Copper(II) complexes of o-hydroxyarylcarbonyl compounds

1968 ◽  
Vol 21 (3) ◽  
pp. 617 ◽  
Author(s):  
DP Graddon ◽  
GM Mockler
Keyword(s):  
Solid State ◽  
Chelate Ring ◽  
Magnetic Moments ◽  
Equilibrium Constants ◽  
Ligand Field ◽  
Infrared Band ◽  
Planar Structures ◽  
Square Planar ◽  
Inductive Effects ◽  
Ligand Field Spectra

A series of copper(11) complexes has been prepared of the type CuL2Bn, where L is an o-hydroxy-aryl-, or naphthyl-, aldehyde, ketone, or ester, B is water or 4-methylpyridine, and n = 0, 1, or 2. All these complexes have a strong infrared band in the region 1600-1660 cm-l, showing that the oxygen atoms in the chelate ring are non-equivalent ; their magnetic moments fall in the range usual for copper(11) compounds. Equilibrium constants determined for the addition of one molecule of 4-methylpyridine to the anhydrous compounds in chloroform solutions fall in the range 0.5 < k < 40 and are comparable to the constant for the addition of 4-methylpyridine to bis(acetylacetonato)copper(11) (b 2.7). Increased stability of the adducts can be associated with the inductive effects of ligand substituents. Ligand field spectra in the solid state and in solution closely resemble those of corresponding bis(acetylaoetonato)copper(11) complexes and provide evidence for square-planar structures of the anhydrous complexes and square-pyramidal structures of the 1 : 1 adducts with 4-methylpyridine or water. No evidence is available for the structures of 1 : 2 adduots which may be formed in solutions in 4-methylpyridine; these solutions are unstable, but the nature of the slow reactions which occur in these solutions is not known.

Cobalt(II), nickel(II) and copper(II) complexes of some 2'-hydroxychalcones

1980 ◽  
Vol 33 (4) ◽  
pp. 737 ◽  
Author(s):  
M Palaniandavar ◽  
C Natarajan
Keyword(s):  
Infrared Spectra ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Phenyl Group ◽  
Ligand Field ◽  
Square Planar ◽  
Spin Pairing ◽  
Square Configuration ◽  
Electron Sink ◽  
Octahedral Configuration

Metal(II) bis-chelates of the type ML2 [M = CoII, NiII, CuII; L = 2'- hydroxy-5'-X-chalcone where X = H, CH3, Cl] have been prepared and studied. Structures have been assessed by the measurement of magnetic moments, ligand field and infrared spectra and thermal properties. These chelates possess low-spin trans-square-planar configuration and show resistance to adduct formation in contrast to metal(II) chelates of β-diketones, salicylaldehyde, o-hydroxyaryl ketones and esters and o-hydroxy-crotonophenones, which have high-spin octahedral configuration. Extensive conjugation lowers the energy of the π3* orbital which enters into a very strong dπ-π3* interaction leading to spin-pairing. ��� Infrared spectra indicate that the carbonyl group is perturbed only slightly by coordination to metal. A change in metal ion affects v(C=O), v(M-O) and other vibrations and the order of stability, namely, Co ≈ Ni < Cu, inferred from these vibrations is as expected for the low-spin square configuration of the chelates. Introduction of substituents (5'-X) alters only v(M-O) significantly and the order of stability, namely, Cl > CH3 > H, derived from v(M-O) is consistent with Taft's resonance polar parameters of the substituents. All these observations are explained by the electron sink property of the phenyl group.

Ligand field spectra of square-planar platinum(II) and palladium(II) complexes

1981 ◽  
Vol 20 (3) ◽  
pp. 796-800 ◽  
Author(s):  
L. G. Vanquickenborne ◽  
A. Ceulemans
Keyword(s):  
Ligand Field ◽  
Square Planar ◽  
Ligand Field Spectra

Fluorinated Alkoxides. Part VIII. Mixed Ligand Complexes of Perfluoropinacol with Ni2+, Pd2+, Pt2+ and Cu2+. Solvation Equilibria between 4- and 5-coordinate Ni2+

