萘氧乙酸及咪唑构筑的锌(Ⅱ)和铜(Ⅱ)配合物的水热合成、晶体结构及荧光性质

通过水热的方法合成得到2个由萘氧乙酸及咪唑配体构筑的配合物Zn(2-naph)₂(imi)₂ (1)和2Cu(2-naph)₂(imi)₂(H₂O)·Cu(2-naph)₂(imi)₂(H₂O) (2)(2-naph=2-naphthoxyacetate,imi=imidazole),它们的结构通过X射线晶体衍射、红外光谱和元素分析得到确定。在配合物1中,锌原子与来自不同2-萘氧乙酸配体中的2个羧酸氧原子和不同的咪唑分子中的2个氮原子形成了变形的四面体的几何构型。单个分子通过N-H…O氢键连接形成了一维链,然后在C-H…π弱作用下形成了三维结构。配合物2有2个独立的铜中心,它们有几乎相同的配位环境。每个铜中心都是变形的四方锥的配位构型。来自不同的2-萘氧乙酸配体中的2个羧酸氧原子和不同的咪唑分子中的2个氮原子形成了一个相对规则的四方锥赤道平面,配位水分子位于平面上方。配合物2的分子通过N-H…O和O-H…O氢键连接形成了二维结构。2个配合物的热稳定和固体荧光性质在本文中也得到了研究和讨论。     

Synthesis and Crystal Structure of a Novel 2-Fold Interpenetrating Three-dimensional Coordination Polymer,{[Co_3（byip）_2（bix）_3（H_2O）_2]·H_2O}_n

The title coordination polymer including two crystallographically independent Co2+ ions is hydrothermally synthesized, in which the Co(1) 2+ ion is four-coordinated by two carboxylate oxygen atoms from two different 5-(benzoic acid-4-yldiazenyl)isophthalate (byip3-) anions and two nitrogen atoms from two distinct 1,4-bis(imidazol-1-ylmethyl) benzene (bix) ligands displaying a tetrahedral geometry. The Co(2) 2+ ion is six-coordinated by two water molecules at the apical positions, and two carboxylate oxygen atoms and two nitrogen atoms at the equatorial positions, affording a slightly distorted octahedron. Two Co(1)2+ and two Co(2)2+ ions are linked together by four byip3- anions forming a 44-membered motif and these motifs are further arranged into a three-dimensional framework through bix ligands along the a axis with a larger channel (ca. 22.70×11.01). Each individual network interpenetrates with the other identical network in a parallel fashion to generate a 2-fold interpenetrating array with the {62.84}{63}2{64.82}2 topology.     

2，2-联吡啶-3，3-二羧酸桥联的具有2D网格结构的Mn配位聚合物的合成、晶体结构

A Manganese(Ⅱ) polymer {[Mn(bpdc)(bipy)(H₂O)]·4.5H₂O}_n has been synthesized (bpdc=2,2-bipyridine-3,3-dicarboxylate,bipy=4,4-bipyridine) and characterized by IR, UV, elemental analysis and X-ray crystal structure determination . It crystallizes in Monoclinic system, space group P2/n with a=1.010 13(8) nm, b=1.164 66(9) nm, c=2.147 40(16) nm, β=98.22 20(10)°, V=2.500 4(3) nm³, Z=4, D_c=1.467 g·cm^-3, F(000)=1 144, R₁=0.049 0, wR₂=0.141 2. The crystal structure shows that the Mn²⁺ ions have octahedral coordination geometry with two coordination situations. The Mn²⁺ (1) ion is coordinated with two N atoms of two bipy, and chelated by four O atoms from four carboxylate groups of two bpdc ligands. The neighbor Mn²⁺ (2) ion is coordinated with two oxygen atoms from two water, two N atoms of two 4,4-bipy and two O atoms from two carboxylate groups of two bpdc ligands. Mn(1) and Mn(2) ions are bridged by bpdc and bipy ligands, forming a novel 2D network. CCDC: 651043.     

