Synthesis and Crystal Structure of [Cu3（dmpzm）4（μ-1, 3-dca）2（dca）4]·2H2O （dmpzm = 1,1＇-Methylenebis- （3,5-dimethyl-1H-pyrazole）, dca = dicyanamide）

The title compound, [Cu3（dmpzm）4（μ-1,3-dca）2（dca）4]·2H2O （dmpzm = 1,1＇-methylenebis（3,5-dimethyl-lH-pyrazole）, dca = dicyanamide） 1·2H2O, was synthesized via the reaction of CuCl2·2H2O with dmpzm and Na（dca）, and characterized by elemental analysis and IR spectra. 1·2H2O crystallizes in the monoclinic system, space group C2/m with a = 13.578（3）, b = 16.769（3）, c = 14.769（3） A, β = 104.10（3）° V = 3261.4（11） A^3, Z = 2, Dc = 1.466 g/cm^3, T = 153（2） K, C56H68N34O2Cu3, Mr = 1440.09, F（000） = 1490,μ（MoKa） = 1.040 mm^-1, S = 1.150, R = 0.0553 and wR = 0.1123 for 2744 observed reflections with I 〉 2σ（I）. The central copper atom is chelated by two dmpzm ligands and coordinated by two bridging dca anions, forming a slightly distorted octahedral geometry. The two external copper atoms adopt a square-pyramidal coordination geometry, coordinated by one chelating dmpzm ligand and one bridging and two terminal dca anions. Two intermolecular hydrogen bonding interactions result in the formation of a 2D （4,4） hydrogen-bonded network.     

Synthesis and Crystal Structure of [Cu3(dmpzm)4(μ-1,3-dca)2(dca)4]·2H2O (dmpzm = 1,1·-Methylenebis-(3,5-dimethyl-1H-pyrazole), dca = dicyanamide)

The title compound, [Cu3(dmpzm)4(μ-1,3-dca)2(dca)4]·2H2O (dmpzm = 1,1'-methyle- nebis(3,5-dimethyl-1H-pyrazole), dca = dicyanamide) 1·2H2O, was synthesized via the reaction of CuCl2·2H2O with dmpzm and Na(dca), and characterized by elemental analysis and IR spectra. 1·2H2O crystallizes in the monoclinic system, space group C2/m with a = 13.578(3), b = 16.769(3), c = 14.769(3)(A),β=104.10(3)°, V = 3261.4(11)(A)3, Z = 2, Dc = 1.466 g/cm3, T = 153(2) K, C56H68N34O2Cu3, Mr = 1440.09, F(000) = 1490, μ(MoKα) = 1.040 mm(1, S = 1.150, R = 0.0553 and wR = 0.1123 for 2744 observed reflections with I > 2σ(I). The central copper atom is chelated by two dmpzm ligands and coordinated by two bridging dca anions, forming a slightly distorted octahedral geometry. The two external copper atoms adopt a square-pyramidal coordination geometry, coor- dinated by one chelating dmpzm ligand and one bridging and two terminal dca anions. Two inter- molecular hydrogen bonding interactions result in the formation of a 2D (4,4) hydrogen-bonded network.     

Syntheses and Crystal Structures of Two Nickel（Ⅱ） Complexes [Ni（dmpzm）2（L）]Cl·nH2O（L = HCO2, OAc; n = 2, 3; dmpzm = 1,1＇-Methylenebis（3,5-dimethyl-1H-pyrazole））

