Complex Formation Between Imidazole and Nickel(II) Salts

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.

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Synthesis and structure of 4-methylpyridine complexes of cobalt(II) and nickel(II) hexafluorophosphate and hexafluoroarsenate

Canadian Journal of Chemistry ◽

10.1139/v78-165 ◽

1978 ◽

Vol 56 (7) ◽

pp. 985-991 ◽

Cited By ~ 9

Author(s):

Raymond M. Morrison ◽

Robert C. Thompson

Keyword(s):

Magnetic Properties ◽

Field Strength ◽

Single Crystal ◽

Infrared Spectra ◽

Electronic Spectra ◽

Preliminary Report ◽

Ligand Field ◽

X Ray Diffraction ◽

X Ray ◽

Square Planar

The complexes M(4mepy)4A2 and M(H2O)2(4mepy)8A2 (where M is Ni or Co and A is PF6 or AsF6) have been prepared and their electronic spectra and magnetic properties studied. A preliminary report is made of single crystal X-ray diffraction studies on Ni(H2O)2(4mepy)8(PF6)2, Co(H2O)2(4mepy)8(PF6)2, and Co(4mepy)4(PF6)2. All of the complexes have structures involving complex cations and non-coordinated anions, consistent with extremely weak ligating abilities for both PF6− and AsF6−. Cations identified and characterized are the squashed tetrahedral [Co(4mepy)4]2+ ion, the square planar [Ni(4mepy)4]2+ ion, and the tetragonal [Co(4mepy)4((4mepy)2H2O)2]2+and [Ni(4mepy)4((4mepy)2H2O)2]2+ ions. The ligand field strength of 4-methylpyridine is found to be indistinguishable from that of pyridine in these complexes. Infrared spectra are reported and infrared criteria for establishing the presence of non-coordinated anions in PF6− and AsF6− complexes are suggested.

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Complexes of substituted benzothiazoles 4. Nickel(II) complexes of the bidentate benzothiazoles 1,2-bis(2-benzothiazolyl)benzene and 1,2-bis(2-benzothiazolyl)ethane

Canadian Journal of Chemistry ◽

10.1139/v82-075 ◽

1982 ◽

Vol 60 (4) ◽

pp. 514-520 ◽

Cited By ~ 8

Author(s):

Laurence Kenneth Thompson ◽

John Charles Thomas Rendell ◽

George Charles Wellon

Keyword(s):

Coordination Chemistry ◽

Infrared Spectra ◽

Nickel Complexes ◽

Magnetic Data ◽

Octahedral Complex ◽

Ligand Field ◽

Tetrahedral Coordination ◽

Ethylene Bridge ◽

X Ray ◽

Square Planar

The nickel coordination chemistry of two potentially bidentate bis-benzothiazole ligands is compared. 1,2-Bis(2-benzothiazolyl)-benzene (OBT), which has an o-phenylene bridge, forms square planar derivatives with NiX2 (X = I, ClO4, BF4), octahedral derivatives with NiX2 (X = NCS, NO3), and five-coordinate derivatives with NiX2 (X = CI, Br). 1,2-Bis(2-benzothiazolyl)ethane (BBTE), which has an ethylene bridge, forms tetrahedral derivatives with NiX2 (X = CI, Br, I) and an octahedral complex with Ni(NO3)2. Although both ligands are capable of tetrahedral coordination about a cobalt centre, the apparent preference of tetrahedral coordination with nickel complexes of BBTE seems unusual. The only difference between the two ligands lies in the bridging group between the benzothiazole rings. Structural assignments are supported by ligand field and infrared spectra, magnetic data, and an X-ray structure of the complex [Ni(BBTE)Br2], which has been shown to have a distorted tetrahedral stereochemistry.

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The Coordination Chemistry of Phosphoryl Compounds Containing the — N(CH3)2 Group, Part VIII

Zeitschrift für Naturforschung B ◽

10.1515/znb-1972-0706 ◽

1972 ◽

Vol 27 (7) ◽

pp. 759-763 ◽

Cited By ~ 11

Author(s):

M. W. G. De Bolster ◽

W. L. Groeneveld

Keyword(s):

Coordination Chemistry ◽

General Formula ◽

Ligand Field ◽

Chemical Analyses ◽

X Ray ◽

Physical Measurements ◽

Ligand Field Spectra ◽

Chloride Adduct ◽

Ligand Field Parameters ◽

Group Part

A number of new solvates and adducts containing bisphenyldimethylaminophosphine oxide is reported. The solvates have the general formula M[(C6H5)2P(O)N(CH3)2]42+(anion-)2, in which M = Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn and Cd, and the anions are ClO4- and BF4-. The adducts have the general formula M[(C6H5)2P(O)N(CH3)2]2Cl2, where M stands for the same series of metals.The compounds are characterized and identified by chemical analyses and physical measurements.Ligand-field and vibrational spectra have been investigated; values for the ligand-field parameters are reported. It is concluded that coordination takes place via the oxygen atom of the ligand.X-ray powder patterns were used in combination with ligand-field spectra to deduce the coordination around the metal ions.The interesting behaviour of the nickel (II) chloride adduct upon heating is discussed and it is shown that both a square pyramidal and a tetrahedral modification exists.