一维链状配位聚合物{[Cd2(1，8-nap)2(H2O)2](bpp)2}n的水热合成、晶体结构及荧光性质

The title complex, {[Cd₂(1,8-nap)₂(H₂O)₂](bpp)₂}_n(1), a cadmium complex based on mixed naphthalene-1,8-dicarboxylate (1,8-nap) and flexible 1,3-bi(4-pyridyl)propane (bpp) ligands, has been hydrothermally synthes-ized. It consists of a one-dimensional chain along c axis, which is derived from dimeric unit [Cd₂(1,8-nap)₂(H₂O)₂] linked by a pair of bpp ligands. In every [Cd₂(1,8-nap)₂(H₂O)₂] dimeric unit, two 1,8-nap act as bridging ligands to connect two Cd(Ⅱ) atoms, forming a sixteen-membered ring. Each Cd(Ⅱ) atom is in a distorted octahedral environment, coordinated by one aqua, two 1,8-nap and two bridging bpp ligands. In addition, two bridging bpp ligands connected two neighboring Cd(Ⅱ) atoms form a twenty-four-membered ring. The TGA and Luminescence property in solid state of complex 1 have been further studied and discussed in this paper. CCDC: 669293.     

Synthesis and Crystal Structure of a Novel 2-Fold Interpenetrating Three-dimensional Coordination Polymer, {[Co3(byip)2(bix)3(H20)2]·H2O}n

T The title coordination polymer including two crystallographically independent Co<'2+> ions is hydrothermally synthesized, in which the Co(1)<'2+> ion is four-coordinated by two carboxylate oxygen atoms from two different 5-(benzoic acid-4-yldiazenyl)isophthalate(byip<'3->)anions and two nitrogen atoms from two distinct 1,4-bis(imidazol-1-ylmethyl)benzene(bix)ligands displaying a tetrahedral geometry. The Co(2)<'2+> ion is six-coordinated by two water molecules at the apical positions, and two carboxylate oxygen atoms and two nitrogen atoms at the equatorial positions, affording a slightly distorted octahedron. Two Co(1)<'2+> and two Co(2)<'2+> ions are linked together by four byip<'3-> anions forming a 44-membered motif and these motifs are further arranged into a three-dimensional framework through bix ligands along the a axis with a larger channel(ca.22.70(A)×11.01(A)). Each individual network interpenetrates with the other identical network in a parallel fashion to generate a 2-fold interpenetrating array with the {6<'2>.8<'4>} {6<'3>}<,2> {6<'4>.8<'2>}<,2> topology.     

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.     

具有梯形结构钴(Ⅱ)配位聚合物的合成及晶体结构

Co(NO₃)₂, N-carbazolyacetic acid and 4,4′-bipyridyl can give rise to a novel coordination polymer [CO₂(Cabo)₂(NO₃)₂(4,4′-bipy)₂]_n using a fritted U-tube. Single crystal X-ray diffraction displays in the complex, each Co(Ⅱ) is six-coordinated by two N atoms from different 4,4′-bipyridyl ligands, two O atoms of the bridge from two N-carbazolyacetic acid and two O atoms of one nitrate anion to form a distorted octahedral. Two O atoms of the carboxyl group act as bridge to link two Co(Ⅱ) atoms. The resulting structure is a ladder polymer. CCDC: 211713.     

Formation of dinuclear,macrocyclic, and chain structures from HgI(2) and a semirigid benzimidazole-based bridging ligand: an example of ring-opening supramolecular isomerism

The reactions of HgI(2) with the semirigid ditopic ligand 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene (bbimms) afforded three new complexes, [Hg(2)(mu-I)(2)I(2)(bbimms)] (1), [Hg(2)I(4)(bbimms)(2)] (2), and catena-poly[HgI(2)(bbimms)] (3). The ligand and all complexes have been structurally characterized by single-crystal X-ray diffraction. 1 is a triply bridged dinuclear complex comprised of two Hg(II) ions, one bridging ligand, two bridging I(-) anions, and two terminal I(-) anions. 2 is a dinuclear metallamacrocycle comprised of two Hg(II) ions, two bridging ligands, and four terminal I(-) anions, while 3 is a helical chain with the repeating unit of HgI(2)(bbimms). 2 and 3 can be classified as supramolecular isomers, and both are related to the triply bridged precursor 1 via the addition of one more ligand in a ring-opening process.     