Reactions of NiCl2-6H2O with dmpzm and formic or acetic acid at PH = 7 produced the two title compounds, [Ni（dmpzm）2（HCO2）]Cl·2H2O 1 and [Ni（dmpzm）2（OAc）]C2·H2O 2 （dmpzm = 1,1 ＇-methylenebis（3,5-dimethyl-lH-pyrazole））. 1 and 2 were characterized by elemental analysis, IR spectra, and thermogravimetric analysis. 1 crystallizes in the orthorhombic system, space group Pcca with a = 18.700（2）, b = 8.6843（9）, c = 18.098（2）A, V= 2939.1（5）A^3, Z = 4, Dc = 1.319 g/cm^3, T = 193 K, C23H37CINsNiO4, Mr = 583.75, F（000） = 1232, p（MoKa） = 0.792 cm^-1, S = 1.079, R = 0.0772 and wR = 0.1958 for 2265 observed reflections with I〉 2σ（I）. 2 crystallizes in the orthorhombic system, space group Pcca with a = 17.011（3）, b = 18.630（4）, c = 19.300（4）A, V = 6117（2）A^3, Z = 8, Dc = 1.337 g/cm^3, T= 193（2） K, C24H41C1N8NiO5, Mr = 615.79, F（000） = 2608, μ（MoKa） = 0.768 cm^-1, S = 1.059, R = 0.0518 and wR = 0.1109 for 5124 observed reflections with I 〉 2σ（I）. The Ni atoms in 1 or 2 are chelated by two dmpzm ligands and one formate or acetate anion, forming slightly distorted octahedral geometries. In the crystals of 1 or 2, intermolecular hydrogen bonding interactions result in the formation of 2D hydrogen-bonded frameworks.     

Hydrothermal Synthesis and Crystal Structure of a Novel Dinuclear Co（ Ⅱ ） Complex： [Co2（2,2＇-bpy）2（μ-L）e（L）2（μ-H2O）] （HL = 4-Chlorobenzoic Acid）

ABSTRACT A new 4-chlorobenzoic acid bridge Co（Ⅱ ） complex [[Co2（2,2＇-bpy）2（μ-L）e（L）2（μ-H2O）] （HL = 4-chlorobenzoic acid） has been obtained by hydrothermal synthesis, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group C2/c with a = 22.537（5）, b = 16.212（3）, c = 15.306（3） A, β= 124.37（3）°, V= 4616.1（16）A3, Mr = 1070.45, Dc = 1.540 g/cm3, Z = 4, p = 1.012 mm-1, F（000） = 2176, the final R = 0.0338 and wR= 0.0810. The title complex is composed of dinuclear [Co2（2,2＇-bpy）2（μ-L）2（L）2（μ-HaO）] molecules. Each Co（Ⅱ ） atom is coordinated by two nitrogen atoms from one 2,2’-bipyridine ligand, three oxygen atoms from three 4-chlorobenzoic ions and another oxygen atom from one water molecule. The two Co（Ⅱ） atoms are connected by two 4-chlorobenzoic ions and one bridged water molecule. The dinuclear molecules are interlinked by hydrogen bond and π-π stacking interactions into a three-dimensional supramolecular network.     

Synthesis and Crystal Structure of a Novel Tetranuclear Zinc（Ⅱ） Coordination Polymer [Zn4（o-bda）4（p-pbim）4]n

A novel tetranuclear zinc（H） coordination polymer [Zn4（o-bda）a（p-pbim）4]n 1 （p-pbim = 4-pyridylbenzimidazole, o-bda2 = o-phenylenediacetic acid dianion） has been synthesized by a hydrothermal method and characterized by elemental analysis, IR and X-ray singlecrystal diffraction. The title complex crystallizes in monoclinic, space group of P21/n with α = 14.231（1）, b = 16.257（1）, c = 16.794（1） ]k, β = 100.26（1）°, V = 3823.1（2）A3, Z = 8, Dc = 1.573 g/cm^3,β = 1.321 mm^-1, F（000） = 1856, R = 0.0420 and wR = 0.111. The Zn（1） atom assumes a distorted trigonal bipyramidal geometry, involving three carboxyl O atoms from two different o-bda ligands and two N atoms from two p-pbim ligands. The Zn（2） atom is coordinated by two oxygens from two distinct bda2- anions and two nitrogen atoms from two p-pbim ligands to form a distorted tetrahedral geometry. The Zn（Ⅱ） atoms are alternately interlinked by o-bda ligands in bis-monodentate or chelating-bidentate and monodentate modes into one-dimensional undulate chains along axis c with the adjacent Zn…Zn distances of 8.32 and 8.47 A. Such neighboring chains are further extended into a 1D bi-chain structure with two different subrings A and B, which are 32- and 14-membered rings through interchain p-pbim ligands. There exists a 2D supramolecular network linked by intermolecular hydrogen-bonding interactions between the uncoordinated carboxylate 0（4） atom or coordinated carboxylate 0（7） atom and the uncoordinated imidazolyl N（2） and N（5） atoms with the O...N distances to be 2.695 and 2.807A.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of a New Dinuclear Copper Complex [C2H6ON]2[Cu2Cl2（μ-CH3COO）4]

