The formation of a Schiff base intermediate: a nickel(II) complex of an asymmetric tripodal ligand

Treatment of Ni(ClO₄)₂ · 6H₂O with the condensing product of 2-formylpyridine N-oxide and 1,5-diamino-3-(8-methylquinolyl)azapentane (dmqa) has resulted in the formation of an asymmetric tripodal nickel(II) complex, [C₂₈H₃₂N₆O₃Ni](ClO₄)₂ · H₂O, which has been crystallographically characterized. Crystal data: triclinic, space group p , a = 10.384(2), b = 10.911(3), c = 16.6101(11) Å, = 95.62(2), = 105.04(2), = 112.954(11)°, D _c = 1.581 g/cm³, Z = 2 and V = 1631.0(6) ų. A quinoline moiety is first introduced into an arm in the complex of a tripodal ligand in which an ethylcarbinoxyamine group, the intermediate of Schiff bases, exists.     

Structural and spectral studies of binuclear copper(II) 2-acetylpyridine 3-azacyclothiosemicarbazones with sulfato bridges

Structures of two binuclear copper(II) complexes with sulfato bridges and tridentate 2-acetylpyridine 3-azacyclothiosemicarbazone ligands have been solved. The complex-sulfato-bis{(2-acetylpyridine 3-hexamethyleneiminyl-thiosemicarbazonato)copper(II)} N,N-dimethylformamide, [Cu(Achexim)]₂SO₄·DMF, has the following structural properties: triclinic, P1¯(#2), a = 12.314(4), b = 15.885(4), c = 10.959(4) Å, = 103.25(2), = 103.60(2), = 109.94(2)°, V = 1843(2) ų, and Z = 2; for -sulfato-bis{(2-acetylpyridine 3-piperidylthiosemicarbazonato)copper(II)}chloroform, [Cu(Acpip)]₂SO₄·CHCl₃: triclinic, P1¯(#2), a = 11.657(1), b = 17.101(2), c = 10.338(1) Å, = 98.51(1), = 109.294(7), = 107.016(9)°, V = 1790.3(4) ų, and Z = 2. The size of the azacyclo ring significantly affects the stereochemistry of these binuclear complexes.     

Synthesis and crystal structure of a cobalt(II) complex with tris(1-pyrazolylmethyl)amine

The synthesis of a cobalt(II) complex of tris(1-pyrazolylmethyl)amine (amtp) is reported. The complex [Co(amtp)Cl](BPh₄) crystallizes in the space group P-1, with a = 8.979(2), b = 19.329(3), c = 20.251(3) Å, = 93.321(2), = 93.685(3), = 98.930(2)°, and Z = 4. The Co(II) atom is nearly tetrahedrally coordinated by three pyrazole N-atoms and one Cl^–. The tertiary amine N-atom of amtp is only weakly coordinated to Co(II) atom at a Co—N(amine) distance of ca 2.40 Å.     

Crystal structure and characterization of 1,2-N,N-disallicydene-phenylamineato nickel(II) complex

A new complex has been synthesized and characterized by elemental analysis, IR, TGA, and single-crystal X-ray analysis. The crystal is orthorhombic and the space group is chiral (P2₁2₁2₁) with a = 6.620(3) Å, b = 17.300(4) Å,, c = 5.450(1) Å,, = 90°, = 90°, = 90°, z = 4. In the crystal lattice, the molecules create a two-dimensional network structure through hydrogen bonds. The C–HO intermolecular hydrogen bonds connect the title complex to form a supermolecular structure.     

Crystal structure of bis(4-dimethylaminopyridinium) tribromocuprate(I) and bis(4-dimethylaminopyridinium) tetrabromocuprate(II)

The synthesis and crystal structures of two copper bromide salts of the 4-dimethylaminopyridinium (4DMAP⁺) cation are reported. The Cu(I) salt, (4DMAP)₂CuBr₃, crystallizes in the monoclinic space group C2/c, with a = 11.724(2), b = 11.055(3), c = 15.763(3) Å, = 107.64(3)°, and Z = 4. It contains isolated planar 4DMAP⁺ cations and trigonal planar CuBr₃ ^2– anions. Small distortions from idealized D _3h symmetry are observed for the anion. For the Cu(II) salt, (4DMAP)₂CuBr₄, a triclinic cell is observed with a = 8.2373(2), b = 9.2428(2), c = 14.4391(1) Å, = 93.760(1), = 94.576(1), = 105.249(1)°, and Z = 2. This compound contains discrete planar 4DMAP⁺ cations and flattened tetrahedral CuBr₄ ^2– anions. Small distortions are observed for ideal D _2d symmetry.     

