Synthesis, characterization, and bromine substitution by 4,4'-di(5-nonyl)-2,2'-bipyridine in Cu(II)(4,4'-di(5-nonyl)-2,2'-bipyridine)Br(2)

The crystal structure of a novel compound Cu(II)(dNbpy)Br(2) (dNbpy = 4,4'-di(5-nonyl)-2,2'-bipyridine), which is used in the reverse atom transfer radical polymerization, is reported. Cu(II)(dNbpy)Br(2) crystallizes in the triclinic P1 space group with a = 12.5283(11) A, b = 15.0256(14) A, c = 17.7900(16) A, alpha = 90.350(2) degrees, beta = 99.360(2) degrees, gamma = 107.937(2) degrees, and Z = 2. The Cu(II) center in the complex has a distorted square planar geometry and is coordinated by two nitrogen atoms of a single dNbpy ligand (Cu-N = 2.011(7) and 2.022(7) A) and two bromine atoms (Cu-Br = 2.3621(14) and 2.3567(13) A). The similarity of the absorption spectra in the solid state and in solution suggested that the geometry of the complex remained unchanged upon dissolution. In the presence of dNbpy, Cu(II)(dNbpy)Br(2) undergoes Br substitution to form ionic [Cu(II)(dNbpy)(2)Br](+)[Br](-). DeltaH degrees and DeltaS degrees values for this equilibrium were negative and dependent on the polarity of the medium. It was found that, under the typical polymerization conditions (T > or =90 degrees C and the total copper concentration in the range 1.0 x 10(-2)-1.0 x 10(-1) M), Cu(II)Br(2) and 2 equiv of dNbpy will predominantly form the neutral Cu(II)(dNbpy)Br(2) complex. In a polar medium under the same conditions, [Cu(II)(dNbpy)(2)Br](+)[Br](-) is preferred.     

Self-assembly of D-penicillaminato M6M'8 (M = Ni(II), Pd(II), Pt(II); M' = Cu(I), Ag(I)) clusters and their organization into extended La(III)M6M'8 supramolecular structures

A series of chiral M(6)M'(8) cluster compounds having twelve free carboxylate groups, [M(6)M'(8)(D-pen-N,S)(12)X](5-) (M/M'/X = Pd(II)/Ag(I)/Cl(-) ([1](5-)), Pd(II)/Ag(I)/Br(-) ([2](5-)), Pd(II)/Ag(I)/I(-) ([3](5-)), Ni(II)/Ag(I)/Cl(-) ([4](5-)), Pt(II)/Ag(I)/Cl(-) ([5](5-)), Pd(II)/Cu(I)/Cl(-) ([6](5-)); D-H(2)pen = D-penicillamine), in which six cis-[M(D-pen-N,S)(2)](2-) square-planar units are bound to a [M'(8)X](7+) cubic core through sulfur-bridges, was synthesized by the reactions of cis-[M(D-pen-N,S)(2)](2-) with M' in water in the presence of halide ions. These M(6)M'(8) clusters readily reacted with La(3+) in aqueous buffer to form La(III)(2)M(6)M'(8) heterotrimetallic compounds, La(2)[1](CH(3)COO), La(2)[2](CH(3)COO), La(2)[3](CH(3)COO), La(2)[4](CH(3)COO), La(2)[5](CH(3)COO) and La(2)[6]Cl, in which the M(6)M'(8) cluster units are linked by La(3+) ions through carboxylate groups in a 1?:?2 ratio. While the La(III)(2)M(6)Ag(I)(8) compounds derived from [1](5-), [2](5-), [3](5-), [4](5-) and [5](5-) have a 1D helix supramolecular structure with a right-handedness, the La(III)(2)Pd(II)(6)Cu(I)(8) compound derived from [6](5-) has a 2D sheet-like structure with a triangular grid of the Pd(II)(6)Cu(I)(8) cluster units. When aqueous HCl was added to the reaction solution of [6](5-) and La(3+), another La(III)(2)Pd(II)(6)Cu(I)(8) heterotrimetallic compound, La(2)[6]Cl·HCl, in which the Pd(II)(6)Cu(I)(8) cluster units are linked by La(3+) ions to form a 2D structure with a rectangular grid, was produced. The solid-state structures of these La(III)(2)M(6)M'(8) compounds, determined by single-crystal X-ray crystallography, along with the spectroscopic properties of the M(6)M'(8) cluster compounds in solution, are described.     