Synthesis, Crystal Structure and Electrochemical Properties of a One-dimensional Chain Coordination Polymer [Mn(NAA)_2(4,4’-bipy)(H_2O)_4]_n

A novel one-dimensional chain coordination polymer [Mn(NAA)2(4,4’-bipy)(H2O)4]n has been synthesized with α-naphthaleneacetic acid, 4,4’-bipy and manganese(II) sulfate as raw ma-terials. Crystal data for this complex: monoclinic, space group P21/c, a = 1.1421(2), b = 1.6337(3), c = 0.94177(19) nm, β = 112.15(3)o, V = 1.6275(6) nm3, Dc = 1.407 g/cm3, Z = 2, μ(MoKα) = 0.467 mm-1, F(000) = 722, S = 1.007, R = 0.0412 and wR = 0.1022. The crystal structure shows that two neighboring manganese(II) ions are linked together by one 4,4?-bipy molecule, and the whole complex molecule forms a one-dimensional chain structure. Each manganese(II) ion is coordinated with two oxygen atoms of two α-naphthaleneacetic acid molecules, two nitrogen atoms of two 4,4?-bipy molecules and two oxygen atoms from two water molecules, giving a distorted octahedral coordination geometry. The electrochemical properties were also analyzed.     

Synthesis,Crystal Structure and Electrochemical Properties of a One-dimensional Chain Coordination Polymer [Mn （NAA ）2（ 4,4′-bipy ） （H2O）4]n

A novel one-dimensional chain coordination polymer [Mn（NAAh（4,4′-bipy）（H2O）4], has been synthesized with a-naphthaleneacetic acid, 4,4′-bipy and manganese（Ⅱ） sulfate as raw materials. Crystal data for this complex： monoclinic, space group P21/c, a = 1.1421（2）, b = 1.6337（3）, c = 0.94177（19） nm, β = 112.15（3）°, V = 1.6275（6） nm^3, De = 1.407 g/cm^3, Z = 2, μ（MoKa） = 0.467 mm^-1, F（000） = 722, S = 1.007, R= 0.0412 and wR = 0.1022. The crystal structure shows that two neighboring manganese（Ⅱ） ions are linked together by one 4,4′-bipy molecule, and the whole complex molecule forms a one-dimensional chain structure. Each manganese（Ⅱ） ion is coordinated with two oxygen atoms of two a-naphthaleneacetic acid molecules, two nitrogen atoms of two 4,4′-bipy molecules and two oxygen atoms from two water molecules, giving a distorted octahedral coordination geometry. The electrochemical properties were also analyzed.     

Multicomponent self-assembly of a nested co(24) @co(48) metal-organic polyhedral framework

A tale of two polyhedra: Two nested Archimedean metal-organic polyhedra, a rhombicuboctahedron (Co(48) cage) and a cuboctahedron (Co(24) cage), have been assembled from two types of cobalt dimers and two complementary ligands. Within the 3D covalent cubic array of outer Co(48) cages and framework lie encapsulated inner Co(24) cages that are linked into a separate "hidden" 3D framework.     

Crystal structure of [Pt2I4(TEPOP)2] (TEPOP = tetraethyldiphosphite).

The structure of the dinuclear complex [Pt2I4(TEPOP)2] (TEPOP = tetraethyldiphosphite) was determined by X-ray diffraction. The two platinum atoms are doubly bridged by two (EtO)2POP(OEt)2 ligands and constitute an eight-membered ring. The platinum atoms have a square-planar geometry, which are completed by two phosphorous and two iodine atoms in a mutually cis arrangement.     