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Preparation, and complexes with nickel(II) and copper(II), of a diazepane amine alcohol. The structure of [4,4-dimethyl-7-(5,5,7-trimethyl-1,4-diazepan-1-yl)-5-azaheptan-2-ol]nickel(II) perchlorate

Australian Journal of Chemistry ◽

10.1071/ch9831341 ◽

1983 ◽

Vol 36 (7) ◽

pp. 1341 ◽

Cited By ~ 4

Author(s):

KR Morgan ◽

GJ Gainsford ◽

NF Curtis

Keyword(s):

Ground State ◽

Coordination Compounds ◽

Major Product ◽

Boat Conformation ◽

Singlet Ground State ◽

X Ray Diffraction ◽

X Ray ◽

Oxygen Donor ◽

Square Planar ◽

Coordination Plane

Reduction of 4,4,12,12-tetramethyl-5,8,11-triazapentadecane-2,14-dione diperchlorate by sodium borohydride yields as the major product one isomer of 4,4-dimethyl-7-(5,5,7-trimethyl-1,2-diazepam 1-yl)-5-azaheptan-2-ol, pyaz. The coordination compounds [M(pyaz)] (ClO4), and [Ni(pyaz)(NCS)] CNS (M = NiII, CuII) were prepared, the latter being assigned five-coordinate structures. The structure of singlet ground state [Ni(pyaz)] (ClO4)2 was determined by X-ray diffraction [space group P212121, Z 4, a 1450.8(2), b 1522.2(1), c 1048.5(1) pm, R 0.0675, Rw 0.0768 for 2461 reflections]. The compound has a square-planar coordination arrangement, with the three nitrogen and the oxygen donor atoms of the pyaz ligand approximately coplanar [Ni-O 190.0(6) pm; Ni-N 192.8(6), 189.2(6), 189.2(6) pm in sequence N(5) of chain, N(l), N(4) of diazepane]. The diazepane ring adopts a boat conformation. One side of the nickel(II) coordination plane is sterically crowded by the presence of two axial methyl substituents. The ligand has two non-equivalent chiral centres (C(14) of the diazepane ring and C(2) of the amine alcohol chain), both present in the R configuration in the crystal studied. The three nitrogen atoms, which became chiral centres upon coordination, are present in the S configuration for two diazepane nitrogen atoms and in the R configuration for the 5-aza chain nitrogen.

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

Australian Journal of Chemistry ◽

10.1071/ch9800737 ◽

1980 ◽

Vol 33 (4) ◽

pp. 737 ◽

Cited By ~ 58

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.

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

Inorganic Chemistry ◽

10.1021/ic50217a033 ◽

1981 ◽

Vol 20 (3) ◽

pp. 796-800 ◽

Cited By ~ 36

Author(s):

L. G. Vanquickenborne ◽

A. Ceulemans

Keyword(s):

Ligand Field ◽

Square Planar ◽

Ligand Field Spectra

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Coordination compounds of norbornadiene with silver tetrafluoroborate

Canadian Journal of Chemistry ◽

10.1139/v68-022 ◽

1968 ◽

Vol 46 (2) ◽

pp. 117-124 ◽

Cited By ~ 4

Author(s):

Harold W. Quinn

Keyword(s):

Aqueous Solution ◽

Aqueous Solutions ◽

Infrared Spectra ◽

Coordination Compounds ◽

X Ray Diffraction ◽

X Ray ◽

Hydrated Complexes ◽

Crystalline Complexes Of

Crystalline complexes of norbornadiene with silver tetrafluoroborate have been obtained both from anhydrous and aqueous solution. While both solutions yield complexes of stoichiometry AgBF4•C7H8 and 2AgBF4•3C7H8, those from the aqueous solutions also contain water of crystallization. The infrared spectra show that norbornadiene is similarly complexed in both the anhydrous and hydrated complexes but that the coordination in the 1:1 complex is different from that in the 2:3 complex. The anhydrous and hydrated 1:1 complexes have the same X-ray diffraction powder patterns while those of 2:3 complexes are different.

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Copper(II) complexes of o-hydroxyarylcarbonyl compounds

Australian Journal of Chemistry ◽

10.1071/ch9680617 ◽

1968 ◽

Vol 21 (3) ◽

pp. 617 ◽

Cited By ~ 36

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.

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