A complete series of copper(II) halide complexes (X = F, Cl, Br, I) with a novel Cu(II)-C(sp3) bond

A complete series of copper(ii) halide complexes [CuX(tptm)](X = F (), Cl (), Br (), I (); tptm = tris(2-pyridylthio)methyl) with a novel Cu(II)-C(sp(3)) bond has been prepared by the reactions of [Cu(tptm)(CH(3)CN)]PF(6)(.PF(6)) with corresponding halide sources of KF or n-Bu(4)NX (X = Cl, Br, I), and the trigonal bipyramidal structures have been confirmed by X-ray crystallography and/or EPR spectroscopy. The iodide complex easily liberates the iodide anion in acetonitrile forming the acetonitrile complex as a result. The EPR spectra of the complexes showed several superhyperfine structures that strongly indicated the presence of spin density on the halide ligands through the Cu-X bond. The results of DFT calculations essentially matched with the X-ray crystallographic and the EPR spectroscopic results. Cyclic voltammetry revealed a quasi-reversible reduction wave for Cu(II)/Cu(I) indicating a trigonal pyramidal coordination for Cu(I) states. A coincidence of the redox potential for all [CuX(tptm)](0/+) processes indicates that the main oxidation site in each complex is the tptm ligand.     

First example of a 2:1 cocrystal of mixed Cu(I)/Cu(II) complexes and a novel ferromagnetic bis(mu-hydroxo)dicopper(II) complex with a bis(pyrazol-1-yl)methane bidentate ligand

A unique 2:1 cocrystal of mixed Cu(I)/Cu(II) complexes [Cu(I)(H2CPz2)(MeCN)2](ClO4) (1) and [Cu(II)(H2CPz2)2(ClO4)2] (4), a novel ferromagnetic ClO(4-)-bridged bis(mu-hydroxo)dicopper(II) complex, [Cu2(H2CPz2)2(OH)2(ClO4)](ClO4)(CH3CN)(0.5) (5), and a bischelated copper(I) complex, [Cu(H2CPz2)2](ClO4) (2), prepared from a one-pot reaction of [Cu(MeCN)4](ClO4) and H2CPz2, are described. The structures of these complexes have been determined by X-ray crystallographic methods. The Cu(I)-N(acetonitrile) bond distances in complex 1 are nonequivalent (1.907(8) and 2.034(9) A), leading to the dissociation of one MeCN to form a Y-shaped complex, [Cu(I)(H2CPz2)(MeCN)](ClO4) (3), which is oxidized readily in air to form complex 5 with a butterfly Cu2O2 core.     

Dioxygen activation of a trinuclear Cu(I)Cu(I)Cu(I) cluster capable of mediating facile oxidation of organic substrates: competition between O-atom transfer and abortive intercomplex reduction

