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NiII Complex (niii + complex)

Distribution by Scientific Domains
Chemistry93%
Distribution within Chemistry
Crystallography21%

Selected Abstracts

A Terephthalato-Bridged NiII Complex Capped with a Nonchelating Ligand Displays a Three-Dimensional Supramolecular Network Constructed by Coordination and Multi-Intermolecular Forces

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2005
Chang Seop Hong
Abstract A new tp-bridged complex [Ni(pyrazole)4(tp)]n (1; tp = terephthalate) coordinated with a nonchelating pyrazole ligand has been synthesized and characterized using X-ray structure determination and magnetic studies. The crystal structure reveals that the capping ligand functions as a source of hydrogen bonding and intermolecular contacts, such as ,,, and CH,, interactions, that result in a three-dimensional supramolecular assembly. Weak antiferromagnetic couplings are transmitted between NiII centers through the tp linkage. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Water-Soluble Sal2en- and Reduced Sal2en-Type Ligands: Study of Their CuII and NiII Complexes in the Solid State and in Solution

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2006
Isabel Correia
Abstract The CuII and NiII complexes of the Schiff base pyr2en [N,N, -ethylenebis(pyridoxyliminato)] and reduced Schiff bases Rpyr2en [N,N, -ethylenebis(pyridoxylaminato)] and R(SO3,sal)2en (SO3,sal = salicylaldehyde-5-sulfonate) were prepared and characterized by elemental analysis, IR, UV/Vis, and EPR spectroscopy. The structure of Ni(pyr2en)·3H2O was determined by single-crystal X-ray diffraction. The pyr2en2, ligand is coordinated through two phenolate-O and imine-N atoms, in a distorted square-planar geometry. The complexation of CuII and NiII with Rpyr2en in aqueous solution is studied by pH-potentiometry, UV/Vis spectroscopy, as well as by EPR spectroscopy for the CuII system, and 1H NMR spectroscopy for the NiII system. Complex formation constants were determined and binding modes proposed. While for the CuII system all complexes present a 1:1 stoichiometry with different protonation states, for the NiII system the 2:1 (L/M) complexes become important in the basic pH range at a higher ligand excess. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Solar-thermochromism of Pseudocrystalline Nanodroplets of Ionic Liquid,NiII Complexes Immobilized inside Translucent Microporous PVDF Films

ADVANCED MATERIALS, Issue 7 2009
Xianjun Wei
Translucent composite films of poly(vinylidene fluoride), ionic liquid, and nickel complexes are successfully fabricated using thermal modulation of dissolution, casting, and drying. These films exhibit high stability in ambient storage and reversible thermochromic responses in air at temperatures achievable under sunlight, promising intelligent windows for controlling solar heat entering the built environment. [source]

Unexpected Condensation of 4,5-Dimethyl-1,2-phenylenediamine with Phthalaldehyde to 4,5-Dimethyldiisoindolo[2,1-a:1,2-c]quinoxaline-1,8-dione Initiated by NiII Complexes.

CHEMINFORM, Issue 31 2003
Igor L. Eremenko
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Highly Symmetrical Tetranuclear Cluster Complexes Supported by p - tert -Butylsulfonylcalix[4]arene as a Cluster-Forming Ligand

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 9 2006
Takashi Kajiwara
Abstract Square-planar tetranuclear clusters [M4(L)(AcO)4(,4 -OH)], (M = MnII, CoII, and NiII) are synthesized using tetra-anionic p - tert -butylsulfonylcalix[4]arene (L4,) as a cluster-forming ligand. Three complexes are crystallographically isostructural, being crystallized in the triclinic crystal system with space group P. The calix[4]arene acts as a tetrakis fac -tridentate ligand through four phenoxo and four sulfonyl oxygen atoms to form square arrangement of four metal ions, which are further bridged by four chelating acetate ions and one hydroxo ion in a ,4 manner to complete the hexacoordination of each metal center. Although the whole molecule of each complex is crystallographically independent, the molecule is highly symmetrical with a pseudo-four-fold axis lying on the ,4 -OH, group. The tetranuclear clusters are stable enough to maintain the core structures even in highly dilute solution (,10 ,M), which was confirmed by mass spectroscopic study, however, bridging acetates were easily exchanged by other carboxylate chelates to form derivatives such as [M4(L)(BzO)4(OH)],. Metal,metal interactions were investigated by means of magnetic susceptibility, and it was revealed that both ferro- and antiferromagnetic interactions occur in the NiII complex depending on the bridging angles of Ni,O,Ni. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Dinuclear Complexes of MII Thiocyanate (M = Ni and Cu) Containing a Tridentate Schiff-Base Ligand: Synthesis, Structural Diversity and Magnetic Properties