Crystal structure and physical properties of a ruthenium(II) bipyridine dimethylsulfoxide complex

The complex [Ru(bpy)₂(DMSO)C1]PF₆, where bpy is 2,2-bipyridine and DMSO is dimethylsulfoxide, crystallizes in the triclinic space group P1¯ (#2) with a = 8.873 (2), b = 12.805 (4), c = 12.864 (4) Å, = 97.76(3), = 106.45(2), = 107.88(2); Z = 2, and d _calc = 1.75 mg/m³. The coordination geometry is that of a distorted octahedron with a cis –RuN₄SCl arrangement of coordinating atoms. The four Ru—N distances to the bpy ligands are 2.082(5), 2.092(4), 2.044(4), and 2.078(5) Å. The Ru—Cl distance is 2.421(2) Å and the Ru—S distance to DMSO is 2.260(1) Å. The Ru—N bond distance trans to Cl is the shortest; the Ru—N bond distance trans to S is the longest. The complex is oxidized and reduced reversibly at 1.13 and –1.37 V vs. SSCE, respectively. It displays electronic absorptions at 515, 480 (1.5 × 10⁴), 342 (1.5 × 10⁴), 292 (1.2 × 10⁵), and 240 nm (6.2 × 10⁴) and has a broad emission band centered at 607 nm at 77 K in a 4:1 ethanol/methanol glass. The emission lifetime at room temperature is less than the pulse width of the laser, < 20 ns.     

Schiff bases and their complexes with metal ions. Part II. Structures of N-n-butyl-2-hydroxy-1-naphthaldimine and bis[N-n-pentyl-2-hydroxy-1-naphthaldiminato]nickel(II)

The Schiff base ligand (1), [C₁₅H₁₇NO] crystallizes in the monoclinic space group P2₁/c witha=10.054(3),b=10.313(3), c=13.173(4)Å, =107.42(4)°,V=1303.2(7)ų,Z=4,Dx=1.159 g cm^–3, and (MoK)=0.674 cm^–1. The C2-O[1.23(1)Å] and C3–C4 [1.33(2)Å] bond lengths are short, due to its quinoidal structure. In the Schiff base nickel complex (2), [Ni(C₁₆H₁₈NO)₂] the asymmetric unit is comprised of two half-complexes. It crystallizes in the triclinic space group witha=5.124(3),b=16.227(3),c=16.886(4)Å, =95.47(8), =96.00(1), =90.71(4)°,V=1389.6(9) ų,Z=2,Dx=1.289 g cm^–3, and (MoK) =12.1 cm^–1. The coordination of the Ni(II) ions are square planar with bond angles between 87.9(1) and 92.1(1)°. The Ni–O and Ni–N distances are 1.819(2), 1.922(2) and 1.823(2), 1.914(3)Å in these two complexes.     

Crystal structure of a novel tertiary phosphine coordination complex: dichlorobis(tribenzylphosphine)nickel(II)

The title compound dichlorobis(tribenzylphosphine)nickel(II), Ni[P(CH₂C₆H₅)₃]₂Cl₂, belongs to a type of tertiary phosphine coordination complex, M(PR₃)₂X₂. There are two molecules in the unit cell which do not appear to interact chemically. Both molecules have a trans-square planar configuration with each nickel atom on a center of symmetry. Three benzyl groups are bonded to each phosphorus atom as rotors in a propeller, and the threefold axis is along the P—Ni bond, which has a mean length of 2.23(1) Å. Crystal data: C₄₂H₄₂Cl₂NiP₂, Triclinic, space group , a = 10.4892(15) b = 10.5249(12) c = 19.453(2) Å, = 83.872(8), = 76.839(9), = 62.241(8)°, V = 1850.5(4) ų, Z = 2. There is an intramolecular hydrogen bond between the C3 and C11 atoms.     