The dioxygen activation of a series of Cu(I)Cu(I)Cu(I) complexes based on the ligands (L) 3,3'-(1,4-diazepane- 1,4-diyl)bis(1-{[2-(dimethylamino)ethyl](methyl)amino}propan-2-ol)(7-Me) or 3,3'-(1,4-diazepane-1,4-diyl)bis(1-{[2-(diethylamino)ethyl](ethyl)amino}propan-2-ol)(7-Et) forms an intermediate capable of mediating facile O-atom transfer to simple organic substrates at room temperature. To elucidate the dioxygen chemistry, we have examined the reactions of 7-Me, 7-Et, and 3,3'-(1,4-diazepane-1,4-diyl)bis[1-(4-methylpiperazin-1-yl)propan-2-ol] (7-N-Meppz) with dioxygen at -80, -55, and -35?°C in propionitrile (EtCN) by UV-visible, 77?K EPR, and X-ray absorption spectroscopy, and 7-N-Meppz and 7-Me with dioxygen at room temperature in acetonitrile (MeCN) by diode array spectrophotometry. At both -80 and -55?°C, the mixing of the starting [Cu(I)Cu(I)Cu(I)(L)](1+) complex (1) with O(2)-saturated propionitrile (EtCN) led to a bright green solution consisting of two paramagnetic species: the green dioxygen adduct [Cu(II)Cu(II)(μ-η(2):η(2)-peroxo)Cu(II)(L)](2+) (2) and the blue [Cu(II)Cu(II)(μ-O)Cu(II)(L)](2+) species (3). These observations are consistent with the initial formation of [Cu(II)Cu(II)(μ-O)(2)Cu(III)(L)](1+)(4), followed by rapid abortion of this highly reactive species by intercluster electron transfer from a second molecule of complex 1 to give the blue species 3 and subsequent oxygenation of the partially oxidized [Cu(II)Cu(I)Cu(I)(L)](2+)(5) to form the green dioxygen adduct 2. Assignment of 2 to [Cu(II)Cu(II)(μ-η(2):η(2)-peroxo)Cu(II)(L)](2+) is consistent with its reactivity with water to give H(2)O(2) and the blue species 3, as well as its propensity to be photoreduced in the X-ray beam during X-ray absorption experiments at room temperature. In light of these observations, the development of an oxidation catalyst based on the tricopper system requires consideration of the following design criteria: 1)?rapid dioxygen chemistry; 2)?facile O-atom transfer from the activated cluster to substrate; and 3)?a suitable reductant to rapidly regenerate complex 1 to accomplish efficient catalytic turnover.     

Three-coordinate [Cu(II)X(3)](-) (X=Cl, Br), trapped in a molecular crystal

Mixtures of [Ph(3)PNPPh(3)](+)Cl(-) with CuBr(2) (or CuBr(2)+CuCl(2)) in ethanol/dichloromethane yield crystals containing three-coordinate copper(II) with mixed chloride and bromide ligands, namely [Ph(3)PNPPh(3)](+)[CuCl(0.9)Br(2.1)](-) (1) and [Ph(3)PNPPh(3)](+)[CuCl(2.4)Br(0.6)](-) (2). The trigonal-planar coordination of copper(II) is angularly distorted but unambiguous, as there is no other halide ligand within 6.7 A of the copper atom. Density functional theory (DFT) calculations on planar [CuClBr(2)](-) show that the energy surface for angle bending is very soft. Crystallisation in the presence of CH(3)CN yields [Ph(3)PNPPh(3)](+)[CuCl(0.7)Br(2.3)(NCCH(3))](-) (3), in which there is additional secondary coordination by NCCH(3) (Cu-N 2.44 A). DFT calculations of the potential energy surface for this secondary coordination show that it is remarkably flat (<3 kcal mol(-1) for a variation of Cu-N by 0.8 A). The crystal packing in 1, 2 and 3, which involves multiple phenyl embraces between [Ph(3)PNPPh(3)](+) ions and numerous C-H...Cl and C-H...Br motifs, is associated with intermolecular energies that are larger than the variations in intramolecular energies. For reference, the crystal structures of [Ph(3)PNPPh(3)(+)](2)[Cu(2)Cl(6)](2-) (4) and [Ph(3)PNPPh(3)(+)](2)[Cu(2)Br(6)](2-) (5) are described. We conclude 1) that three-coordinate copper(II) with monatomic halide ligands, although uncommon, can be regarded as normal, 2) that steric control by ligands is not necessary to enforce three-coordination, 3) that a hydrophobic aryl environment stabilises [Cu(Cl/Br)(3)](-), and 4) that the energy change in the transition from three- to four-coordinate copper(II) is very small (ca 5 kcal mol(-1)).     