Synthesis,characterization, and crystal structures of two new divalent metal complexes of N,N'-bis(phosphonomethyl)-1,10-diaza-18-crown-6: a hydrogen-bonded 1D array and a 3D network with a large channel

Reaction of N,N'-bis(phosphonomethyl)-1,10-diaza-18-crown-6 (H(4)L) with copper(II) acetate in 1:1 ethanol/water mixed solvents afforded a new crystal-engineered supramolecular metal phosphonate, Cu(H(2)L) (complex 1). By reaction of the same ligand with cadmium(II) nitrate in a 2:1 (M/L) ratio in methanol, a cadmium(II) complex with a 3D network structure was isolated, Cd(2.75)(L)(H(2)O)(7) x 1.5NO(3) x 7H(2)O x MeOH (complex 2). The copper(II) complex crystallized in the monoclinic space group P2(1)/c, with a =10.125(4), b = 14.103(6), and c = 14.537(6) A, beta = 91.049(8) degrees, V = 2075.4(16) A(3), and Z = 2. The Cu(II) ions in complex 1 are 6-coordinated by two phosphonate oxygen atoms, two nitrogen, and two oxygen atoms from the crown ether ring. Their coordination geometry can be described as Jahn-Teller-distorted octahedral, with elongated Cu-O(crown) distances (2.634(4) and 2.671(4) A for Cu(1) and Cu(2), respectively). The other two crown oxygen atoms remain uncoordinated. Neighboring two Cu(H(2)L) units are further interlinked via a pair of strong hydrogen bonds between uncoordinated phosphonate oxygen atoms, resulting in a one-dimensional supramolecular array along the a axis. The cadmium(II) complex is tetragonal, P4(2)/n (No. 86) with a = 20.8150(9) and c = 18.5846(12) A, V = 8052.0(7) A(3), and Z = 8. Among four cadmium(II) atoms in an asymmetric unit, one is 8-coordinated by four chelating phosphonate groups, the second one is 8-coordinated by 6 coordination atoms from a crown ring and two oxygen atoms from two phosphonate groups, the third Cd(II) atom is octahedrally coordinated by three aqua ligands and three phosphonate oxygen atoms from three phosphonate groups, and the fourth one is 6-coordinated by four aqua ligands and two oxygen atoms from two phosphonate groups in a distorted octahedral geometry. These cadmium atoms are interconnected by bridging phosphonate tetrahedra in such a way as to form large channels along the c direction, in which the lattice water molecules, methanol solvent, and nitrate anions reside. The effect of extent of deprotonation of phosphonic acids on the type of complex formed is also discussed.     

Bonding mode of a bifunctional P approximately Si-H ligand in the ruthenium complex "Ru(PPh2CH2OSiMe2H)3"

The phosphinosilane compound PPh 2CH 2OSiMe 2H is potentially a bifunctional P approximately Si-H ligand. By treatment with the Ru (II) precursor RuH 2(H 2) 2(PCy 3) 2, the complex Ru(PPh 2CH 2OSiMe 2H) 3 ( 2), resulting from the coordination of three ligands and the displacement of two PCy 3 and two dihydrogen ligands, was formed. The different bonding modes for each of the three bifunctional P approximately Si-H ligands are discussed on the basis of multinuclear NMR, X-ray diffraction, and density functional theory studies. One ligand acts as a monodentate phosphine ligand with a pendant Si-H group, whereas the two others act as bidentate ligands with different Si-H bond activations. Indeed, an intermediate structure between two arrested forms 2a and 2b can be proposed: a dihydrido(disilyl)ruthenium(IV) species (form 2a) resulting from two Si-H oxidative additions or a hydrido(silyl)ruthenium(II) species (form 2b) presenting an agostic Si-H bond and only one oxidative addition.     

茂铁基稀土铈配合物的合成与结构

本文利用单羧基二茂铁Fc-COOH和1，1′-二羧基二茂铁HOOC-Fc-COOH作为配体分别合成了双核铈配合物Ce₂(FcCOO)₆ (1)和二维层状配位聚合物Ce₂(OOC-Fc-COO)₃(2)，测定了两种配合物的晶体结构。配合物1中的金属铈离子为九配位结构，分别与周围的羧基二茂铁上的氧原子和作为辅助配体的水分子配位，茂铁间的π-π相互作用将配合物1的二聚体单元连结在一起形成二维的网状结构。配合物2中的金属铈离子亦为九配位结构，分别与周围的羧基二茂铁上的氧原子，作为辅助配体的水分子和甲醇配位形成类似于配合物1的二聚体单元，1，1′-二羧基二茂铁HOOC-Fc-COOH作为桥基配体将二聚体单元连结在一起，形成二维网状的配位聚合物。     

