Preparation and crystal structure of a copper(II) uranyl(VI) binuclear chelate

Summary The structure of the heterobinuclear complex of Cu²⁺ and [UO₂]²⁺ with the tetraanionic ligand derived from the condensation of 1,2-diaminoethane witho-acetoacetylphenol has been determined from diffractometer data and refined to R = 5.2%. The crystals are monoclinic,P2₁/a, witha = 26.22(2),b = 14.79(2),c = 8.10(1) Å and = 104.65(5)°; Z = 4. The ligand employed has two different coordination sets of atoms, N₂O₂ and O₂O₂, two oxygen atoms being common to both donor sets. In the complex the copper atom, which is retained in the inner N₂O₂ chamber, is five coordinate being axially bonded to a solvent molecule, whilst the uranyl ion is incorporated in the outer O₂O₂ chamber. Another molecule of solvent is retained to preserve the preferred seven coordination of uranium.     

Preparation and crystal structure of a copper(II) homobinuclear chelate

Summary The structure of the homobinuclear complex Cu₂(aapen)H₂O, where aapen is the tetraanionic ligand derived from the condensation of 1,2-diaminocthane witho-acetoacetylphenol, has been determined from diffractometer data and refined to R = 6.1%. The crystals are monoclinic,P2₁/c, witha = 12.991(5),b = 8.530(4),c = 18.546(6) Å, and = 104.10(4)°; Z = 4. The ligand employed has two different coordination sets of atoms, N₂O₂ and O₂O₂, two oxygen atoms being common to both donor sets. In the complex, one copper atom is retained in the plane of the inner N₂O₂ chamber whilst the other, which is incorporated in the outer O₂O₂ chamber, is five-coordinate, being axially bonded to a water molecule.     

Synthesis,crystal structure and magnetic properties of N -benzesulfonyl-L-glutamic acid-bridged binuclear nickel(II) complex

N-benzesulfonyl-L-glutamic acid-bridged binuclear nickel(II) complex, [Ni₂(Bs-Glu)₂(bipy)₂ (H₂O)₂]?·?3H₂O (Bs-Glu?=?N-benzesulfonyl-L-glutamic acid dianion, bipy?=?2,2′-bipyridine), has been synthesized and characterized structurally and magnetically. It crystallizes in the triclinic space group P 1. The α-carboxyl group coordinates to Ni(II) in a monodentate mode, while the γ-carboxyl group coordinates in a chelating mode. In the temperature range 2–300?K, magnetic measurements show that the exchange interaction of the two Ni(II) ions is antiferromagnetic, and the values for J, g are ?2.47?cm^?1 and 2.18, respectively.     

Synthesis, magnetism and crystal structure of a chloride-bridged binuclear nickel(II) complex of tris(2-pyridylmethyl)amine

Summary A new binuclear Ni^II complex, [{(TPA)Ni(-Cl)}₂]-(ClO₄)₂·H₂O (1), where TPA = tris(2-pyridyl-methyl) amine, has been prepared and characterized. The X-ray crystal structure and variable temperature magnetic susceptibility (4–300 K) of the complex have been determined. The two Ni^II atoms of (1) are in a distorted octahedral environment and are bridged by Cl atoms. Ni-Cl distances are 2.363(6) and 2.503(7) Å, and the Ni-Cl-Ni angle is 92.7(2)°. The metal atoms are separated by a non-bonding distance of 3.523 Å.The effective magnetic moment of (1) increases slightly with decreasing temperature and appears to reach a maximum before decreasing. The observed data were fitted to the Heisenberg model and the results indicate that there is a ferromagnetic interaction (positive J) and weak antiferromagnetic intermolecular interaction (negative ).     

Electronic structure and X-ray spectra of nickel(II) dithiolate chelate complexes

Nickel(II) dithiocarbamate and dithiophosphinate complexes were studied by X-ray and X-ray photoelectron spectroscopy. The X-ray emission and absorption spectra of Ni(II) compounds were interpreted in terms of quantum-chemical model calculations of the electronic spectrum of the complexes. The electronic structure of nickel(II) dithiolates was analyzed on the basis of the experimental and theoretical data.     

