Synthesis,Crystal Structure and Magnetic Properties of an Oxalato-Bridged Dinickel(II) Complex Containing A MacrocyClic Ligand

A new binuclear nickel(II) complex [Ni(µ-C₂O₄)(rac-cth)₂](ClO₄)₂[rac-cth = rac -5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane] has been prepared and its structure determined. It consists of centrosymmetric [Ni( µ -C₂O₄)(rac-cth)₂]²⁺ cations separated by perchlorate anions, with a centre of symmetry lying in the middle of the C-C bond of the bis-bidentate oxalate bridge. The tetraazamacrocycle adopts a folded conformation around the nickel atom, which is six coordinated in a distorted octahedral arrangement. Variable temperature magnetic susceptibility measurements (4-300 K) suggest a moderate intramolecular antiferromagnetic interaction between the metal ions ( J = -34.0 cm^-1, g = 2.07)     

Cyano-bridged Heterotrinuclear Molybdenum(IV)-Nickel(II) Complexes: Synthesis,Crystal Structure and Magnetic Properties

Two novel cyano-bridged heterotrinuclear molybdenum(IV)-nickel(II) complexes ([Ni(en)₂(H₂O)]_2-[Mo(CN)₈]·2H₂O, 1, and [NiL(H₂O)]₂[Mo(CN)₈]·4H₂O, 2), where en=1,2-diaminoethane and L= 1,3,6,9, 11,14-hexaazacyclo[12,2,1,1^6,9]octodecanne were synthesized and characterized. The crystal structure of 1 was determined. The structure consists of trinuclear units, space group C2/c, with unit cell dimensions a=17.178(9), b=11.032(5), c=17.629(8) Å, α=108.484(8)°. The temperature dependence of the magnetic susceptibilities for 1 and 2 was analyzed by means of a Hamiltonian expression leading to J=-0.87cm^-1, ZJ'=0.65cm^-1, D=0.02cm^-1, g _Ni=2.45 for complex 1, and J=-0.87cm^-1, ZJ'=0.56cm^-1, D=0.02cm^-1, g, _Ni=2.45 for complex 2.     

Crystal Structure and Magnetic Properties of a Copper(II) Chloride Complex with Nitronyl Nitroxide

A new compound [Cu(NITPhCH₃)₂Cl₂] (NITPhCH₃ 2-(4-methyl-phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) has been characterized spectroscopically. A crystal structure analysis has shown the copper ion to be planar, coordinated by two chlorine atoms and two oxygen (nitroxyl) atoms. Based on magnetic susceptibility measurements the compound was found to exhibit a moderately strong antiferromagnetic interaction (J= m 107.44 cm_-1) between copper(II) and the radical.     

A New Azide-Bridged Three-Dimensional Supramolecular Manganese(II) Compound: Synthesis,Crystal Structure and Magnetic Properties

A three-dimensional supramolecular compound [Mn(N₃)₂(H₂O)₃(hmt)] ₂ , where hmt stands for hexamethylenetetramine, was synthesized and characterized by IR, crystal structure and magnetic susceptibility. The compound [Mn(N₃)₂(H₂O)₃(hmt)] _n , crystallizes in the orthorhombic system, space group P_n 2₁ a, with a = 6.5201(9), b = 9.322(2), c = 22.192(3) Å, β = 90° and Z = 2. The Mn atom is coordinated in an octahedral arrangement by three nitrogen atoms from three azido ions, and three oxygen atoms from three water molecules, respectively. The azide ligand bridges Mn atoms in μ-1,3 fashion, forming a zigzag chain. Hmt connected with the zigzag chain by hydrogen bonds, to form a three-dimensional supramolecular structure. The magnetic susceptibility data show that there is an antiferromagnetic exchange interaction in the title compound. The data were modeled using an infinite chain model leading to J = -4.8 cm^?1.     

Synthesis,Structure and Magnetic Properties of a Novel Nickel(II) Radical Heterospin Complex with Salicylaldoxime

A novel heterospin complex containing both Ni^II and nitroxide radical ligands: [Ni(salox)₂(NIT4Py)₂] ( 1 ) (salox = salicylaldoxime, NIT4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐ tetramethyl‐imidazoline‐1‐oxyl‐3‐oxide) has been synthesized and structurally characterized. The structure consists of neutral Ni(salox)₂(NIT4Py)₂ moieties bridged by intermolecular hydrogen bonds, forming a one‐dimensional chain structure. Magnetic measurements show intramolecular antiferromagnetic interactions between NIT4Py and Ni²⁺ ion.     