MOLECULAR RIBBONS COMPOSED OF CALCIUM(II) IONS BRIDGED BY CARBOXYLATE AND WATER OXYGEN ATOMS IN THE CRYSTALS OF Ca(II) COMPLEX WITH 5-METHYLPYRAZINE-2-CARBOXYLATE LIGANDS

Abstract

Crystals of monoaquo(μ-5-methylpyrazine-2-carboxylato-N,O,O′), (5-methylpyrazine-2-carboxyato-N,O)di(μ-aquo-O,O)calcium(II) contain molecular ribbons in which two adjacent calcium(II) ions are bridged by two bidentate oxygen atoms donated by two ligand molecules on one side and bidentate oxygen atoms of two water molecules on the other. The coordination polyhedron around the Ca(II) ion is a pentagonal bipyramid. The vertices of its pentagonal base are composed of two bridging water oxygen atoms, two carboxylate oxygen atoms of two ligand molecules and a nitrogen atom belonging to one of the bridging ligands. A coordinated water molecule constitutes the apex of the pyramid on one side of the base, while the N, O bonding moiety of a second ligand molecule makes two apices on the other side of the base. The ribbons are held together by a system of hydrogen bonds.     

Valence Tautomerism in Octahedral and Square‐Planar Phenoxyl–Nickel(II) Complexes: Are Imino Nitrogen Atoms Good Friends?

The two tetradentate ligands H(2)L and H(2)L(Me) afford the slightly distorted square-planar low-spin Ni(II) complexes 1 and 2, which comprise two coordinated phenolate groups. Complex 1 has been electrochemically oxidized into 1(+), which contains a coordinated phenoxyl radical, with a contribution from the nickel orbital. In the presence of pyridine, 1(+) is converted into 1(Py) (+), an octahedral phenolate nickel(III) complex with two pyridines axially coordinated: An intramolecular electron transfer (valence tautomerism) is promoted by the geometrical changes, from square planar to octahedral, around the metal center. The tetradentate ligand H(2)L(Me), in the presence of pyridine, and the hexadentate ligand H(2)L(Py) in CH(2)Cl(2) afford, respectively, the octahedral high-spin Ni(II) complexes 2(Py) and 3, which involve two equatorial phenolates and two axially coordinated pyridines. At 100 K, the one-electron-oxidized product 2(Py) (+) comprises a phenoxyl radical ferromagnetically coupled to the high-spin Ni(II) ion, with large zero-field splitting parameters, while 3(+) involves a phenoxyl radical antiferromagnetically coupled to the high-spin Ni(II) ion.     

Spectroscopic studies of bimetallic complexes derived from tridentate or tetradentate Schiff bases of some di- and tri-valent transition metals

Two series of new binuclear complexes with Schiff base ligands, H(4)L(a) or H(2)L(b), derived from the reaction of 4,6-diacetylresorcinol and ethylenediamine, in the molar ratio 1:1 and 1:2 have been prepared, respectively. The two ligands react with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Cr(III) and Fe(III)-nitrates to get binuclear complexes. The ligands were characterized by elemental analysis, IR, UV-vis, (1)H NMR and mass spectra. The complexes were synthesized by direct and template methods. Different types of products were obtained for the same ligand and metal salts according to the method of preparation. The H(4)L(a) ligand behaves as a macrocyclic tetrabasic with two N(2)O(2) sits, while the H(2)L(b) ligand behaves as a dibasic with two N(2)O sites. The H(4)L(a) ligand is a compartmental ligand which hosts the two metal ions at the centers of two cis-N(2)O(2) sites, while the metal complexes of H(2)L(b) ligand are binuclear, where the ligand hosts two metal ions at the centers of two N(2)O sites. In both cases, deprotonation of the hydrogen atoms of the phenolic OH groups occur except in the case of the Ni(II), Fe(III) and Cr(III) complexes. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either octahedral or tetrahedral. The structures are consistent with the IR, UV-vis, ESR, (1)H NMR, mass spectra, and thermal gravimetric analysis (TGA/DTA) as well as conductivity and magnetic moment measurements.     