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2005
Suparna Banerjee
Abstract A dinuclear NiII complex, [Ni2(L)2(H2O)(NCS)2]·3H2O (1) in which the metal atoms are bridged by one water molecule and two ,2 -phenolate ions, and a thiocyanato-bridged dimeric CuII complex, [Cu(L)NCS]2 (2) [L = tridentate Schiff-base ligand, N -(3-aminopropyl)salicylaldimine, derived from 1:1 condensation of salicylaldehyde and 1,3-diaminopropane], have been synthesized and characterized by IR and UV/Vis spectroscopy, cyclic voltammetry and single-crystal X-ray diffraction studies. The structure of 1 consists of dinuclear units with crystallographic C2 symmetry in which each NiII atom is in a distorted octahedral environment. The Ni,O distance and the Ni,O,Ni angle, through the bridged water molecule, are 2.240(11) Å and 82.5(5)°, respectively. The structure of 2 consists of dinuclear units bridged asymmetrically by di-,1,3 -NCS ions; each CuII ion is in a square-pyramidal environment with , = 0.25. Variable-temperature magnetic susceptibility studies indicate the presence of dominant ferromagnetic exchange coupling in complex 1 with J = 3.1 cm,1, whereas complex 2 exhibits weak antiferromagnetic coupling between the CuII centers with J = ,1.7 cm,1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]

Structure, Characterization, and Metal-Complexation Properties of a New Tetraazamacrocycle Containing Two Phenolic Pendant Arms

HELVETICA CHIMICA ACTA, Issue 10 2004
Xiuling Cui
The new tetraazamacrocycle 2 (=2,2,-[[7-Methyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene-3,11-diyl]bis(methylene)]bis(4-bromophenol)) was synthesized and used as a ligand for different metal-ion complexes. The X-ray crystal structures of the complexes of the general formula [M(H- 2)]+NO,MeOH (M=Ni2+, Zn2+), in which only one of the two pendant phenolic OH groups of 2 is deprotonated, were determined. In both complexes, the coordination environment is of the [5+1] type, the four N-atoms of the macrocyclic framework defining a square-planar arrangement around the metal center, with similar NiN and ZnN distances of 1.961(9) to 2.157(9),Å and 2.021(9) to 2.284(8),Å, respectively. In contrast, the MO distances are markedly different, 2.060(6) and 2.449(8),Å in the NiII complex, and 2.027(7) and 2.941(9),Å in the ZnII complex. The UV/VIS spectra of the NiII and CuII complexes with ligand 2, and the EPR spectra of the CuII system, suggest the same type of structure for the complexes in solution as in the solid state. Theoretical studies by means of density functional theory (DFT) confirmed the experimental structures of the NiII and ZnII complexes, and led to a proposal of a similar structure for the corresponding CuII complex. The calculated EPR parameters for the latter and comparison with related data support this interpretation. The singly occupied molecular orbital (SOMO) in these systems is mainly made of a d orbital of Cu, with a strong antibonding (,*) contribution of the axially bound phenolate residue. [source]

Molecular Recognition of a Peptide by the Nickel(II) Complex of 1,4,7,10-Tetraazacyclododecane-2,9-dione

HELVETICA CHIMICA ACTA, Issue 3 2003
Jian Gao
The nickel(II) complex of the macrocycle 1,4,7,10-tetraazacyclododecane-2,9-dione (dota) was found to be efficient in the recognition of the dipeptide, glycyl-glycine (Gly-Gly) in aqueous solution. This (dota)NiII complex serves as a targeting molecule to form a stable ternary complex with the dipeptide at pH,8.3 in aqueous solution. The recognition constant (log K=19.20) and the recognition mechanism were investigated based on the potentiometric method. The single-crystal of a six-coordinated (dota)2NiII complex is also reported. [source]

A square-planar NiII complex with an asymmetric coordination of a novel polynucleative 2,6-diacetylpyridine bis{[2-(hydroxyimino)propanoyl]hydrazone} ligand