Copper(II) complexes 1-phenylpropane-1,2-dione- and benzil bis(3-piperidylthiosemicarbazone): A structural study

The crystal and molecular structure of copper(II) complexes of benzil bis(3-piperidylthiosemicarbazone), [Cu(Bnzpip)] and 1-phenylpropane-1,2-dione bis(3-piperidylthiosemicarbazone), [Cu(Pmpip)] have been determined. [Cu(Bnzpip)] is monoclinic, space group P2₁/n with a = 13.9375(10) Å, b = 11.6621(4) Å, c = 16.4710(10) Å, = 100.667(2)°, and V = 2630.9(3) ų with Z = 4, for d _calc = 1.399 g/cm³. [Cu(Pmpip)] is also monoclinic, space group P2₁/n with a = 11.292(6) Å, b = 10.219(5) Å, c = 20.292(6) Å, = 101.50(3)°, and V = 2295(2) ų with Z = 4, for d _calc = 1.525 g/cm³. Both complexes involve N₂S₂ coordination, are relatively planar except for the phenyl rings and have similar bond distances and angles to copper(II) complexes of other 3-piperidylthiosemicarbazones.     

Crystal structure of chloritopentamminecobalt(III) tetracyanopalladate(II)

The X-ray crystal structure of [(NH₃)₅Co(ClO₂)][Pd(CN)₄]·H₂O consists of two discrete complex ions and a water of hydration. The red crystals are triclinic, P , with lattice parameters a = 7.1992(5), b = 9.4873(7), c = 11.7752(8) Å. = 66.680(1), = 75.784(1), = 82.203(1)°, and Z = 2 giving a cell volume of 715.27(9) ų and a calculated density of 2.043 g/cm³ at 293°. The chlorite ion is O-bonded to the cobalt atom with amine N—Co distances all equal. The chlorite ion is bent with a O—Cl—O angle of 110.8(2)° and the Cl—O distances being 1.601(3) and 1.558(3) Å, the longer value for the O atom also coordinated to Co. The Pd(CN)^–2 ₄ ions are planar, C-coordinated and stack along the x-axis, separated by 3.599(1) Å and alternatively rotated by 29.9(5)°.     

Crystal structure,physical and photophysical properties of a platinum(II) complex coordinated to the biphenyl dianion and cyclooctadiene

The complex, Pt(bph)(COD), where bph is the biphenyl dianion and COD is 1,5-cyclooctadiene, crystallizes in the orthorhombic space groupPbca witha=12.178(4) Å,b=9.693(3) Å andc=25.344(9) Å andZ=8. The Pt–C distances to the olefinic carbon atoms that result from the electron donation of the COD ligand are in the range 2.20(3)–2.27(3) Å and the Pt–C distances to the bonded bph ligand are shorter at 2.01(3)–2.03(2) Å. The lowest energy absorption of the complex is at 383 nm (=1.2×10³). The emission spectrum is structured in fluid solution at room temperature with the emission energy maximum at 537 nm, _cm, and =1.93 s. Temperature dependent emission lifetime measurements result in ak _o value of 2.69×10⁴, a preexponential factor of 2.47×10⁶ and a E₁ value of 324 cm^–1.     

Coordination complexes of 2,6-diarylpyrazines with copper(II) acetate

The coordination chemistry of a series of 2,6- and 2,3-diarylpyrazines with copper(II) acetate is reported. The 2:2 coordination complexes formed between two 2,6-diarylpyrazines and copper(II) acetate are characterized by X-ray crystallography. The structure (2,6-bis(3,5-dimethylphenyl)pyrazine)copper(II) acetate acetonitrile solvate, (C₄₈H₅₂Cu₂N₄O₈) (C₂H₃N) is triclinic, P 1, with a = 7.9685(10), b = 13.1893(16), c = 13.8267(17) Å, = 107.585(3)°, = 103.921(3)° and = 96.759(3)°. The structure of (2-(2,6-dimethylphenyl)-6-(3,5-dimethylphenyl)pyrazine)copper(II) acetate, C₄₈H₅₂Cu₂N₄O₈, is monoclinic, P2₁/c, with a = 8.2196(7), b = 12.5174(11), c = 21.7325(19) Å and = 96.201(2)°.     