Phenolate and phenoxyl radical complexes of Co(II) and Co(III)

The new phenol-imidazole pro-ligands (R)LH react with Co(BF(4))(2).6H(2)O in the presence of Et(3)N to form the corresponding [Co(II)((R)L)(2)] compound (R = Ph (1), PhOMe (2), or Bz (3)). Also, (Bz)LH, reacts with Co(ii) in the presence of Et(3)N and H(2)O(2) to form [Co(III)((Bz)L)(3)](4). The structures of 1.2.5MeCN, 2.2DMF, 3.4MeOH, and 4.4DMF have been determined by X-ray crystallography. 1, 2, and 3 each involve Co(II) bound to two N,O-bidentate ligands with a distorted tetrahedral coordination sphere; 4 involves Co(III) bound to three N,O-bidentate ligands in a mer-N(3)O(3) distorted octahedral geometry. [Co(II)((R)L)(2)](R = Ph or PhOMe) undergo two, one-electron, oxidations. The products of the first oxidation, [1](+) and [2](+), have been synthesised by the chemical oxidation of 1 and 2, respectively; these cations, formulated as [Co(II)((R)L*)((R)L)(2)](+), comprise one phenoxyl radical and one phenolate ligand bound to Co(II) and are the first phenoxyl radical ligand complexes of tetra-coordinated Co(II). 4 undergoes two, one-electron, ligand-based oxidations, the first of which produces [4](+), [Co(III)((Bz)L*)((Bz)L)(2)](+). Unlike [1](+) and [2](+), product of the one-electron oxidation of [Co(II)((Bz)L)(2)], [3](+), is unstable and decomposes to produce [4](+). These studies have demonstrated that the chemical properties of [M(II)((R)L*)((R)L)(2)](+)(M = Co, Cu, Zn) are highly dependent on the nature of both the ligand and the metal centre.     

Microwave-assisted construction of ferromagnetic coordination polymers of [W(V)(CN)8]3- with Cu(II)-pyrazole synthons

The microwave-mediated self-assembly of [W(V)(CN)(8)](3-) with Cu(II) in the presence of pyrazole ligand resulted in the formation of three novel assemblies: Cu(II)(2)(Hpyr)(5)(H(2)O)[W(V)(CN)(8)](NO(3))·H(2)O (1), {Cu(II)(5)(Hpyr)(18)[W(V)(CN)(8)](4)}·[Cu(II)(Hpyr)(4)(H(2)O)(2)]·9H(2)O (2), and Cu(II)(4)(Hpyr)(10)(H(2)O)[W(V)(CN)(8)](2)(HCOO)(2)·4.5H(2)O (3) (Hpyr =1H-pyrazole). Single-crystal X-ray structure of 1 consists of cyanido-bridged 1-D chains of vertex-sharing squares topology. The structure of 2 reveals 2-D hybrid inorganic layer topology with large coordination spaces occupied by {Cu(Hpyr)(2)(H(2)O)(4)}(2+) ions. Compound 3 contains two types of cyanido-bridged 1-D chains of vertex-sharing squares linked together by formate ions in two directions forming hybrid inorganic-organic 3-D framework (I(1)O(2)). The magnetic measurements for 1-3 reveal a weak ferromagnetic coupling through Cu(II)-NC-W(V) bridges.     

Copper perchlorate and tetrafluoridoborate compounds with the ligand 1,4,5-triazanaphthalene. Gradual transformation of mononuclear Cu(II) compounds via polynuclear mixed-valence Cu(II)/Cu(I) species to dinuclear Cu(I); syntheses, characterizations and X-ray structures

When the ligand 1,4,5-triazanaphthalene (abbreviated as tan) is reacted with Cu(II) BF(4)(-) and ClO(4)(-) salts, a variety of mononuclear compounds has been found, all with the [Cu(tan)(4)] unit and varying amounts of weakly coordinating axial ligands and lattice solvents. Reproducible compounds formed include two purple compounds, analyzing as [Cu(tan)(4)](ClO(4))(2)(CH(3)OH)(2)(H(2)O) (1) and [Cu(tan)(4)](BF(4))(2)(CH(3)OH)(1.5)(H(2)O) (3), and two blue compounds, analyzing as [Cu(tan)(4)](ClO(4))(2)(H(2)O)(2) (2) and [Cu(tan)(4)](2)(BF(4))(2)(H(2)O)(2) (4). Upon standing at room temperature, red-coloured, mixed-valence dinuclear-based 3D coordination polymers are formed by conversion of the purple/blue products, of which [Cu(2)(tan)(4)](n)(BF(4))(3n) (5) and the isomorphic methanol-water adduct [Cu(tan)(4)](n)(BF(4))(3n)(CH(3)OH)(n)(H(2)O)(5n) (5A) are presented in this paper. In addition a fully reduced dinuclear Cu(I) compound of formula [Cu(2)(tan)(3)(ClO(4))(2)] (7) has been observed, and structurally characterized, as a rare three-blade propeller structure, with a Cu-Cu distance of 2.504 ?.     