1975 ◽  
Vol 53 (6) ◽  
pp. 809-816 ◽  
Author(s):  
W. Stafford Cripps ◽  
Christopher J. Willis
Keyword(s):  
Metal Ion ◽  
Nickel Complexes ◽  
Mixed Ligand ◽  
Ligand Field ◽  
Electronic Effects ◽  
Unusual Behavior ◽  
Planar Structures ◽  
Square Planar ◽  
Phosphorus Containing ◽  
Fluorinated Alkoxides

Perfluoropinacol, (CF3)2C(OH)C(OH)(CF3)2, ionizes by loss of two protons, and the resulting dinegative ion (PFP2−) chelates to Ni2+, Pd2+, Pt2+, and Cu2+. A variety of stable neutral complexes may be isolated if the tetracoordination of the metal ion is completed with two monodentate or one bidentate nitrogen- or phosphorus-containing ligands; square-planar structures are invariably found. The structures of these complexes are contrasted with those of analogous halides, and it is concluded that electronic effects are predominant in determining them, although steric influences may sometimes be important. The ligand field strength of the perfluoropinacolato ion is approximately equal to that of the thiocyanate ion.The nickel complexes Ni(PFP)22− and (PFP)Ni(RNHCH2CH2NHR) react with donor solvents (water, methanol, pyridine, etc.) to give equilibria between four- and five-coordinate solvated species; six-coordinate species are not observed. This unusual behavior is attributed to the steric hindrance imposed by the bulk of the PFP2− ligand.

Copper(II) complexes with 1-phenyl-4,6-dimethylpyrimidine-2-thione. Chemical, spectroscopic, magnetic, conductivity and polarographic studies

1990 ◽  
Vol 55 (9) ◽  
pp. 2199-2215 ◽  
Author(s):  
Raffaele Battistuzzi ◽  
Marco Borsari
Keyword(s):  
Room Temperature ◽  
Copper Ions ◽  
Magnetic Moments ◽  
Thermal Analyses ◽  
Ligand Field ◽  
L System ◽  
Counter Ions ◽  
Ligand Field Spectra ◽  
Ir Bands ◽  
Magnetic Conductivity

New copper(II) complexes of general composition: CuLX2.nH2O (X = Cl-, n = 0.25; X = NO3-, n = 0.5), Cu2L3Cl4.2H2O, CuL2X2.H2O (X = ClO4-, BF4- and NO3-) and Cu2L7X4 (X = ClO4-, BF4- and NO3-), where L = 1-phenyl-4,6-dimethylpyrimidine-2-thione, have been isolated. Chemical and thermal analyses, conductivity, magnetic susceptibility, infrared and ligand field spectroscopic data and, for the perchlorate complexes also polarographic studies, are reported. Diagnostic IR bands frequencies of counter-ions, χ(Cu-X) modes and ligand field spectra for the mono-and bis-ligand compounds, having an equatorial [CuNSCl2], [CuNSO2] and [CuN2S2] microsymmetry, indicate a coordinating character of some anions, suggesting an elongated octahedral geometry for these complexes. For the [Cu2L7]X4 (X = ClO4-, BF4- and NO3-) complexes, which exhibit at room temperature subnormal magnetic moments, a polynuclear structure with the copper(II) in a roughly square-pyramidal environment, is proposed. Polarographic data for the perchlorate complexes and for the Cu(ClO4)2-L system at various ligand concentrations, have shown that in DMF solution the prevailing species are [CuL2]2+, [CuL3]2+ and [Cu2L7]4+ confirming the oxidation state II for the copper ions in the [Cu2L7]X4 complexes.

scholarly journals Complex Formation Between Imidazole and Nickel(II) Salts

1974 ◽  
Vol 29 (7-8) ◽  
pp. 527-531 ◽  
Author(s):  
J. C. Jansen ◽  
J. Reedijk
Keyword(s):  
Complex Formation ◽  
Infrared Spectra ◽  
Coordination Compounds ◽  
Tetragonal Symmetry ◽  
Ligand Field ◽  
X Ray ◽  
Square Planar ◽  
Ligand Field Spectra ◽  
Crystal Field Parameters ◽  
Imidazole Compounds