Synthesis,Characterization and Crystal Structure of a Nickel(II) Schiff Base Complex Derived from Acetylacetone and Ethylenediamine

The square-planar nickel (II) complex of composition [Ni(bae)]·½H₂O (1) [where H₂bae is bis(acetylacetone)ethylenediamine] has been synthesized by [2 + 1] template condensation of acetylacetone and ethylenediamine in the presence of NiCl₂·6H₂O and characterized. An X-ray structure determination of the complex has been completed. Average Ni-N and Ni-O distances are, respectively, 1.86(2) Å and 1.849(14) Å. N···N bite distance and bite angle are 2.627(6) Å and 87.2(2)°, respectively, for the five-membered chelate ring. The water molecule forms hydrogen bonds with O atoms of two complex molecules.     

Synthesis and Crystal Structure of a Fumaratocopper(II) Complex with Bipyridine

The title complex [Cu₂(C₄H₂O₄)₂(bipy)₂(H₂O)₃] · 3H₂O (bipy = 2,2'-bipyridine) was prepared and its crystal structure determined by X-ray diffraction methods. Both Cu(II) atoms of the binuclear complex assume square pyramidal coordination. The fumarate groups display different coordination modes. One fumarate group bridges two Cu(II) ions to form a binuclear complex while another fumarate group terminally coordinates to a Cu(II) atom with one carboxyl group free from coordination. The terminally coordinated fumarate showed unusual disorder, which may be due to an intermolecular H-bonding interaction. Close stacking of bipy rings is observed as verified by the distance of 3.46 Å between parallel ring planes. IR spectra were assigned based on the molecular structure.     

Synthesis,Structure and Properties of an Oxalato-Bridged Dinuclear Nickel(II) Complex

A new dinuclear nickel(II) compound, [Ni₂(TPA)2(μ-C₂O₄)](H₂O)_0.75(ClO₄)₂ [TPA = tris(2-pyridylmethyl) amine], was synthesized and characterized by electronic spectroscopy and X-ray methods. In the complex, the oxalate ion acts as a bis-bidentate ligand and the two Ni(II) ions are six coordinated with a distorted octahedral structure. The complex crystallizes in the triclinic space group P_i , with a = 13.203(4), b = 16.574(5), c = 21.802(6) Å, α = 78.644(5), β = 80.299(5), γ = 72.446(5)°, V = 4429 ų, Z = 2; R ₁ = 0.0615, wR ₂ = 0.1639. In the temperature range 4-300 K, magnetic measurements show that the exchange interaction between the two metal ions is antiferromagnetic with J = ? 18.74 cm^?1, g = 2.10.     

Synthesis,Crystal Structure and Characterization of Polynuclear Potassium(I), Copper(II) and Cobalt(II) Complex with Acetylacetonethylenediamine

The title complex [K{Cu(acen)}₃]₂[Co(NCS)₄]·1/4CH₃OH (acen = acetylacetonethylenediamine anion) has been prepared and characterized. Single-crystal x-ray analysis reveals that the complex crystallizes in space group P I with a = 11.442(2), b = 15.098(3), c = 28.500(4) Å, α = 82.77(1), β = 83.58(1), γ = 85.07(1)°. The crystal consists of the complex [K{Cu(acen)}₃]⁺ cations, [Co(NCS)₄]^2? anions and methanol molecules. Three [Cu(acen)] molecules function as bridging ligands through phenolic O atoms to one K⁺ to give the tetranuclear [K{Cu(acen)}₃]⁺ cation. Each copper(II) atom in the cation is in a square-planar geometry, being coordinated by two oxygen atoms and two nitrogen atoms from a quadridentate acen ligand. The cobalt(II) atom is coordinated by four nitrogen atoms of thiocyanate ligands, forming a deformed tetrahedral environment. The IR and UV-Vis spectra have also been investigated.     

Synthesis,Crystal Structure and Magnetic Property of Copper(II) Complex with 4′-Cyanobenzyl-1-imidazol

A neutral mononuclear complex [Cu(cbIm)₄(NO₃)₂] (cbIm = 4'-cyanobenzyl-1-imidazol) was synthesized and characterized by x-ray crystallography. It crystallizes in the triclinic space group P-1 with a = 8.249(2), b = 8.735(2), c = 16.597(2) Å, f = 81.980(10), g = 88.540(10), n = 63.570(10)° and Z = 2. The final refinement of the structure leads to R and Rw of 0.0394 and 0.0991, respectively. The crystal structure of the complex indicates a distorted octahedral environment around the Cu(II) atom, coordinated by four imidazole N atoms of four cbIm and two O atoms of two nitrates. Magnetic measurements show that the complex exhibits Curie behavior.     