Structure and magnetic properties of a giant Cu44II aggregate which packs with a zeotypic superstructure

Reaction of Cu(II) and the aminopolycarboxylate nitrilotripropionic acid (H(3)ntp) in water leads to the formation of [Cu(44)(mu(8)-Br)(2)(mu(3)-OH)(36)(mu-OH)(4)(ntp)(12)Br(8)(OH(2))(28)]Br(2).81H(2)O. The Cu(44) aggregates have a central inorganic core corresponding to [Cu(24)(mu(8)-Br)(2)(mu(3)-OH)(24)(mu-OH)(8)](14+) anchored on two bromide anions, and this is encased in a shell of Cu(II)/ligand units. The aggregates pack into a distorted tetragonal array with a very open structure containing large amounts of water of crystallization. The magnetic properties have been studied and, while complicated by the presence of low-lying excited states, indicate that the individual clusters have nonzero spin ground states.     

Solid-state coordination chemistry of the Cu/triazolate/X system (X = F-, Cl-, Br-, I-, OH-, and SO4(2-))

Hydrothermal reactions of 1,2,4-triazole with the appropriate copper salt have provided eight structurally unique members of the Cu/triazolate/X system, with X = F-, Cl-, Br-, I-, OH-, and SO4(2-). The anionic components X of [Cu3(trz)4(H2O)3]F2 (1) and [Cu6(trz)4Br]Cu4Br4(OH) (4) do not participate in the framework connectivity, acting as isolated charge-compensating counterions. In contrast, the anionic subunits X of [Cu(II)Cu(I)(trz)Cl2] (2), [Cu6(trz)4Br2] (3), [Cu(II)Cu(I)(trz)Br2] (5), [Cu3(trz)I2] (6), [Cu6(II)Cu2(I)(trz)6(SO4)3(OH)2(H2O)] (8), and [Cu4(trz)3]OH.7.5H2O (9.7.5H2O) are intimately involved in the three-dimensional connectivities. The structure of [Cu(II)Cu(I)(trz)2][Cu3(I)I4] (7) is constructed from two independent substructures: a three-dimensional cationic {Cu2(trz)2}n(n+) component and {Cu3I4}n(n-) chains. Curiously, four of the structures are mixed-valence Cu(I)/Cu(II) materials: 2, 5, 7, and 8. The only Cu(II) species is 1, while 3, 4, 6, and 9.7.5H2O exhibit exclusively Cu(I) sites. The magnetic properties of the Cu(II) species 1 and of the mixed-valence materials 5, 7, 8, and the previously reported [Cu3(trz)3OH][Cu2Br4] have been studied. The temperature-dependent magnetic susceptibility of 1 conforms to a simple isotropic model above 13 K, while below this temperature, there is weak ferromagnetic ordering due to spin canting of the antiferromagnetically coupled trimer units. Compounds 5 and 7 exhibit magnetic properties consistent with a one-dimensional chain model. The magnetic data for 8 were fit over the temperature range 2-300 K using the molecular field approximation with J = 204 cm(-1), g = 2.25, and zJ' = -38 cm(-1). The magnetic properties of [Cu3(trz)3OH][Cu2Br4] are similar to those of 8, as anticipated from the presence of similar triangular {Cu3(trz)3(mu3-OH)}(2+) building blocks. The Cu(I) species 3, 4, 6, and 9 as well as the previously reported [Cu(5)(trz)3Cl2] exhibit luminescence thermochromism. The spectra are characterized by broad emissions, long lifetimes, and significant Stokes' shifts, characteristic of phosphorescence.     