The hydrothermal reaction of copper chloride dihydrate and 5,5-dimethyl-imidazolidine,-2,4-dione with a mole ratio of 1：1 in acetonitrile resulted in the formation of a new acetate-bridged dinuclear copper complex, [C2H6ON]2[Cu2Cl2（μ-CH3COO）4]. Protonated acetamide in eaolie form and acetic acid were yielded by the hydrolysis of acetonitrile under hydrothennal condition. The rifle complex （C12H24Cl2Cu2N2O10） was characterized by X-ray single-crystal diffraction, IR spectrum, elemental and electrochemical analysis. It crystallizes in the monoclinic system, space group P21/c with a = 8.298004）, b = 14.358（2）, c = 12.0010（2） A^°, β= 130.620（3）°, V = 1085.3（2） A^°^3, Dc = 1.696 g/cm^3, 34, = 554.31, Z = 2, F（000） = 564 and μ = 2.254 mm^-1. The crystal structure consists of a tetraacetate-bridging dinulcear copper complex anion [Cu2Cl2（μ-CH3COO）4]^2-, with the chlorine anions in the axial positions, and two protonated acetamide cations [C2H6ON]^＋, which were connected through hydrogen bonds to form a three-dimensional infinite network.     

Synthesis and Crystal Structure of a New Complex {[ Co^ⅢL2]·[Co^Ⅱ（H2O）6]0.6·2.25H2O }4 （H2L = N-（2-Hydroxyphenyl）salicylidenimine）

The reaction of Co（OAc）2·4H2O with the Schiff base H2L in a methanol solution affords the red crystals of { [Co^ⅢL2]·[Co^Ⅱ（H2O）6]0.5·2.25H2O}4 1 （H2L = N-（2-hydroxyphenyl） salicylidenimine）. The molecular and crystal structures were determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group P21/n, C104Hi14Co6NaO37, Mr = 2421.61, a = 10.625（3）, b = 16.335（4）, c = 15.265（4）A^°, β = 102.990（4）°, V= 2581.6（11）A^°^3, Z = 1, Dc= 1.558 g/cm^3,μ = 1.034 mm^-1, F（000） = 1252, R = 0.0414 and wR = 0.1167 for 5889 reflections. The Co（HI） atom is six-coordinated by two nitrogen atoms and four oxygen atoms of two tridentate L ligands. The abundant hydrogen bonding interactions extend the complex into a one-dimensional supra- molecular framework. The uncoordinated water molecules act as space-fillers and consolidate the whole architecture through the hydrogen bonding interactions.     

Synthesis and Crystal Structure of catena-Poly[[[2,4-dibromo-6-[（3-dimethylaminopropylimino）-methyl]phenolato]copper（II）]-μ-azido]

A novel end-to-end azido-bridged polynuclear Schiff-base copper（II） complex, [Cu（C12H15Br2N2O）（N3）]n, was prepared and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The crystal belongs to the orthorhombic system, space group Pbcn with a = 24.588（5）, b = 10.377（2）, c = 13.022（3） A, V= 3322.6（12） A^3, Z = 8, Dc = 1.874 g/cm^3, Mr = 468.65, λ（MoKa） = 0.71073 A,μ = 6.130 mm^-1, F（000） = 1832, R = 0.0637 and wR = 0.1176. The Cu atom in the complex is five-coordinated in a square pyramidal geometry by three donor atoms of the Schiff-base ligand, and two N atoms from two bridging azide ligands. The [2,4-dibromo-6-[（3-dimethylaminopropylimino）methyl]phenolato]copper（II） units are linked by the bridging azide ligands, giving zigzag polymeric chains with backbones of the [--Cu-N-N-N--Cu]n type running along the b axis.     