New cobalt(II) and zinc(II) coordination frameworks incorporating a pyridyl-pyrazole ditopic ligand

The metal-directed assembly of new molecular frameworks incorporating 4-(4-pyridyl)pyrazole (L), containing non-linear coordination vectors, is presented. Three metallo-arrays of types [Co(LH)2(NO3)4], [Co(LH)2(H2O)4][NO3]4.H2O and [Zn2(L-H)2Cl2].2EtOH are reported. The cobalt(II) in [Co(LH)2(NO3)4] displays distorted octahedral geometry, with the two protonated pyridyl-pyrazole ligands coordinated through their pyrazole nitrogen atoms in a trans-orientation; the remaining four coordination sites are occupied by nitrate anions. Two internal hydrogen bonds occur between each pyrazole NH and the oxygens of adjacent coordinated nitrato ligands. Short intermolecular hydrogen bonds also occur between the two pyridinium hydrogens and bound nitrate ligands on different molecules to yield a two-dimensional hydrogen-bonded array. Two of these arrays interpenetrate to form an extended two dimensional layer; such layers stack throughout the crystal structure. A second product of type [Co(LH)2(H2O)4][NO3]4.H2O exists as two crystallographically independent, but chemically similar, forms. In each form, the two protonated pyridyl-pyrazole ligands occupy trans positions about the cobalt, with the remaining four coordination sites being filled by water molecules to yield a distorted octahedral coordination geometry. Intramolecular hydrogen-bonding is observed between the two non-coordinated pyrazoyl nitrogen atoms and bound water oxygen atoms. The third complex, [Zn2(L-H)2Cl2].2EtOH, contains dimer units consisting of two zinc(II) ions bridged by two pyrazoylate groups in which the coordination geometry of each zinc approximates a tetrahedron. Each zinc is bound to two deprotonated pyridine-pyrazole ligands (L-H), one pyridyl group (from a different dimeric unit) and one chloro ligand. Each pyridyl nitrogen thus connects each of these zinc dimers to an adjacent dimer unit, forming a three-dimensional network containing small voids. The latter are occupied by ethanol molecules which form hydrogen bonds to the chloro ligands.     

Syntheses,structures, and properties of imidazolate-bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) dinuclear complexes of a single macrocyclic ligand with two hydroxyethyl pendants

The imidazolate-bridged homodinuclear Cu(II)-Cu(II) complex, [(CuimCu)L]ClO(4).0.5H(2)O (1), and heterodinuclear Cu(II)-Zn(II) complex, [(CuimZnL(-)(2H))(CuimZnL(-)(H))](ClO(4))(3) (2), of a single macrocyclic ligand with two hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,2(11,14)]triaconta-1,11,13,24,27,29-hexaene), have been synthesized as possible models for copper-zinc superoxide dismutase (Cu(2),Zn(2)-SOD). Their crystal structures analyzed by X-ray diffraction methods have shown that the structures of the two complexes are markedly different. Complex 1 crystallizes in the orthorhombic system, containing an imidazolate-bridged dicopper(II) [Cu-im-Cu](3+) core, in which the two copper(II) ions are pentacoordinated by virtue of an N4O environment with a Cu.Cu distance of 5.999(2) A, adopting the geometry of distorted trigonal bipyramid and tetragonal pyramid, respectively. Complex 2 crystallizes in the triclinic system, containing two similar Cu-im-Zn cores in the asymmetric unit, in which both the Cu(II) and Zn(II) ions are pentacoordinated in a distorted trigonal bipyramid geometry, with the Cu.Zn distance of 5.950(1)/5.939(1) A, respectively. Interestingly, the macrocyclic ligand with two arms possesses a chairlike (anti) conformation in complex 1, but a boatlike (syn) conformation in complex 2. Magnetic measurements and ESR spectroscopy of complex 1 have revealed the presence of an antiferromagnetic exchange interaction between the two Cu(II) ions. The ESR spectrum of the Cu(II)-Zn(II) heterodinuclear complex 2 displayed a typical signal for mononuclear trigonal bipyramidal Cu(II) complexes. From pH-dependent ESR and electronic spectroscopic studies, the imidazolate bridges in the two complexes have been found to be stable over broad pH ranges. The cyclic voltammograms of the two complexes have been investigated. Both of the two complexes can catalyze the dismutation of superoxide and show rather high activity.