From discrete [Y(DMF)8][Cu4(mu3-I)2(mu-I)3I2] ion pairs to extended [Y(DMF)6(H2O)2][Cu7(mu4-I)3(mu3-I)2(mu-I)4(I)]1infinity and [Y(DMF)6(H2O)3][Cu(I)7Cu(II)2(mu3-I)8(mu-I)6]2infinity arrays by H-bond templating in a confined solvent-free environment

An ionic heterometallic species [Y(DMF)(8)][Cu(4)(micro(3)-I)(2)(micro-I)(3)I(2)](1) was isolated from a solution of CuI, NH(4)I and YI(3)(Pr(i)OH)(4) in DMF-isopropoxyethanol, and was converted in a confined environment by progressive substitution of the DMF ligands with water molecules first into a 1D zig-zag structure [Y(DMF)(6)(H(2)O)(2)][Cu(7)(micro(4)-I)(3)(micro(3)-I)(2)(micro-I)(4)(I)](1infinity)(2) and finally into a 2D sheet [Y(DMF)(6)(H(2)O)(3)][Cu(I)(7)Cu(II)(2)(micro(3)-I)(8)(micro-I)(6)](2infinity)(3) by H-bond templating.     

Bending, twisting, and breaking CuCN chains to produce framework materials: the reactions of CuCN with alkali-metal halides

The reactions of the low-temperature polymorph of copper(I) cyanide (LT-CuCN) with concentrated aqueous alkali-metal halide solutions have been investigated. At room temperature, KX (X = Br and I) and CsX (X = Cl, Br, and I) produce the addition products K[Cu(2)(CN)(2)Br].H(2)O (I), K(3)[Cu(6)(CN)(6)I(3)].2H(2)O (II), Cs[Cu(3)(CN)(3)Cl] (III), Cs[Cu(3)(CN)(3)Br] (IV), and Cs(2)[Cu(4)(CN)(4)I(2)].H(2)O (V), with 3-D frameworks in which the -(CuCN)- chains present in CuCN persist. No reaction occurs, however, with NaX (X = Cl, Br, I) or KCl. The addition compounds, I-V, reconvert to CuCN when washed. Both low- and high-temperature polymorphs of CuCN (LT- and HT-CuCN) are produced, except in the case of Cs[Cu(3)(CN)(3)Cl] (III), which converts only to LT-CuCN. Heating similar AX-CuCN reaction mixtures under hydrothermal conditions at 453 K for 1 day produces single crystals of I-V suitable for structure determination. Under these more forcing conditions, reactions also occur with NaX (X = Cl, Br, I) and KCl. NaBr and KCl cause some conversion of LT-CuCN into HT-CuCN, while NaCl and NaI, respectively, react to form the mixed-valence Cu(I)/Cu(II) compounds [Cu(II)(OH(2))(4)][Cu(I)(4)(CN)(6)], a known phase, and [Cu(II)(OH(2))(4)][Cu(I)(4)(CN)(4)I(2)] (VI), a 3-D framework, which contains infinite -(CuCN)- chains. After 3 days of heating under hydrothermal conditions, the reaction between KI and CuCN produces [Cu(II)(OH(2))(4)][Cu(I)(2)(CN)I(2)](2) (VII), in which the CuCN chains are broken into single Cu-CN-Cu units, which in turn are linked into chains via iodine atoms and then into layers via long Cu-C and Cu-Cu interactions.     

