Synthesis,Properties, and Crystal Structures of Copper(II) Di-(2-picolyl)amine Complexes Containing Inorganic Salts

Abstract These complexes have been characterized by X-ray crystallography, spectroscopic, and cyclic voltammetry. In 1, the copper(II) ion has a distorted square-pyramidal geometry with three nitrogen atoms of the dpa ligand and two oxygen atoms of the nitrate anions. The crystal structure of 2 shows that the copper(II) ions are bridged by tp anion to form a dinuclear complex, in which each copper(II) ion exhibits a distorted square-pyramid with three nitrogen atoms of the dpa ligand, water molecule, and the oxygen atom of the bridging tp ligand. Cyclic voltammetric data indicate that 1 undergoes irreversible one-electron oxidation to the Cu^III and reversible one-electron reduction to the Cu^I, while 2 gives one reversible oxidation and two reversible and irreversible reduced processes. The electronic spectra and redox potentials of the complexes are influenced significantly by the anionic ligands. Graphical Abstract The reaction of [Cu(dpa)Cl₂] with K(NO₃)₂ and Na₂tp yields mononuclear and dinuclear copper(II) complexes [Cu(dpa)(NO₃)₂] (1) and [Cu₂(dpa)₂(H₂O)₂(μ-tp)](tp)·6H₂O (2) (dpa = di-(2-picolyl)amine, tp = terephthalate).      

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.     

Synthesis and crystal structures of nitratocobaltates Na2[Co(NO3)4], K2[Co(NO3)4], and Ag[Co(NO3)3] and potassium nitratonickelate K2[Ni(NO3)4]

The cobalt(II) and nickel(II) nitrate complexes with an island structure (Na₂[Co(NO₃)₄] (I) and K₂[Co(NO₃)₄] (II)] and a chain structure [Ag[Co(NO₃)₃] (III) and K₂[Ni(NO₃)₄] (IV)] are synthesized and investigated using X-ray diffraction. In the anionic complex [Co(NO₃)₄]^2? of the crystal structure of compound I, the Co coordination polyhedron is a twisted tetragonal prism formed by the O atoms of four asymmetric bidentate nitrate groups. In the anion [Co(NO₃)₄]^2? of the crystal structure of compound II, one of the four NO₃ groups is monodentate and the other NO₃ groups are bidentate (the coordination number of the cobalt atom is equal to seven, and the cobalt coordination polyhedron is a monocapped trigonal prism). The crystal structures of compounds III and IV contain infinite chains of the compositions [Co(NO₃)₂(NO₃)_2/2]^? and [Ni(NO₃)₃(NO₃)_2/2]^2?, respectively. In the crystal structure of compound III, seven oxygen atoms of one monodentate and three bidentate nitrate groups form a dodecahedron with an unoccupied vertex of the A type around the Co atom. In the crystal structure of compound IV, the octahedral polyhedron of the Ni atom is formed by five nitrate groups, one of which is terminal bidentate. The data on the structure of Co(II) coordination polyhedra in the known nitratocobaltates are generalized.     

Synthesis and Structure of Trans‐bis(ethanolamine)bis(saccharinato)mercury(II)

Trans‐bis(ethanolamine)bis(saccharinato)mercury(II), [Hg(ea)₂(sac)₂], where ea and sac denote the ethanolamine molecule and the saccharinate anion, respectively, crystallizes in the triclinic space group P (No. 2) with a = 9.4651 (5), b = 10.4365 (5), c = 11.9314 (6) Å, α = 84.402 (1)° β = 78.313 (1)°, γ = 75.307 (1)°, Z = 2, V = 1115.11 (10) ų. The structure consists of isolated [Hg(ea)₂(sac)₂] units in which the Hg(II) ion is octahedrally coordinated by two nitrogen and two oxygen atoms of two neutral ea ligands, and two nitrogen atoms of two sac ligands. The ea acts as a bidentate N‐ and O‐donor ligand and occupies the trans positions of the equatorial plane of the coordination octahedron forming a fivemembered chelate ring, while sac behaves as a monodentate N‐donor ligand occupying the axial positions. The average Hg‐N_sac and Hg‐N_ea bond distances are 2.739 (3) and 2.114 (7) Å, respectively. The crystal exhibits extensive hydrogen bonds between the hydroxyl and amine hydrogen atoms of the ea ligands and the sulfonyl, carbonyl and amine groups of the sac ligands.     