Synthesis and Structure of a Novel Supramolecular Compound E Co（ 2,2＇-bipy） （ H20 ） 4] E trans-1,4-chdc ] and Separation of Isomer of 1,4-Cyclohexanedicarboxylic Acid

A supramolecular compound, [ Co（2,2＇-bipy） （ H2O）4 ] [ trans-1,4-chdc ] （ compound 1 ） （ 2,2＇-bipy = 2,2＇- bipyridine, 1,4-chdcH2 = 1,4-cyclohexanedicarboxylic acid）, was synthesized and characterized by single-crystal Xray diffraction analysis, IR spectrometry, TG analysis, and elemental analyses. Single-crystal X-ray diffraction analysis revealed that [ Co（ 2,2＇-bipy） （ H2O）4 ]^2＋ units and adjacent 1,4-chdc^2- formed a single layer by hydrogen bonding and electrostatic interactions along the ac-plane, and two symmetry-related single layers interacted with each other by hydrogen bonding, resulting in a double layer, which further formed a 3-D structure by π-π stacking. The most attractive structural feature of compound 1 is that 1,4-chdc2- possesses only tram-conformation although there are both c/s- and tram-conformations in the raw material.     

Synthesis,Crystal Structure and Biological Activity of a Novel Complex： Co（L）2（CH3OH）2Cl2 （L = 3-（1,2,4-Triazole-yl）-6-chloro-pyridazine）

The title compound, Co（L）2（CH3OH）2Cl2 （L = 3-（1,2,4-triazole-yl）-6-chloro-pyridazine） 1, has been synthesized and its crystal structure has been determined by X-ray analysis. Complex 1 crystallizes in the triclinic system, space group P1 with a = 6.018（3）, b = 9.832（5）, c = 9.921（5）A, a = 78.270（8）, β = 74.550（8）, γ = 83.807（8）°, V = 553.1（5）A^3, Z = 1, C14H16Cl4CoN10O2, Mr = 557.10, Dc = 1.673 g/cm^3, F（000） = 281,μ（MoKα） = 1.293 mm^-1, the final R = 0.0453 and wR = 0.1181 for 1539 observed reflections with I 〉 2σ（I）. The Co（II） ion is in a distorted centrosymmetric six-coordinate octahedral environment with two Ntriazole, two Omethanol and two Cl atoms. Via hydrogen bonds the configuration of 1 has been extended into 1D chains which are developed to 2D layers via π-π sticking action, and these layers are further extended into a 3D network by hydrogen bonds. The antibacterial activity of the title compound has been detected, and the results show that the ligands and cobalt（II） complex exhibit certain fungicidal activity against several bacteria. Furthermore, the spectral properties of the title compound have been also studied and discussed.     

Synthesis,Structure and Magnetic Properties of Two Cobalt(II) Dicyanamide (dca) Complexes with Heterocyclic Nitrogen Donors Tetra(2‐pyridyl)pyrazine (tppz) and 2,4,6‐Tri(2‐pyridyl)‐1,3,5‐triazine (tptz): [Co2(tppz)(dca)4]·CH3CN and [Co(tptz)(dca)(H2O)](dca)