Heterobimetallic coordination polymers incorporating [M(CN)(2)](-) (M = Cu,Ag) and [Ag(2)(CN)(3)](-) units: increasing structural dimensionality via M-M' and M...NC interactions

A series of new heterometallic coordination polymers has been prepared from the reaction of metal-ligand cations and KAg(CN)(2) units. Many of these contain silver-silver (argentophilic) interactions, analogous to gold-gold interactions, which serve to increase supramolecular structural dimensionality. Compared to [Au(CN)(2)](-) analogues, these polymers display new trends specific to [Ag(CN)(2)](-), including the formation of [Ag(2)(CN)(3)](-) and the presence of Ag...N interactions. [Cu(en)(2)][Ag(2)(CN)(3)][Ag(CN)(2)] (1, en = ethylenediamine) forms 1-D chains of alternating [Ag(CN)(2)](-) and [Ag(2)(CN)(3)](-) units via argentophilic interactions of 3.102(1) A. These chains are connected into a 2-D array by strong cyano(N)-Ag interactions of 2.572(3) A. [Cu(dien)Ag(CN)(2)](2)[Ag(2)(CN)(3)][Ag(CN)(2)] (2, dien = diethylenetriamine) forms a 1-D chain of alternating [Cu(dien)](2+) and [Ag(CN)(2)](-) ions with the Cu(II) atoms connected in an apical/equatorial fashion. These chains are cross-linked by [Ag(2)(CN)(3)](-) units via argentophilic interactions of 3.1718(8) A and held weakly in a 3-D array by argentophilic interactions of 3.2889(5) A between the [Ag(CN)(2)](-) in the 2-D array and the remaining free [Ag(CN)(2)](-). [Ni(en)][Ni(CN)(4)].2.5H(2)O (4) was identified as a byproduct in the reaction to prepare the previously reported [Ni(en)(2)Ag(2)(CN)(3)][Ag(CN)(2)] (3). In [Ni(tren)Ag(CN)(2)][Ag(CN)(2)] (5, tren = tris(2-aminoethyl)amine), [Ni(tren)](2+) cations are linked in a cis fashion by [Ag(CN)(2)](-) anions to form a 1-D chain similar to the [Au(CN)(2)](-) analogue. [Cu(en)Cu(CN)(2)Ag(CN)(2)] (6) is a trimetallic polymer consisting of interpenetrating (6,3) nets stabilized by d(10)-d(10) interactions between Cu(I)-Ag(I) (3.1000(4) A). Weak antiferromagnetic coupling has been observed in 2, and a slightly stronger exchange has been observed in 6. The Ni(II) complexes, 4 and 5, display weak antiferromagnetic interactions as indicated by their relatively larger D values compared to that of 3. Magnetic measurements on isostructural [Ni(tren)M(CN)(2)][M(CN)(2)] (M = Ag, Au) show that Ag(I) is a more efficient mediator of magnetic exchange as compared to Au(I). The formation of [Ni(CN)(4)](2)(-), [Ag(2)(CN)(3)](-), and [Cu(CN)(2)](-) are all attributed to secondary reactions of the dissociation products of the labile KAg(CN)(2).     

3d-Metal derivatives of the [Cu(I)(SO3)4]7- ion: structure and magnetism

The Cu(SO(3))(4)(7-) anion, which consists of a tetrahedrally coordinated Cu(I) centre coordinated to four sulfur atoms, is able to act as a multidentate ligand in discrete and infinite supramolecular species. The slow oxidation of an aqueous solution of Na(7)Cu(SO(3))(4) yields a mixed oxidation state, 2D network of composition Na(5){[Cu(II)(H(2)O)][Cu(I)(SO(3))(4)]}·6H(2)O. The addition of Cu(II) and 2,2'-bipyridine to an aqueous Na(7)Cu(SO(3))(4) solution leads to the formation of a pentanuclear complex of composition {[Cu(II)(H(2)O)(bipy)](4)[Cu(I)(SO(3))(4)]}(+); a combination of hydrogen bonding and π-π stacking interactions leads to the generation of infinite parallel channels that are occupied by disordered nitrate anions and water molecules. A pair of Cu(SO(3))(4)(7-) anions each act as a tridentate ligand towards a single Mn(II) centre when Mn(II) ions are combined with an excess of Cu(SO(3))(4)(7-). An anionic pentanuclear complex of composition {[Cu(I)(SO(3))(4)](2)[Fe(III)(H(2)O)](3)(O)} is formed when Fe(II) is added to a Cu(+)/SO(3)(2-) solution. Hydrated ferrous [Fe(H(2)O)(6)(2+)] and sodium ions act as counterions for the complexes and are responsible for the formation of an extensive hydrogen bond network within the crystal. Magnetic susceptibility studies over the temperature range 2-300 K show that weak ferromagnetic coupling occurs within the Cu(II) containing chains of Na(5){[Cu(II)(H(2)O)][Cu(I)(SO(3))(4)]}·6H(2)O, while zero coupling exists in the pentanuclear cluster {[Cu(II)(H(2)O)(bipy)](4)[Cu(I)(SO(3))(4)]}(NO(3))·H(2)O. Weak Mn(II)-O-S-O-Mn(II) antiferromagnetic coupling occurs in Na(H(2)O)(6){[Cu(I)(SO(3))(4)][Mn(II)(H(2)O)(2)](3)}, the latter formed when Mn was in excess during synthesis. The compound, Na(3)(H(2)O)(6)[Fe(II)(H(2)O)(6)](2){[Cu(I)(SO(3))(4)](2)[Fe(III)(H(2)O)](3)(O)}·H(2)O, contained trace magnetic impurities that affected the expected magnetic behaviour.     