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2008
Maxym V. Plutenko
The title compound, (2,6-diacetylpyridine bis{[2-(hydroxyimino)propanoyl]hydrazone}(2,))nickel(II) dimethyl sulfoxide solvate monohydrate, [Ni(C15H17N7O4)]·C2H6OS·H2O, represents the first example of square-planar N4 coordination via N atoms with four different functions, namely amide, azomethine, hydroxyimino and pyridine. The coordination polyhedron of the central Ni atom has a slightly distorted square-planar geometry. The 2,6-diacetylpyridine bis{[2-(hydroxyimino)propanoyl]hydrazone} ligand forms one six- and two five-membered chelate rings, and a pseudo-chelate ring through an intramolecular hydrogen bond with an amide group as donor and a deprotonated hydroxyimino group as acceptor, resulting in a pseudomacrocyclic arrangement. [source]

[N,N,-Bis­(salicyl­idene)-2,2-di­methyl-1,3-propane­diaminato]­nickel(II) and [N,N,-bis­(salicyl­idene)-2,2-di­methyl-1,3-propane­diaminato]copper(II)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2001
Cengiz Arici
In the title compounds, {2,2,-[2,2-di­methyl-1,3-propane­diyl­bis­(nitrilo­methyl­idyne)]­diphenolato-,4N,N,,O,O,}nickel(II), [Ni(C19H20N2O2)], and {2,2,-[2,2-di­methyl-1,3-propane­diyl­bis­(nitrilo­methyl­idyne)]­diphenolato-,4N,N,,O,O,}copper(II), [Cu(C19H20N2O2)], the NiII and CuII atoms are coordinated by two iminic N and two phenolic O atoms of the N,N,-bis­(salicyl­idene)-2,2-di­methyl-1,3-propane­diaminate (SALPD2,, C17H16N2O22,) ligand. The geometry of the coordination sphere is planar in the case of the NiII complex and distorted towards tetrahedral for the CuII complex. Both complexes have a cis configuration imposed by the chelate ligand. The dihedral angles between the N/Ni/O and N/Cu/O coordination planes are 17.20,(6) and 35.13,(7)°, respectively. [source]

An Extremely Simple Dibenzopentalene Synthesis from 2-Bromo-1-ethynylbenzenes Using Nickel(0) Complexes: Construction of Its Derivatives with Various Functionalities

CHEMISTRY - A EUROPEAN JOURNAL, Issue 11 2009
Takeshi Kawase Prof.
Abstract Nice and easy: A very simple synthesis for dibenzopentalenes, which starts from 1-bromo-2-ethynylbenzenes, has been developed. It uses Ni0 complexes (see scheme), from which a relatively stable NiII complex as an important intermediate has been isolated. Dibenzopentalenes with various functional groups can be prepared by the procedure, and their electronic properties are consistent with theoretical calculations. An extremely simple dibenzopentalene synthesis from readily available 2-bromo-1-ethynylbenzenes using a nickel(0) complex is described. Although the yields are moderate, the formation of three CC bonds in a single process and the high availability of the starting materials are important advantages of this reaction. The corresponding aryl,nickel(II) complex as an important intermediate was isolated as relatively stable crystals, and the structure was confirmed by X-ray crystallographic analysis. The high stability of this complex should play a key role in this reaction. The reaction is applicable to the preparation of dibenzopentalenes bearing various functional groups. Their electronic properties are consistent with theoretical calculations. The cyclic voltammograms of these compounds reveal highly amphoteric redox properties. In particular, the electron-donating property of a tetramethoxy derivative is greater than that of oligothiophenes and dibenzodithiophenes and almost comparable to that of pentacene. [source]

Mono- and Binuclear Arylnickel Complexes of the ,-Diimine Bridging Ligand 2,2,-Bipyrimidine (bpym)