Preparation and characterization of metal complexes containing a NS donor ligand derived from S-benzyldithiocarbazate and p-nitrobenzaldehyde. X-ray crystal structure of the nickel(II) chelate

Summary A series of metal (Cu, Ni, Zn, Cd and Pd) complexes of a Schiff base ligand derived from S-benzyldithiocarbazate and p-nitrobenzaldehyde were prepared and characterized. The Schiff base acts as a single negatively-charged bidentate ligand forming stable neutral metal complexes. Magnetic and spectroscopic data suggest a square planar structure for the Cu^II, Ni^II and Pd^II chelates. Single X-ray diffraction analysis of the Ni^II chelate established that the Schiff base loses a proton from its tautomeric thiol form and coordinates to the metal via the thiolato sulfur and -nitrogen. The geometry around Ni^II is square planar with two equivalent Ni-N and Ni-S bonds; the two nitrobenzyl rings and the coordination plane are almost isoplanar, giving a delocalized electronic system.     

Synthesis and crystal structure of diaquadibenzoatobis(nicotinamide)nickel(II)

A coordination compound of nickel(II) benzoate with nicotinamide [Ni(C₆H₅COO)₂(L)₂(H₂O)₂] (I) (L is nicotinic acid amide) is synthesized and studied by IR spectroscopy. Its crystal structure is solved by X-ray crystallography. The crystals of compound I are monoclinic: a = 7.152 Å, b = 18.266 Å, c = 10.341 Å, β = 109.24°, V = 1275.4 ų, Z = 2, space group P2₁/c. Structural units of a crystal of I are centrosymmetric octahedral complex molecules. The coordination environment of the Ni atom contains two O atoms (Ni-O(1) 2.066(2) Å) and two N atoms (Ni-N(1) 2.091(2) Å) of the monodentate-coordinated benzoate anions and nicotinamide molecules, respectively, as well as two O atoms of the H₂O molecules (Ni-O(1w) 2.110(2) Å).     

Synthesis and crystal structure of bis(dimethylthioacetonedicarboxylate)nickel(II)

Summary The title compound has been synthesized and characterized. The crystal structure has been determined by single-crystal x-ray analysis from diffractometer data, and refined to R= 0.063 for 1889 observed reflections. Crystals are monoclinic, space group P2₁/n, witha=21.97(2),b=8.21(1),c=10.44(1) A, and =101.87(3), and Z=4. Both ligands are coordinated to nickel through sulphur and one oxygen atom to realize thecis form of the complex in the square planar coordination geometry. Bond distances are: Ni-S, 2.14(1), Ni-O, 1.87(1) and 1.90(1) Å. Each nickel atom also forms two close contacts with oxygen atoms from adjacent molecules.     

Synthesis and crystal structure of dinuclear nickel (Ⅱ) complex

The crystal structure of Ni(Ⅱ) complex with 3-hydroxyl-1, 5-diazacycloheptane-N, N'-diacetate was determined by X-ray diffraction method. Crystal data for Ni2 (C9H14N2O5)2·2H2O: monoclinic, space group P21/n, a = 1.1717(5), b = 0.9794(3), c = 1.2971(2) nm, β= 96.62(3), V= 1.4786(7) nm3, Dc = 1.377 g/cm3, Z = 2,μ=13.321 cm-1 (Mo-Kα), F(000)=640. The final R and Rw are 0.075 and 0.089 respectively. The Ni(Ⅱ) ion forms 2:2 complex with ligand. Two ligands are bridged by two Ni(Ⅱ) atoms which are bridged by two O atoms. Every Ni(Ⅱ) is coordinated by two N atoms and four 0 atoms. The coordination polyhedron of the Ni(Ⅱ) ion is a distorted octahedron.     

