2O)2]NO3 indicates a triple bridged binuclear structure including a bidentate nitrate bridge and a hydroxide bridge with an oxygen bridge angle of 115.2°.

scholarly journals Synthesis and Characterisation of New Symmetrical Binucleating Ligands and Their Binuclear Copper(II) Complexes

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
K. Jothivenkatachalam ◽  
S. Chandra Mohan
Keyword(s):  
Electron Transfer ◽  
Exchange Interaction ◽  
Variable Temperature ◽  
Esr Spectra ◽  
Single Step ◽  
Binuclear Copper ◽  
Magnetic Studies ◽  
Weak Exchange ◽  
Broad Signal ◽  
Binucleating Ligands

New symmetrical binucleating ligands N,N-bis[2-hydroxy-5-methyl-3-(4-methyl-piperazinomethyl)benzyl]-alkylamines L1 and L2 and their copper(II) complexes [Cu2L(X)2]·2H2O, where X = CH3COO−, C6H5COO−, Cl−, and ClO4-, were prepared and characterised. All the complexes undergo quasi-reversible reduction at negative potential (E = −0.48 to −1.02 V). The acetate and benzoate complexes undergo a two-step single electron transfer at –0.48 to –0.60 V and −0.9 to −1.02 V. The chloro and perchlorate complexes undergo a single step two-electron transfer at −0.55 to −0.75 V. Variable temperature magnetic studies show the presence of weak exchange interaction for acetate (−2 J around 25 to 40 cm−1) and benzoate (−2 J around 45 to 55 cm−1) bridged complexes and no exchange interaction is found for chloro and perchlorate complexes. ESR spectra of chloro and perchlorate complexes are like mononuclear copper(II) complexes with hyperfine splitting (A = 165 ± 5, g∥ = 2.17–2.23, and g⊥ = 2.05–2.10). The ESR spectra of acetate and benzoate complexes are like binuclear copper(II) complexes with broad signal (g = 2.2).

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