Crystal structure of [Cu2(II)(dmpa)2(p-Cl-C6H5COO)2] (Hdmpa = N,N-dimethyl-3-amino-1-propanol)

The copper complex, [Cu₂(II)(dmpa)₂(p-Cl-C₆H₅COO)₂], has been prepared and its structure determined using X-ray crystallography. The dimer is a di-₂-alkoxo complex which is a five-coordinate copper dimer with unsupported alkoxo bridges. The complex crystallizes in the triclinic space group P-1 with a = 11.384(2), b = 14.636(5), c = 9.609(2) Å, = 100.07(2), = 104.33(3), = 72.79(2)°, V = 1471.8(7) ų, and Z = 2. The structure is comprised of discrete binuclear clusters in which the metal atoms are bridged by two alkoxo oxygens of the dmpa^– ligands. The Cu-O and Cu-N distances are in good agreement with those found for other copper(II) aminoalcoholato complexes. The Cu···Cu distance is 2.9765(6) Å. In the crystal, every two dimeric coordination molecules are combined together by the recognition through intermolecular hydrogen-bonding interactions between the apical water molecule and the non-coordinated O atom from the p-chlorobenzoato ligand, forminga tetramer.     

Synthesis and crystal structure of a nickel(II) complex involving imino nitroxide radicals

A new complex of formula [Ni(im2-py)₂(SCN)₂]CH₃OH (im2-py = 2-(2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl) has been synthesized and the crystal structure determined by X-ray diffraction methods. The complex crystallizes in the monoclinic space group P2₁/n with a = 15.525(5) Å, b = 13.405(4) Å, c = 16.167(5) Å, = 113.324(5)°, V = 3089.6(16) ų, and Z = 4. The structure of this complex is mononuclear with the nickel(II) ion octahedrally coordinated and bound to the imino nitroxide radicals through the imino nitrogen atoms. The thiocyanate groups are coordinated to the metal by the nitrogen atoms.     

Two-dimensional nickel(II) tetraaza macrocyclic complex linked by hydrogen bonds

The complex [Ni(L)](PDC) 2H₂O (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[16,4, 0^1.18,0^7.12]docosane; PDC = 3,5-pyrazoledicarboxylate) has been synthesized and characterized by X-ray crystallography. It crystallizes in the monoclinic system P2₁/c with a = 9.739(4) Å, b = 10.491(3) Å, c = 16.884(3) Å, = 97.17(2)°, V = 1711.5(8) ų, Z = 4. The coordination environment around the nickel(II) ion exhibits a slightly distorted square-plane with four secondary amines of the macrocycle. The title compound is interconnected to give a two-dimensional network through the hydrogen-bonding interactions.     

Synthesis and crystal structures of four nickel(II) 1,5-naphthalenedisulfonate compounds

Four nickle(II) 1,5-naphthalenedisulfonate (1,5nds) complexes, namely [Ni(H₂O)₆] (1,5nds) (1), trans-[Ni(en)₂(H₂O)₂](1,5nds)·2H₂O (2), [Ni(tren)(H₂O)₂](1,5nds)·H₂O (3), and [Ni(dien)₂](1,5nds)·2H₂O (4), where en = ethylenediamine, tren = tris(2-aminoethyl)amine, and dien = diethylenetriamine, have been synthesized and structurally characterized. Compound 1 crystallizes in space group P2₁/c, with a = 13.200(2) Å, b = 6.6197(10) Å, c = 9.6001(14) Å, and = 92.005(3)° compound 2 crystallizes in space group C2/c, with a = 15.698(2) Å, b = 13.006(2) Å, c = 12.845(2) Å, and = 119.262(4) Å compound 3 crystallizes in space group P , with a = 8.8971(10) Å, b = 11.5440(13) Å, c = 11.9169(14) Å, = 77.254(2)°, = 74.079(2)°, and = 82.162(2)° compound 4 crystallizes in space group P2₁/c, with a = 10.3600(13) Å, b = 12.5650(16) Å, c = 9.9853(12) Å, and = 103.599(2)°. Compound 1 crystallizes in a typical inorganic–organic layered structure adopted by metal naphthalenesulfonate, while compounds 2–4 crystallize in a hybrid inorganic–organic pattern. Unlike their Cu²⁺ analogue, the sulfonate does not coordinate directly to Ni²⁺. The hydrogen bonds formed between sulfonate and water molecules are the predominant packing forces for all structures. The inherited inversion center of the 1,5nds anion is carried into the crystal structure and results in centrosymmetric crystallization of all compounds.     

Synthesis and X-ray characterization of a polymeric 1:3 complex of copper(II) nitrate with pyrazine

The structure of poly--pyrazine-bis(pyrazine)(dinitrato-O)copper(II), Cu(pyz)₃(NO₃)₂, has been investigated by X-ray diffraction. The compound crystallizes in the triclinic space group with a = 6.8040 (10), b = 7.2860 (10), c = 9.289 (2) Å, = 69.65 (2), = 68.51 (2), = 67.51 (2)°, and Z = 1. The structure consists of linear chains of copper ions bridged by bidentate pyrazine groups, with monodentate terminal pyrazine and nitrate groups completing the distorted octahedral geometry about the copper ions.     