Two new transition metal dicyanamide complexes [Co₂(tppz)(dca)₄]·CH₃CN ( 1 ) [tppz=tetra(2‐pyridyl)pyrazine, dca=dicyanamide] and [Co(tptz)(dca)(H₂O)](dca) ( 2 ) [tptz=2,4,6‐tri(2‐pyridyl)‐1,3,5‐triazine] were synthesized and characterized by single crystal X‐ray diffraction analysis. In 1 each cobalt(II) atom is coordinated to three dca anions and one tppz molecule to form a distorted octahedral geometry, the neigbour two cobalt(II) atoms are bridged by one tppz ligand to form a dimer, then the cobalt(II) atoms in each dimer are joined together to form a ladder chain structure. In 2 the coordination geometry around the central metal is also distorted octahedral, each cobalt(II) atom is coordinated by two dca anions, one tptz molecule and one water ligand to form a cationic part, and the cationic part is linked with the free dca anions via the electrostatic attraction to give an infinite chain structure. Magnetic susceptibility measurement in the range of 2–300 K indicates that there are antiferromagnetic couplings between adjacent metal ions in 1 (T>29 K, (=?9.78 K, C=4.92 cm³·K·mol^?1) and ferromagnetic couplings in 2 (T>150 K, (=7.97 K, C=2.59 cm³·K·mol^?1) respectively.     

Syntheses,Structures and Electrochemistry Properties of Two Dicyanamide Manganese(III) Complexes [Mn(5‐Brsalen)(dca)]·CH3OH and [Mn(3‐Meosalphen)(dca)(H2O)]

Two manganese(III)‐dicyanamide compounds, [Mn(5‐Brsalen)(dca)] · CH₃OH ( 1 ) and [Mn(3‐Meosalphen)(dca)(H₂O)] ( 2 ) (dca = dicyanamide anion, [N(CN)₂]^–), were synthesized and characterized by elemental analysis, IR spectroscopy, single‐crystal X‐ray structure analysis, and cyclic voltammetry. The structure of complex 1 is an infinite zigzag chain of hexacoordinate Mn^III ions, in which the adjacent manganese atoms are connected by dca in μ_1,5‐bridging mode. The molecular structure of complex 2 consists of a hexacoordinate Mn^III atom, which generates a slightly distorted octahedral arrangement, and a dimer structure is formed by intermolecular hydrogen bonding interactions. The electrochemical properties of the two complexes were measured by cyclic voltammetry.     

Syntheses and Structures of two 1‐D Complexes, [Co(dmf)2(NCNCN)2] and [Cu(bipy)(NCNCN)]ClO4 with Bridging Dicyanamide Ligands

Two novel dicyanamide complexes [Co(dmf)₂(NCNCN)₂] ( 1 ) and [Cu(bipy)(NCNCN)]ClO₄ ( 2 ) have been synthesized and structurally characterized. 1 crystallizes in the monoclinic space group C2 with a = 13.568(6)Å, b = 7.403(3)Å, c = 8.118(3)Å and Z = 2, whereas 2 crystallizes in the monoclinic system, Cc group, a = 14.270(7)Å, b = 9.143(5)Å, c = 12.371(1) Å, β = 118.612(7)°, and Z = 4. According to X‐ray crystallographic studies, in complex 1 each Co^II ion is six‐coordinated with four nitrogen atoms from four μ_{1, 5}‐dca (dca = dicyanamide) ligands and two oxygen atoms from two dmf ligands to form distorted octahedra. 1 forms a 1‐D network bridged via μ_{1, 5}‐dca. 2 consists of a uniform Cu(NCNCN)Cu chain, each Cu^II ion is octahedrally coordinated with four nitrogen atoms from two μ_{1, 5}‐dca ligands and one bipy ligand and two oxygen atoms from two ClO₄^— ions. The octahedral Cu^II ion shows a significant Jahn‐Teller distortion, with two axial oxygen atoms considerably farther from the copper than the four equatorial nitrogens.     