Synthesis,Characterization and Crystal Structure of a Ternary Cu(II) Complex with 1,10-Phenanthroline and l-Leucinate

The complex [Cu(l-Leu)(phen)(H₂O)]NO₃ has been synthesized and characterized by elemental analysis, molar conductivity, spectroscopic and X-ray diffraction methods, where phen = 1,10-phenanthroline and l-Leu = l-leucinate. The complex crystallizes in the triclinic space group Pī with two molecules in a unit cell of dimensions a = 7.288(4) Å, b = 11.588(7) Å, c = 12.349(3) Å, α = 86.388(10)^o, β = 76.175(11)°, γ = 72.132(3)°, V = 963.8(10) ų, Z = 2, D _c = 1.564 g/cm³, μ = 1.177 mm^?1, F(000) = 470, R ₁ = 0.0611, and wR ₂ = 0.0711. The copper(II) is ligated in a distorted square-pyramidal geometry by the two nitrogen atoms of phen and the amino nitrogen atom and one carboxylate oxygen atom from each independent l-Leu moiety in the basal plane, and one water oxygen at the apical position. A supramolecular configuration is formed from strong phen-phen stacking interactions between neighboring [Cu(l-leu)(phen)(H₂O)]⁺cations in the crystal.     

Synthesis,Properties and X-ray Crystal Structures of Nickel(II) Complexes of a Hexaazamacrotetracyclic Ligand

The complexes [N₂(L²)₂(H₂O)₄]Cl₄(1) and [Ni(L²)](ClO₄)₂ [sdot]2H₂O (2) (L = 1,3,10,12,16,19-hexaazatetracyclo [17,3,1,1 ^12.16,0^4.9]tetracosane) have been synthesized and structurally characterized by X-ray crystallography, spectroscopic and cyclic voltammetry. The crystal structure of 1 has a distorted octahedral geometry with two secondary and two tertiary amines of the macrocycle and two water molecules. In 2, the coordination geometry around the nickel atom is square-planar with four nitrogen atoms of the macrocycle. The equilibrium [Ni(L²)]²⁺ + 2H₂O &rlhar2; [Ni(L²)(H₂O)₂]²⁺ has been studied in aqueous solution over a temperature range, yielding Δ H° = -19.0 ± 0.2 kJ mol^-1 and Δ S° = - 56.0 ± 0.4 JK^-1 mol^-1. Cyclic voltammetry of the complexes give two one-electron waves corresponding to Ni(II)/Ni(III) and Ni(II)/Ni(I) processes. The electronic spectra and redox potentials of the complexes are influenced significantly by the geometry.     

Synthesis and Crystal Structure of a 1,3-Benzenedicarboxylatomanganese(II) Complex with 2,2-Bipyridine

The title complex has been prepared by the reaction of Mn(2,2'-bipy)Cl 2 with 1,3-benzenedicarboxylate (BDC) in ethanol solution. The complex crystallizes in space group C 2/ c with a =13.847(6), b =15.629(7), c =17.106(6) Å, g =107.90(3)° and z =8. Three BDC and one bipy ligands coordinate to Mn(II) to form a distorted octahedron. Each BDC bridges three Mn(II) atoms to form a polymeric chain. It is notable that although the Mn(II) atom deviates 1.084 Å from the bridging carboxyl plane it still has a normal coordination distance of 2.141(2) Å. This might suggest an electrostatic interaction between Mn(II) and carboxyl O atoms in the title complex. The IR spectrum is discussed, based on the molecular structure.     

Synthesis and Crystal Structure of a Cadmium Complex with Isonicotinate

The cadmium(II) complex, [Cd(iso) 2 (H 2 O) 4 ] (where iso is the anion of isonicotinic acid), has been synthesized and characterized by element analysis, thermal analysis and IR spectroscopy. An X-ray crystal structure reveals that the cadmium ion is trans -octahedral with two pyridyl nitrogens and two aqua oxygens in equational positions and two aqua oxygens in axial positions. The complex forms a three-dimensional network through intermolecular hydrogen bonds.     