EPR spectra of (L-aspartate)di(2-pyridyl)aminezinc(II) hydrate substitutionally copper(II) doped complex

The [(L-aspartate)di(2-pyridyl)aminezinc(II)]hydrate doped with traces of copper was prepared. Electron paramagnetic resonance spectra of the polycrystalline sample were recorded at room temperature by using the X-band of the EPR spectrometer. The observedg factors for the complex areg _‖=2.258 andg _⊥=2.066. TheA _‖ value is 165.10⁻⁴ cm⁻¹. The crystal and molecular structure of the complex are also reported. The complex crystallizes in the monoclinic system; space groupP2₁ witha=7.2053(11),b=10.447(2),c=10.812(2) Å, β=108.489(14)° andZ=2. The structure can be described in the crystal lattice as polymeric chains.     

EPR spectra of (L-aspartate)di(2-pyridyl)aminezinc(II) hydrate substitutionally copper(II) doped complex

The [(L-aspartate)di(2-pyridyl)aminezinc(II)]hydrate doped with traces of copper was prepared. Electron paramagnetic resonance spectra of the polycrystalline sample were recorded at room temperature by using the X-band of the EPR spectrometer. The observedg factors for the complex areg _‖=2.258 andg _⊥=2.066. TheA _‖ value is 165.10⁻⁴ cm⁻¹. The crystal and molecular structure of the complex are also reported. The complex crystallizes in the monoclinic system; space groupP2₁ witha=7.2053(11),b=10.447(2),c=10.812(2) Å, β=108.489(14)° andZ=2. The structure can be described in the crystal lattice as polymeric chains.     

X-ray crystal structure of trans-bis(monoethanolamine) bis(saccharinato)nickel(II)

The crystal structure of trans-bis(monoethanolamine)bis(saccharinato)nickel(II), [Ni(C₇H₄NO₃S)₂(C₂H₇NO)₂], has been determined from X-ray diffraction data. The metal complex is monoclinic, with a = 11.0555(5), b = 8.9103(4), c = 11.3890(5) Å, = 105.0230(10)°, Z = 2, and space group P2_1/c . The structure consists of individual molecules. Two monoethanolamine molecules and two saccharinate anions coordinate the nickel atom forming a distorted octahedron. The monoethanolamine molecules act as a bidentate ligand and form five-membered trans chelate rings, which constitute the plane of the coordination octahedron, while two saccharinate ions behave as a monodentate ligand occupying the axial positions. Intermolecular hydrogen bonds link the molecules to form a three-dimensional infinite structure.     

Synthesis and crystal structure of an unsymmetric gadolinium(III) cryptate

The synthesis and crystal and molecular structure of [Gd(H₃L)(NO₃)(H₂O)](ClO₄)₂ are reported. The complex crystallizes in the orthorhombic system, space group Pbca with lattice parameters a = 16.974(8), b = 20.010(4), c = 25.202(4) Å, and D_calc = 1.736 mg m^–3, forZ = 8. The coordination number of gadolinium (III) is nine, and its coordination geometry is a distorted monocapped square antiprisms. In the complex, three benzene rings make dihedral angles of 91.7, 92.7, 66.3°, respectively. A water molecule acts as a guest molecule encapsulated in the cryptate.     