A novel two‐dimensional network cadmium(II) coordination polymer containing one 1,4‐bis­(1,2,4‐triazol‐1‐yl)butane and double dicyanamide bridges

In the crystal structure of the title complex, poly[μ‐1,4‐bis­(1,2,4‐triazol‐1‐yl)butane‐di‐μ‐1,5‐dicyanamido‐cadmium(II)], [Cd(C₂N₃)₂(C₈H₁₂N₆)]_n or [Cd(dca)₂(btb)]_n, where dca is dicyanamide and btb is 1,4‐bis­(1,2,4‐triazol‐1‐yl)butane, each Cd^II atom occupies a center of symmetry and is in a six‐coordinated distorted octa­hedral environment. Four N atoms from four dca ligands fill the equatorial positions, and two N atoms from two btb ligands occupy the axial positions. The dca ligands adopt an end‐to‐end coordination mode and link the Cd^II atoms to form a 12‐membered Cd(dca)₂Cd ring, and neighboring rings extend along the b axis to form a [Cd(dca)₂]_n chain. The btb ligands, acting as bridging bidentate ligands, link the Cd^II atoms of adjacent one‐dimensional [Cd(dca)₂]_n chains, forming a rhombic two‐dimensional network.     

Heteropolynuclear Sodium(I) Lead(II) Complex: Crystal and Molecular Structure of a Novel 3‐D Polymer, [(en)Pb(μ3‐ONO)2Na(μ3‐ONO)2Na(μ‐O2ClO2)Na]n

A novel 3D polymeric heteropolynuclear sodium(I) lead(II) complex containing different ligands, [NaPb(ClO₄)(en)(NO₂)₂] was synthesized and characterized by elemental analysis and IR, and ¹H‐, ¹³C‐, and ²⁰⁷Pb‐NMR spectroscopy. The single‐crystal X‐ray data of [NaPb(ClO₄)(en)(NO₂)₂]_n established that the complex is a three‐dimensional polymer, [(en)Pb(μ₃‐ONO)₂Na(μ₃‐ONO)₂Na(μ‐O₂ClO₂)Na]_n. The Pb and Na atoms have four‐ and eight‐coordinate geometry, respectively. The lone pair of electrons at the Pb^II atom is ‘stereochemically active’.     

The topotactic dehydration of monoclinic {[Co(pht)(bpy)(H2O)2]·2H2O}n into orthorhombic [Co(pht)(bpy)(H2O)2]n (pht is phthalate and bpy is 4,4′‐bipyridine)

Controlled heating of single crystals of the previously reported [Köferstein & Robl (2007). Z. Anorg. Allg. Chem. 633 , 1127–1130] dihydrate {[Co(pht)(bpy)(H₂O)₂]·2H₂O}_n, (II) [where pht is phthalate (C₈H₄O₄) and bpy is 4,4′‐bipyridine (C₁₀H₈N₂)], produced a topotactic transformation into an unreported diaqua anhydrate, namely poly[diaqua(μ₂‐benzene‐1,2‐dicarboxylato‐κ²O¹:O²)(μ₂‐4,4′‐bipyridine‐κ²N:N′)cobalt(II)], [Co(C₈H₄O₄)(C₁₀H₈N₂)(H₂O)₂]_n, (IIa). The structural change consists of the loss of the two solvent water molecules linking the original two‐dimensional covalent substructures which are the `main frame' of the monoclinic P2/n hydrate (strictly preserved during the transformation), with further reaccommodation of the latter. The anhydrate organizes itself in the orthorhombic system (space group Pmn2<sub>1</sub>) in a disordered fashion, where the space‐group‐symmetry restrictions are achieved only in a statistical sense, with mirror‐related two‐dimensional planar substructures, mirrored in a plane perpendicular to [100]. Thus, the asymmetric unit in the refined model is composed of two superimposed mirror‐related `ghosts' of half‐occupancy each. Similarities and differences with the parent dihydrate and some other related structures in the literature are discussed.     

The infinite double‐stranded chain polymer catena‐poly­[[bis­(dicyan­amido)­zinc(II)]‐di‐μ‐1,2‐bis(1,2,4‐triazol‐1‐yl)­ethane‐κ4N4:N4′]

The coordination geometry of the Zn^II atom in the title complex, [Zn(C₂N₃)₂(C₆H₈N₆)₂]_n or [Zn(dca)₂(bte)₂]_n, where bte is μ‐1,2‐bis(1,2,4‐triazol‐1‐yl)­ethane and dca is dicyan­amide, is distorted compressed octahedral, in which the Zn^II atom lies on an inversion center and coordinates four N atoms from the triazole rings of four symmetry‐related bte ligands and two N atoms from two symmetry‐related monodentate dca ligands. The structure is polymeric, with 18‐membered spiro‐fused rings extending in the b direction and each 18‐membered ring involving two inversion‐related bte mol­ecules.     