Synthesis and crystal structure of hydrated cation-anion nickel(II) thiosemicarbazide and nickel(II) malonate dihydrate complex

A crystal of Ni(HL)₂[Ni(Malon)₂(H₂O)₂]₂ · 3.51H₂O (I), which is built of [Ni(HL)₂]₂₊ cations (HL is thiosemicarbazide), [Ni(Malon)₂(H₂O)₂]_2? anions (H₂ Malon is malonic acid), and molecules of crystal water, has been synthesized and studied by IR spectroscopy, thermogravimetry, and X-ray diffraction. Structural units of complex I are linked by electrostatic interactions and numerous hydrogen bonds. The unit cell parameters b = 7.233(1) Å, c = 24.426(5) Å, β = 127.98(3)°, space group C2/c, Z = 8. The polyhedron of the nickel atom in [Ni(HL)₂]₂₊ cations is a cis-square that is slightly distorted within ～10°. Ligands HL are bidentately chelately coordinated (via N and S) to the nickel atom with the closure of near planar five-membered chelate rings. The malonate groups in [Ni(Malon)₂(H₂O)₂]^2? anions are bidentately chelately coordinated with the formation of six-membered non-planar chelate rings. The coordination of the central atom is complemented to an octahedron with two H₂O molecules. The bond lengths in cations are 1.924(4) and 1.912(4) Å (Ni-N) and 2.144(1) and 2.150(2) Å (Ni-S), and the bond lengths in anions are 2.003–2.046(3) Å (Ni-O) and 2.113(4) and 2.122(3) Å (Ni-O(w)).     

Preparation and crystal structure of dual-functional precursor complex bis(acetylacetonato)nickel(II) with 4-pyridyltetrathiafulvalene

A tetrathiafulvalene (TTF) derivative 4-pyridyltetrathiafulvalene (Py-TTF) was synthesized. The 1:2 Ni complex 1 of bis(acetylacetonato)nickel(II) coordinated with Py-TTF was prepared. Complex 1 crystallizes in the monoclinic space group P2(1)/c. Two pyridyl N atoms from two different molecules of Py-TTF are coordinated in the trans configuration to the Ni ion of Ni(acac)2 to form an octahedral Ni complex, which is a precursor for both conducting and magnetic materials.     

Synthesis and crystal structure of a phosphite nickel(II) 8-mercaptoquinoline complex

A monomeric trimethylphosphite nickel(II) complex of 8-mercaptoquinoline (Hmtq), [Ni(mtq)P(OMe)3]Cl, was synthesised and characterised by X-crystallography, FAB-MS and cyclic voltammogram measurements. The nickel(II) atom is co-ordinated via the S and N atoms of the mtq– entity, one P(OMe)3 ligand and one Cl– anion in a square-planar geometry. Two types of main fragment ions were observed in the FAB mass spectrum of the title complex: Cl– followed by P(OMe)3. The electrochemical behaviour of the title complex in MeCN solution with n-Bu4NBF4 (0.1molL–1) as electrolyte on the Pt electrode indicates that the reversible redox reaction [Ni(mtq)P(OMe)3]+ + e [Ni(mtq)P(OMe)]0 has occured in MeCN.     

Synthesis and crystal structure of mononuclear nickel(II) trifloroacetate complex

Russian Journal of General Chemistry -     

Synthesis,crystal structure and magnetic properties of a new macrocyclic binuclear copper(II) complex

A new binuclear copper complex [CuLCl₂]₂, [L = 1-(p-tolylsulfonyl)-1,4,7- triazacyclononane], has been synthesized and structured as well as magnetically characterized. In the complex, each copper(II) atom is located in the center of a distorted square pyramidal configuration of five coordinating atoms (two nitrogen atom and three chlorine atom). Two copper(II) atoms were bridged by two chlorine anions (Cl1 and Cl1a). The distance between two copper(II) atoms is 3.483 Å. An antiferromagnetic exchange coupling effect exists in the complex.     