Synthesis,crystal and molecular structure of trans‐bis(2‐pyridinepropanol)bis(saccharinato)nickel(II)

Trans‐bis(2‐pyridinepropanol)bis(saccharinato)nickel(II), [Ni(sac)₂(pypr)₂], where sac and pypr are the saccharinate anion and the 2‐pyridinepropanol molecule, respectively, crystallizes in the triclinic space group P (No. 2) with a = 8.1981(8), b = 9.9680(10), c = 10.4956(10) Å, α = 90.740(3)° β = 108.142(3)°, γ = 111.025(3)°, Z = 1, V = 1.537 ų. The structure of the nickel(II) complex consists of neutral molecules in which the nickel(II) ion sits on a center of symmetry and is octahedrally coordinated by two sac ligands, and two neutral pypr ligands. The pypr acts as a bidentate N‐ and O‐donor ligand forming a seven‐membered chelate ring, while sac behaves as a monodentate O‐donor ligand via the carbonyl O atom. The Ni‐N bond distance is 2.1016(15) Å, whereas the Ni‐O_pypr and Ni‐O_sac bond distances are 2.1280(12) and 2.0792(11) Å, respectively. The individual molecules are held together with a strong hydrogen bond between the hydroxyl O atom of pypr and N atom of sac and the C‐H…O type weak hydrogen bonds between some ring hydrogen atoms of pypr and sac, and the carbonyl and sulfonyl O atoms of sac in the neighbouring molecules. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

(Imidazole)(3,3′-trimethylenedinitrilo bis (2-butanone oximate)) copper(II) perchlorate: Synthesis and crystal structure of a five-coordinate copper-protein model complex

The synthesis and crystal structure of the novel pentacoordinated complex [Cu(DOHPN)(IMI-DAZOLE)] (ClO4), (DOHPN=(3,3′-trimethylenedinitrilo bis 2-butanone oxime) are reported. The X-ray crystal structure (space groupP2₁/n, a=11.349(2) Å,b=14.241(3) Å,c= 12.635(3) Å; α=90°, β=100.21 (3)°, γ=90°) shows that the copper(II) ion occupies a distorted square-pyramidal geometry with the imidazole ligand occupying the axial position. The copper(II)-(N)imidazole distance is 2.125(3) Å and the copper(II)-tetraaza plane distance is 0.385/Å. The tetraaza ligand DOHPN adopts a “butterfly-like” geometry with a dihedral angle of 149.69°. The title complex is the first structurally characterized compound of the series [Cu(DOHPN)(axial ligand)]ⁿ⁺ where the axial ligand is a neutral N-heterocycle with known biological relevance. A comparison of the structural parameters with those observed when the axial ligand is H₂O or NCS^? (N-bonded) gives the following series with increasing metal-ligand interaction: H₂O>IMIDAZOLE>NCS^? (N-bonded).     

Synthesis and structure of a hexaazamacrocyclic copper(II) complex with maleato ligand

A hexaazamacrocyclic copper(II) complex Cu(L)(H₂O) (O₂CCH = CHCO₂)⋅H₂O (1) (L = 3,10-bis(2-hydroxyethyl)-1,3,5,8,10,12-hexaazacyclotetradecane) was prepared and structurally characterized by a combination of analytical, spectroscopic, and crystallographic methods. In complex 1, the coordination geometry about the copper(II) ion is six-coordinate with four equatorial nitrogen atoms from the macrocycle and two oxygen atoms from the axial maleato and aqua ligands. In 1, the one end of the maleato ligand coordinates to the central copper atom, while the other end is not bonded. The macrocycle and the axial ligands are highly involved in multiple types of hydrogen bonding interactions, resulting in the stabilization of the maleato ligand as a “coordinated ligand counter anion.”     

A novel two-dimensional zinc(II) complex of a di-N-carboxymethylated tetraaza macrocycle linked by hydrogen-bonds

The complex [ZnL]·10H₂O (L = 2,13-bis(2-carboxymethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) has been synthesized and structurally characterized. It crystallizes in the monoclinic system, space group P2₁/c with a = 10.159(1), b = 10.066(3), c = 17.268(2) Å, = 102.92(1)°, V = 1721.0(5) ų, and Z = 2. The crystal structure reveals an axially elongated octahedral geometry with bonds from the zinc(II) ion to the secondary and tertiary amines of the macrocycle and two oxygen atoms of the pendant carboxymethyl groups. The molecules of the zinc(II) complex are connected into a two-dimensional chain via hydrogen bonds.     