Synthesis,Crystal Structure and Magnetic Properties of Diaqua(1,10-Phenanthroline-N,N')-Hydrogenmaleatocopper(Ii) Hydrogenmaleate Monohydrate

Reaction of freshly-prepared CuCO₃, phenanthroline monohydrate and maleic acid in CH₃OH/H₂O(1 : 1 v/v) at pH=2.13 yielded diaqua(1,10-phenanthroline-N,N')hydrogenmaleatocopper(II) hydrogenmaleate monohydrate, [Cu(phen)(H₂O)₂(C₄H₃O₄)](C₄H₃O₄)(H₂O), which consists of [Cu(phen)(H₂O)₂(C₄H₃O₄)]⁺ complex cations, hydrogenmaleate anions and lattice H₂O molecules. Within the complex cations, the Cu atoms are each square-pyramidally coordinated by two N atoms of one chelating phen ligand and three O atoms of two H₂O molecules and one hydrogenmaleato ligand with one H₂O molecule at the apical position (d(Cu-N) = 2.001, 2.009 Å, equatorial d(Cu-O) = 1.966 Å and axial d(Cu-O) = 2.235 Å). Through hydrogen bonding, the complex cations, hydrogenmaleate anions and lattice H₂O molecules are assembled into 1D chains, which are held together by weak Cu···O interactions (3.139 Å) to form corrugated 2D layers. Significant π-π stacking interactions between neighboring phen ligands leads to supramolecular assembly of the 2D layers. Over the temperature range 5-300 K, the complex obeys the Currie-Weiss law with an effective magnetic moment of 1.78 BM at room temperature.     

Synthesis, Structure and Magnetic Properties of a Diphenoxo-bridged Binuclear Copper(II) Complex

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Synthesis,Crystal Structure,and Properties of a Binuclear Copper(II) Complex Containing an Oxalate Bridge

The complex [Cu₂(L)₂(μ₂‐C₂O₄)]·CH₃OH ( 1 ) has been synthesized and characterized by IR, UV, ESR and variable temperature magnetic susceptibility measurement, where L = 1‐(ethylamino)‐2‐(salicylideneamino)ethane. The crystal X‐ray diffraction reveals that complex 1 has a μ₂‐C₂O₄^2— bridge. The complex exhibits ferromagnetic couplings between the copper atoms bridged by oxalate dianion, which is rare in oxalato‐bridged copper complexes.     

Synthesis and Crystal Structure of an Mn(II) Complex with Benzoylacetone

The complex (benzoato)benzoylacetonato(bipyridine)Mn(II) has been prepared and its crystal structure determined by X-ray diffraction methods. Benzoic acid, benzoylacetone (bzac) and 2,2'-bipyridine all chelate to Mn(II) to form a six coordinate complex. As bond angles around the Mn(II) atom greatly deviate from those expected for an octahedron, the coordination geometry may be described as distorted pyramidal with a bidentate carboxyl group occupying the apex of the pyramid. Although the Mn atom deviates by 0.550 Å from the enol ring plane of bzac, Mn-O distances [2.105(2) and 2.098(2) Å] are normal. This suggests the existence of electrostatic interactions between Mn(II) and the bzac ligand.     

Synthesis,Structure and Properties of a Zinc(II) Complex with the Lapacholate Anion and Ethanol as Ligands

The reaction of lapachol, 2-hydroxy-3-(3-methyl-2-butenyl)-1,4-naphtoquinone, C₁₅H₁₄O₃, with zinc acetate, in ethanol, produces a chelate formula Zn(C₁₅H₁₃O₃)₂(C₂H₆O)₂, whose structure has been determined by single crystal X-ray diffraction. It pertains to the triclinic system, space group P I (No. 2), a = 8.2380(3) Å, b = 9.4900(2) Å, c = 11.0110(4) Å, α = 112.536(2)°, β = 91.204(2)°, γ = 92.664(2)°, Z = 1. Some spectroscopic and chemical properties of the complex are also reported.     

Synthesis,Structure and Magnitic Properties of a Diphenoxobridged Binuclear Copper（Ⅲ） Complex

A mixed-ligand copper(Ⅱ） complex[Cu2(phen)2(HL^1)2]-(ClO4)2(1) was synthesized.X-ray analyses reveal that 1 has a bis(μ2-phenoxo)-bridged dicopper(Ⅱ） structure.2D hydrogen-bonded network is formed utilizing the N-H,O-H and C-H groups of the (HL^1) ligands (H2L^1=N-(2-hydroxybenzyl)ethanolamine),the C-H groups of the phenanthrolines and the perchlorate anions.Variable temperature magnetic properties of 1 have shown comparatively weak antiferromagnetic interactions with respect to the bridge angles, which have been ascribed to the unfavorable overlaps of the magnetic orbitals fo the highly distorted copper coordination polyhedra and the pyramidal distortions at the phenoxo oxygen atoms.