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2010
Axel Klein
Abstract The mono- and binuclear organometallic NiII complexes [(,-bpym){Ni(Mes)Br}n] (bpym = 2,2,-bipyrimidine; n = 1 or 2; Mes = mesityl = 2,4,6-trimethylphenyl) were prepared and characterised electrochemically and spectroscopically (NMR, UV/Vis/NIR) in detail. The long-wavelength absorptions for the binuclear complex reveal a marked electronic coupling of the two metal centres over the ligand bridge via their low-lying ,*-orbitals. While the mononuclear complex undergoes rapid dissociation of the bromido ligand after one-electron reduction the binuclear derivative exhibits reversible reductive electrochemistry and both of them yield stable radical anionic complexes with mainly bpym ligand centred spin density as shown by EPR spectroscopy of the free ligand bpym and the nickel complexes. The molecular structure of the binuclear bpym complex [(,-bpym){Ni(Mes)Br}2] was studied by EXAFS in comparison to the mononuclear analogue [(bpym)Ni(Mes)Br] revealing markedly increased Ni,C/N distance of the first coordination shell for the binuclear derivative suggesting an optimum overlap for the mononuclear complex, while two nickel complex fragments {Ni(Mes)Br} are seemingly too large to fit into the bis-chelate coordination site. [source]

Nickel Complexes with N2O Donor Ligands: Syntheses, Structures, Catalysis and Magnetic Studies

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 32 2007
Jishnunil Chakraborty
Abstract Two new terephthalato-bridged tetranuclear polymeric NiII complexes, namely [Ni4L41(,-tp-,4 -O)(H2O)2(,-tp-,2 -O)]·2C2H5OH·CH3OH·3H2O (1) and [Ni4L42(,-tp-,4 -O)(H2O)2(,-tp-,2 -O)]·3H2O (2) [L1 = N -(3-aminopropyl)-5-bromosalicylaldimine and L2 = N -(3-aminopropyl)salicylaldimine], are reported along with the syntheses and structures of the dicyanoargentate-bridged polymeric complexes [Ni(L1)(H2O){Ag(CN)2}], (3) and [Ni(L3)(MeOH){Ag(CN)2}], (4) [L3 = N -(3-amino-2,2-dimethylpropyl)-5-bromosalicylaldimine]. All four complexes are found to be effective heterogeneous catalysts for the epoxidation of alkenes such as styrene, ,-methylstyrene and cyclohexene in the presence of tert -butyl hydroperoxide. The variable-temperature magnetic susceptibility measurements (300,2 K) of complex 1 show a fair degree of antiferromagnetic coupling between the NiII centers.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Water-Soluble Sal2en- and Reduced Sal2en-Type Ligands: Study of Their CuII and NiII Complexes in the Solid State and in Solution

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2006
Isabel Correia
Abstract The CuII and NiII complexes of the Schiff base pyr2en [N,N, -ethylenebis(pyridoxyliminato)] and reduced Schiff bases Rpyr2en [N,N, -ethylenebis(pyridoxylaminato)] and R(SO3,sal)2en (SO3,sal = salicylaldehyde-5-sulfonate) were prepared and characterized by elemental analysis, IR, UV/Vis, and EPR spectroscopy. The structure of Ni(pyr2en)·3H2O was determined by single-crystal X-ray diffraction. The pyr2en2, ligand is coordinated through two phenolate-O and imine-N atoms, in a distorted square-planar geometry. The complexation of CuII and NiII with Rpyr2en in aqueous solution is studied by pH-potentiometry, UV/Vis spectroscopy, as well as by EPR spectroscopy for the CuII system, and 1H NMR spectroscopy for the NiII system. Complex formation constants were determined and binding modes proposed. While for the CuII system all complexes present a 1:1 stoichiometry with different protonation states, for the NiII system the 2:1 (L/M) complexes become important in the basic pH range at a higher ligand excess. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]

Inverse bilayer structure of mononuclear CoII and NiII complexes of the type M(H2O)3(SO4)(4-CNpy)2

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2009
Birinchi K. Das
Two new metal compounds of the formula [M(H2O)3(SO4)(4-CNpy)2]·H2O [M = Ni (1) and Co (2), 4-CNpy = 4-cyanopyridine] have been prepared and studied by X-ray diffraction. In both of these compounds the 4-CNpy ligands are coordinated via pyridyl-N atoms to the metal ions in a cis fashion. The neutral complexes along with the uncoordinated H2O molecules are glued together preferentially into inverse bilayers by non-covalent interactions, including unique interlayer ,,, interactions between antiparallel nitrile groups. Hartree,Fock and density-functional theory (DFT) calculations indicate that the ,,, interactions are energetically significant. The unit-cell similarity index (,) of 0.0046 for the compounds suggests their isostructurality, which is also supported by their X-ray powder diffraction patterns that can be almost superimposed. [source]