Synthesis and X-ray crystal structure of a complex formed by reaction of 1,2-bis(2′-pyridylethynyl)benzene and mercury(II) chloride

The X-ray crystal structure of the complex formed between 1,2-bis(2′-pyridylethynyl) benzene and mercuric(II) chloride is described. The complex (C₄₀H₂₄Cl₆Hg₃N₄) crystallized in the triclinic space group P-1 with a=9.0414(6), b=9.4631(7), c=12.1134(9) ?, α=97.4680(10), β=94.8130(10), γ=105.4700(10)°. The structure reveals that the ligand is distorted from planarity to accommodate the mercury cation and a third mercuric chloride moiety is held between two ligand-mercury coordination complexes. The central mercury cation has octahedral coordination geometry surrounded by six chlorides while the other two mercury cations have distorted tetrahedral geometry each coordinated by two pyridyl nitrogen atoms and two chlorides.     

Molecular assembly in an inclusion crystal of tris(2-benzimidazylmethyl)amine with 4-nitrobenzoic acid

A 1:2 inclusion compound of tris(2-benzimidazylmethyl)amine with 4-nitrobenzoic acid [(C₂₄H₂₁N₇) · (C₇H₅NO₂)₂] has been prepared and the molecular assembly in solid state has been determined by X-ray crystal structural analysis. The crystal structure (C 2/c, a = 25.488(5), b = 13.304(3), c = 21.479(4) Å, = 93.35 (3)°, Z = 8, R = 0.065) consists of discrete dimeric inclusion compounds joined together by N(5)...N(6) intermolecular hydrogen bonds between pairs of centrosymmetrically related benzimidazole rings of the hosts. There are two types of guest molecules in the crystal, one is incorporated within the cavity of the host via three intramolecular N—H···O hydrogen bonds while the other is situated outside the cavity and connected with the host through one O—H···N hydrogen bond. The – stacking interactions between guests and benzimidazole rings result in one-dimensional columns. The aromatic face–face interactions between neighbouring columns facilitate the assembly of those columns into two-dimensional layers.     

Influence of counter-anion on the coordination geometry of manganese(II) complexes with methyl-2-pyrazinecarboximidate ligand

Two new complexes of [Mn(2-MPyzCI)₂Cl₂].H²O (1) and [Mn(2-MPyzCI)₂(H₂O)₂](NO₃)₂ (2) were synthesized from the reaction of MnX₂.4H₂O (X=Cl^? and NO₃^?) with 2-cyanopyrazine in methanolic solution. The chelating methyl pyrazine-2-carboximidate (2-MPyzCI) ligand is formed via the methanolysis of 2-cyanopyrazine. Although coordination environment around manganes(II) ions is similar, but these complexes are different in geometrical position of 2-MPyzCI ligands. As both compounds are synthesized under the same reaction conditions, the only difference between these two complexes are counter ions and changing of geometrical position of ligands can be considered as a result of influence of the counter-anions on the molecular structures.     

Synthesis and Characterization of [(1-benzylpyrazole) [<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-bis(2-aminoethyl)-1,2-ethanediamine]copper(II)] Diperchlorate,a Structure with a Sterically Strained,Distorted-Trigonal-Bipyramidal Cation

Abstract  The synthesis, characterization, and molecular structure of the title compound, [(1-benzylpyrazole)[N,N-bis(2-aminoethyl)-1,2-ethanediamine]copper(II)] diperchlorate, [(nbp)(tren)Cu(II)](ClO₄)₂, 2  · 2ClO₄, is reported. The salt crystallized in the monoclinic space group P2₁/n with a = 10.1453(5) ?, b = 17.5250(8) ?, c = 13.6021(6) ?, β = 100.737(19)° and V = 2376.06(19) ?³ with Z = 4. The structure contains copper(II) (nbp)(tren) cations, each with a distorted-trigonal-bipyramidal CuN₅ coordination geometry, separated by perchlorate anions. The cations exhibit steric strain associated primarily with close contacts between the methylene protons of the nbp ligand and one of the amine groups of the tren ligand. The strain has a noticeable effect on the coordination geometry and certain physical properties of the complex. Graphical Abstract  In the title structure, steric strain in the (nbp)(tren)Cu(II) cations, associated with close contacts between protons of the nbp ligand and two of the amine groups of the tren ligand (dashed lines in the figure below) affects certain physical properties of the cation and is consistent with an anomalously long Cu(II)–N(pyrazole) distance (Cu–N41) and an unusually large axial–equatorial angle, N41–Cu–N12.      