Synthesis,crystal structure and magnetic properties of a new binuclear copper(II)-copper(II) complex of a macrocyclic oxamide

The binuclear metal complex [Cu(μ-exoO₂)cyclamCu(bpy)](ClO₄)₂·H₂O (bpy?=?2,2′-bipyridine and (exoO₂)cyclam?=?1,4,8,11-tetraazacyclotradecanne-2,3-dione) has been synthesized and characterized by single-crystal X-ray analysis and spectroscopic and magnetic measurements. The structure consists of homobinuclear [Cu(μ-exoO₂)cyclamCu(bpy)]²⁺ cations, a weakly coordinated water molecule and perchlorate ions. In each binuclear unit, Cu1, coordinated by four nitrogen atoms of the macrocyclic organic ligand is connected to Cu2 via the exo-cis oxygen atoms of the macrocyclic ligand with Cu···Cu separations of 5.151?Å; Cu2 assumes square-pyramidal geometry. Magnetic properties measured at 2–300?K show antiferromagnetic exchange between adjacent copper(II) ions.     

Synthesis and catalytic activity of binuclear cobalt(II) and nickel(II) complexes

Summary Binuclear Ni^II and Co^II complexes derived from 2,6-diformyl-4-methylphenol and various aromatic monoamines have been prepared and investigated. The Ni^II complexes have Ni₂LCl₃ composition while the Co^II complexes have Co₂L₂Cl₂ composition, where L represents the organic ligand. The complexes are active catalysts in the oxidation of 3,5-di-t-butylcatechol (3,5-DTBC) by dioxygen, but less so than their Cu analogues. This result is attributed to the absence of antiferromagnetic coupling between the metal centres.     

Synthesis and crystal structure of aqua(diaminobithiazole) (iminodiacetato)nickel(II) hydrate

Crystals of the title compound, [(C₆H₆N₄S₂)(C₄H₅NO₄)(H₂O)Ni]·H₂O, consist of the Ni(II) complex and lattice water. The Ni(II) complex adopts a distorted octahedral coordination geometry formed by an iminodiacetate anion (IDA), a diaminobithiazole (DABT) and a coordinated water molecule. A twisted configuration of DABT is the distinguishing feature in the complex, the dihedral angle between thiazole rings of DABT being 20.04(8)°. An aromatic stacking interaction occurs between thiazole rings from neighboring complex molecules, and is considered as the reason for the twisted configuration. The tridentate IDA dianion chelates to a Ni(II) atom in afacialconfiguration. A hydrogen bond network holds the complex molecules together to form a supramolecular structure.     

Synthesis,crystal structure,and DNA binding of a new oxalato-bridged binuclear zinc(II) complex

A new binuclear zinc(II) complex bridged by μ-oxalate, and end-capped with 2,2′-bipyridine (bpy), [Zn₂(ox)(bpy)₄](ClO₄)₂ · H₂O, has been synthesized and characterized by elemental analyses, molar conductance, IR, and electronic spectra and single-crystal X-ray diffraction. The single-crystal X-ray analysis reveals that the [Zn₂(ox)(bpy)₄]²⁺ cation has two zinc(II) centers bridged by a planar bis(bidentate) oxalate group with Zn···Zn distance of 5.482(3) Å; each zinc(II) is in a distorted octahedral environment. The crystal structure is stabilized by non-classical C–H···O hydrogen bonds and π–π stacking interactions to form a 3-D supramolecular structure. The interaction of the complex with calf-thymus DNA (CT-DNA) was explored by using electronic and fluorescence spectra and viscosity measurements. The results reveal that the complex intercalates with CT-DNA with intrinsic binding constant of 4.1 × 10⁴ M^?1.     

Magnetic properties of binuclear high-spin trimethylacetate nickel(II) complexes

The static magnetic susceptibility of mononuclear trimethylacetate nickel complex Ni(NH₂Ph)₄(OOCCMe₃)₂ (3) and binuclear complexes Ni₂(μ-OH₂)(μ-OOCCMe₃)₂(OOCCMe₃)₂(dipy)₂ (4) and Ni₂(μ-OOCCMe₃)₄py₂ (5) was measured in the temperature range of 2–300 K. The magnetic behavior of3 is typical of mononuclear complexes with the Ni¹¹ atom in the octahedral environment. Numerical calculations of the temperature dependence of magnetic susceptibility with inclusion of isotropic exchange interactions (J) and single-ion initial splitting parameters showed that the magnetic behavior of complexes4 and 5 can be interpreted in terms of ferromagnetic (for4) and antiferromagnetic (for5) interactions. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 437–442, March, 2000.