catena‐Poly­[[dicyan­amido(1,10‐phen­anthroline)copper(II)]‐μ‐dicyan­amido]

The title compound, [Cu(C₂N₃)₂(C₁₂H₈N₂)]_n, has a sheet‐like structure, built by [Cu(phen)(dca)₂]_n (phen is 1,10‐phenanthroline and dca is dicyan­amide) chains which are interconnected by secondary long Cu—N bonds between the chains. The Cu²⁺ ion is in a distorted tetragonal bipyramidal (5 + 1) coordination environment. The sheets stack into the three‐dimensional crystal structure through aromatic interactions between the coordinated phen ligands of adjacent sheets.     

Self‐assembly properties of Salamo‐type trinuclear Cu(II) and Co(II) complexes based on the regulation of H+/OHˉ

A novel naphthalenediol‐based bis(salamo)‐type tetraoxime compound (H₄L) was designed and synthesized. Two new supramolecular complexes, [Cu₃(L)(μ‐OAc)₂] and [Co₃(L)(μ‐OAc)₂(MeOH)₂]·4CHCl₃ were synthesized by the reaction of H₄L with Cu(II) acetate dihydrate and Co(II) acetate dihydrate, respectively, and were characterized by elemental analyses and X‐ray crystallography. In the Cu(II) complex, Cu1 and Cu2 atoms located in the N₂O₂ sites, and are both penta‐coordinated, and Cu3 atom is also penta‐coordinated by five oxygen atoms. All the three Cu(II) atoms have geometries of slightly distorted tetragonal pyramid. In the Co(II) complex, Co1 and Co3 atoms located in the N₂O₂ sites, and are both penta‐coordinated with geometries of slightly distorted triangular bipyramid and distorted tetragonal pyramid, respectively, while Co2 atom is hexa‐coordinated by six oxygen atoms with a geometry of slightly distorted octahedron. These self‐assembling complexes form different dimensional supramolecular structures through inter‐ and intra‐molecular hydrogen bonds. The coordination bond cleavages of the two complexes have occurred upon the addition of the H⁺, and have reformed again via the neutralization effect of the OH^?. The changes of the two complexes response to the H⁺/OH^? have observed in the UV–Vis and ¹H NMR spectra.     

Cobalt Chalcogenide Clusters. Synthesis,Characterization and DFT Calculations of [Co4Se2(CO)10] and [Co4Te2(CO)11]. Crystal Structure of [Co8Se4(CO)16(μ‐dppa)2]

The reactions of [Co₂(CO)₈] with E(SiMe₃)₂ (E = Se, Te) in CH₂Cl₂ result in the formation of the compounds [Co₄Se₂(CO)₁₀]> ( 1 ) and [Co₄Te₂(CO)₁₁] ( 2 ), respectively. Both cluster complexes have similar molecular structures in which the cobalt atoms form four‐membered rings with μ₄‐bridging chalcogen atoms (Se and Te) above and below the plane of the metal atoms and the carbonyl ligands as either terminal or μ₂‐bridging ligands. DFT‐calculations for both compounds have been carried out in order to obtain some more information about their electronic distribution. In the presence of the phosphine Ph₂PC≡CPPh₂ (dppa), the reaction of [Co₂(CO)₈] with Se(SiMe₃)₂ leads to the formation of [Co₈Se₄(CO)₁₆(μ‐dppa)₂] ( 3 ). During the reaction two molecules of [Co₂(CO)₈] have been added to the acetylene groups of the dppa ligands, whilst the remaining cobalt atoms coordinate to the phosphorus atoms of the phosphine. In this compounds the selenium atoms act as μ₃‐ligands, bridging the metal atoms bonded to the phosphorus with those bonded to the acetylene groups.