A comparison of the coordination preferences of Zn, Co, and Cd(II) with the heteroscorpionate ligand (2-hydroxy-3-t-butyl-methylphenyl)bis (3,5-dimethylpyrazolyl)methane

Reaction of the Zn, Cd, or Co nitrate salts with the deprotonated ligand (2-hydroxy-3-t-butyl-methylphenyl)bis(3,5-dimethylpyrazolyl)methane (L1O^–) in methanol produced the following complexes: [(L1OH)Zn(NO₃)₂] in two isomorphs, a = 40.983(8) Å, b = 9.571(2) Å, c = 15.667(8) Å, = 90, = 106.38(1), = 90, C2/c, and a = 13.027(3) Å, b = 14.781(4) Å, c = 16.107(3) Å, = 90, = 105.30(1), = 90, P2₁/n; [(L1OH)Cd(pz)(NO₃)₂] a = 14.7476(2) Å, b = 13.5411(2) Å, c = 16.7223(2) Å, = 90, = 110.3840(10), = 90, P2₁/c; and [(L1O)Co(pz)(NO₃)] a = 11.4240(2) Å, b = 13.4498(2) Å, c = 13.8056(2) Å, = 105.2080(10), = 105.8130(10), = 112.7470(10), P . The Zn adopts a pseudotetrahedral four-coordinate geometry where the potentially tridentate ligand is actually bidentate with a protonated and uncoordinated phenoxy arm. The Co complex is pseudooctahedral six-coordinate where the phenoxy arm is deprotonated and coordinated. Finally the Cd complex is seven-coordinate but the metal is not coordinated through the phenoxy group that is again protonated.     

Crystal structure ofcis-[Ru(bpy)2(PPh3)Cl+][ClO 4 − ]·(toluene)·∼0.5(CH2Cl2), a species with two different disordered solvent molecules of crystallization

The complexcis-[Ru(bpy)₂(PPh₃)Cl⁺][ClO ₄ ^– ] (where bpy=2,2-bipyridyl) crystallizes from a solution in toluene/dichloromethane as the toluene-hemi(dichloromethane) solvate in the centrosymmetric space group witha=10.343(2)Å,b=11.823(3)Å,c=18.469(4)Å, =98.90(2)^o, =93.32(2)^o, =101.46(2)^o,V=2177.8(8)ų andZ=2. The structure was refined toR(F)=4.6% for those 4248 reflections above 6(F _o ). The octahedral Ru(II) cation is associated with the bond lengths Ru–Cl=2.424(2)Å, Ru–PPh₃=2.328(1) Å and Ru–N=2.045(5)–2.109(4)Å. Both the cation and the perchlorate anion are ordered. However, the unit cell also contains two disordered toluene molecules (centered about inversion centers at 1, 1/2, 0 and 1/2, 0, 1/2), and a disordered dichloromethane molecule of a partial occupancy (centered about 1/2, 0, 1).     

Synthesis and crystal structure of a terephthalato-bridged copper(II) complex [Cu2(tpt)(bpy)2(H2O)4] [Cu2(tpt)3 (bpy)2(H2O)2]

A terephthalato-bridged copper(II) complex [Cu₂(tpt)(bpy)₂(H₂O)₄][Cu₂(tpt)₃(bpy)₂ (H₂O)₂] (1) (tpt = terephthalate, bpy =; 2,2'-bipyridine) was synthesized by the reaction of Cu(ClO₄)₂ 6H₂O and terephthalic acid in the presence of 2,2'-bipyridine in H₂O solution. Crystal structure of 1 was determined by X-ray diffraction analysis in the triclinic space group P , with a = 10.7327(10) Å, b = 11.1658(11) Å, c = 17.3768(16) Å, = 108.063(2), = 91.064(2), = 116.721(2), V = 1737.5(3) ų, and Z = 2. Both the anion and the countercation in 1 are copper(II) complexes linked by terephthalate bridges in the bis(monodentate) (syn–anti) mode. The anion and the countercation are also linked by two hydrogen bonds between coordinating water molecules and terephthalate ligand.