Coordination compounds of formula Ni(Iz)nX2(H2O)m, in which Iz=imidazole, n = 1, 2, 4, 6, m = 0-4, and X = Cl-, Br-, I- and NCS-, are described. The anhydrous compounds are prepared from ethanolic solutions of Iz and nickel(II) salts in stoichiometric amounts in the presence of the dehydrating agent triethylorthoformate. Without this dehydrating agent hydrates are isolated for n = 2,4 and 6 with X = Cl, Br.The compounds were identified by means of infrared spectra (4000-25 cm-1), ligand-field spectra (35000-4000 cm-1) and X-ray powder diagrams. Compounds of formula [Ni(Iz)6]X2 all contain octahedrally coordinated Ni2+, for which the spectrochemical parameters were obtained. Tetragonal Ni2+ ions occur in [Ni(Iz)4X2] in which X = Cl and NCS, and in [Ni(Iz)4(H2O)2]X2 in which X = Cl and Br. These compounds are paramagnetic and the crystal-field parameters for tetragonal symmetry have been calculated. In [Ni(Iz)4]X2 with X = I and Br, the Ni2+ ions are square-planar coordinated with anions in the second coordination sphere, resulting in orange-coloured diamagnetic compounds.Anion-bridged distorted octahedrally coordinated Ni2+ ions probably occur in the compounds of formula Ni(Iz)2X2, in which Iz takes the axial positions. Similar structures are suggested for the mono-imidazole compounds, NiIzX2.

Some complexes of Fe(II) with thiourea ligands

1967 ◽  
Vol 45 (10) ◽  
pp. 1135-1142 ◽  
Author(s):  
R. A. Bailey ◽  
Terry Roy Peterson
Keyword(s):  
Infrared Spectra ◽  
Sulfur Atom ◽  
Magnetic Moments ◽  
The Other ◽  
Ligand Field ◽  
Thiocyanate Ion ◽  
Ligand Field Spectra

Fe(thiourea)2(SCN)2, Fe(thiourea)4Cl2, and FeL2Cl2 (where L = methylthiourea, 1,3-dimethylthiourea, and 1,3-diethylthiourea) have been prepared and characterized. Magnetic moments and ligand field spectra indicate that all are octahedral. Infrared spectra show that the thiourea and methylthiourea ligands coordinate through the sulfur atom; the other two ligands are probably sulfur bonded also. The thiocyanate ion is coordinated through the nitrogen.

Tertiary phosphine complexes of the cobalt(III) NN′-ethylenebis(salicylideneiminato) and bisdimethylglyoximato systems

1976 ◽  
Vol 54 (12) ◽  
pp. 1875-1883 ◽  
Author(s):  
C. W. Smith ◽  
G. W. Van Loon ◽  
M. C. Baird
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Equilibrium Constants ◽  
Ligand Field ◽  
Tertiary Phosphine ◽  
H Nmr ◽  
Phosphine Complexes ◽  
Salen Complexes ◽  
Inductive Effects ◽  
Ligand Field Parameters

Complexes of the types [CosalenPR3]X, [Cosalen(PR3)2]X, [Co(DH)2PPh3X], and [Co(DH)2(PR3)2]ClO4, many of them new, have been prepared and characterized with respect to 1H nmr spectra, ligand field parameters, and equilibrium constants for the formation of the 2:1 salen complexes. 1H chemical shifts appear to be dominated by anisotropic rather than inductive effects, while the relative tertiary phosphine ligand field strengths appear to correlate with the steric requirements of the phosphines as well as their expected σ donor strengths. Ease of formation of the 2:1 salen complexes is determined largely by steric effects, as are trans effects in the DH systems.

The structure of [Cu(bipy)3][Cu(bipy)(ala)(ClO4)2]ClO4 � a Compound with Two Different Coordination Modes in the same Complex

2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Mircea Braban ◽  
Ionel Haiduc
Keyword(s):  
Solid State ◽  
Chelate Ring ◽  
Octahedral Complex ◽  
State Structure ◽  
Complex Species ◽  
Solid State Structure ◽  
Coordination Modes ◽  
Coordination Center ◽  
Self Assembled ◽  
Chelate Rings

The paper describes the solid state structure of a compound of composition [Cu(bipy)3][Cu(bipy)(ala) (ClO4)2]ClO4, in which both the cation and anion are octahedral complex species with copper(II) as coordination center. The cation contains three chelate rings formed by bipy; the anion contains in the quatorial plane a CuONC2 chelate ring formed by the alaninato ligand and a CuN2C2 chelate ring formed by bipy, with two monodentate perchorato ligands in axial positions completing the six-coordination. In the crystal p-p stackings lead to a supramolecular self-assembled structure.

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