Isolation and Crystal Structure of [Cu(L1)(O2CH)](ClO4)?·?H2O: Hydrolysis of DMF ( N , N -Dimethylformamide) by a Copper(II) Tetraazamacrocycle

The tetraazamacrocyclic copper(II) complex, [Cu(L)](ClO₄)₂ (L = 3,14-dimethyl-2,6,13,17-tetraazatricyclo[14.4.0^1.18.0^7.12]docosane), hydrolyzes DMF at room temperature. The formate anion which is one of the hydrolyzed species of DMF coordinates to the copper(II) ion to form [Cu(L1)(O₂CH)](ClO₄) · H₂O (1). The crystals of the complex 1 were isolated and structurally characterized by a combination of analytical, spectroscopic, and crystallographic methods. In 1, the macrocyclic ligand contains two trans fused cyclohexane rings, and the coordination geometry about the copper(II) ion adopts a square pyramid with four equatorial nitrogen atoms from the macrocycle and an oxygen atom from the formato ligand with an uncoordinated perchlorate ion.     

Synthesis, properties, and X-ray structure of [Cu(dpa)Cl2] (dpa = di-(2-picolyl)amine)

The mono(dpa)copper(II) complex [Cu(dpa)Cl₂] (1) (dpa = di-(2-picolyl)amine) has been synthesized and structurally characterized. It crystallizes in the monoclinic system P2₁/n with a = 8.155(1), b = 12.560(1), c = 12.817(2) Å, = 91.64(2)°, V = 1312.3(2) ų, Z = 4. The copper atom is coordinated by three nitrogen atoms from the dpa ligand and two chlorides in a distorted square-pyramidal environment. Cyclic voltammetric data show that 1 undergoes the reversible one-electron oxidation to the Cu(III) and the reversible one-electron reduction to the Cu(I) state.     

Synthesis and characterization of a lead(II) complex [Pb(phen)(H<Subscript>2</Subscript>O)(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>] (phen = 1,10-phenanthroline)

The monomeric lead(II) complex, [Pb(phen)(H₂O)(NO₃)₂] was prepared by a hydrothermal reaction of Pb(NO₃)₂, nitrilotriacetic acid, NaOH, 1,10-phenanthroline, and H₂O. The structure was determined by X-ray crystallography. It crystallizes in monoclinic P2(1)/n space group with the crystal cell parameters of a = 6.3568(6), b = 20.2345(19), c = 11.2722(9) Å, β = 98.337(4)^°, V = 1434.6(2) ų, and Z = 4. The crystal X-ray analysis shows that the lead atom is six-coordinated by two N atoms of phen ligand, three oxygen atoms of nitrate anions and one water molecule. Owing to the presence of a lone pair of electrons of lead atom, a significant gap occurs in the coordination geometry around Pb ion. A 3D architecture is formed through the strong hydrogen bonding and π–π stacking interactions.     

A new assembly containing [Fe(dien)2]2+ and [Ni(CN)4]2− ions

A tetracyanometallate with complex dien cation [Fe(dien)₂][Ni(CN)₄] (1) (dien = diethylenetriamine), has been prepared and characterized by IR, UV-Vis and ESR spectroscopies. Single crystal X-ray analysis reveals that the compound assumes a ‘zero-dimensional’ structure in which one iron(II) ion is coordinated by six nitrogen atoms of the two dien ligands and the [Ni(CN)₄]²⁻ anion remains outside the coordination sphere. The six-coordinate iron(II) centres display a distorted octahedral arrangement.