Fluorene-based Cu(II)-MOF: a visual colorimetric anion sensor and separator based on an anion-exchange approach

A new 2D Cu(II)-MOF generated from a fluorene-based ligand and Cu(NO(3))(2) was reported. It is an interesting visual colorimetric anion sensor. In addition, it can completely separate Cl(-)/Br(-), Br(-)/I(-) and SCN(-)/N(3)(-) anions under ambient conditions.     

Identification of a copper(I) intermediate in the conversion of 1-aminocyclopropane carboxylic acid (ACC) into ethylene by Cu(II)-ACC complexes and hydrogen peroxide

Several Cu(II) complexes with ACC (=1-aminocyclopropane carboxylic acid) or AIB (=aminoisobutyric acid) were prepared using 2,2'-bipyridine, 1,10-phenanthroline, and 2-picolylamine ligands: [Cu(2,2'-bipyridine)(ACC)(H2O)](ClO4) (1a), [Cu(1,10-phenanthroline)(ACC)](ClO4) (2a), [Cu(2-picolylamine)(ACC)](ClO4) (3a), and [Cu(2,2'-bipyridine)(AIB)(H2O)](ClO4) (1b). All of the complexes were characterized by X-ray diffraction analysis. The Cu(II)-ACC complexes are able to convert the bound ACC moiety into ethylene in the presence of hydrogen peroxide, in an "ACC-oxidase-like" activity. A few equivalents of base are necessary to deprotonate H2O2 for optimum activity. The presence of dioxygen lowers the yield of ACC conversion into ethylene by the copper(II) complexes. During the course of the reaction of Cu(II)-ACC complexes with H2O2, brown species (EPR silent and lambda max approximately 435 nm) were detected and characterized as being the Cu(I)-ACC complexes that are obtained upon reduction of the corresponding Cu(II) complexes by the deprotonated form of hydrogen peroxide. The geometry of the Cu(I) species was optimized by DFT calculations that reveal a change from square-planar to tetrahedral geometry upon reduction of the copper ion, in accordance with the observed nonreversibility of the redox process. In situ prepared Cu(I)-ACC complexes were also reacted with hydrogen peroxide, and a high level of ethylene formation was obtained. We propose Cu(I)-OOH as a possible active species for the conversion of ACC into ethylene, the structure of which was examined by DFT calculation.     

Syntheses, characterization, and luminescence of Pt II-M I (M = Cu, Ag, Au) heterometallic complexes by incorporating Pt(diimine)(dithiolate) with [M2(dppm)2]2+ (dppm = Bis(diphenylphosphino)methane)

Reaction of Pt(diimine)(edt) (edt = 1,2-ethanedithiolate) with M(2)(dppm)(2)(MeCN)(2)(2+) (dppm = bis(diphenylphosphino)methane) gave heterotrinuclear complexes [PtCu(2)(edt)(mu-SH)(dppm)(3)](ClO(4)) (11) and [PtCu(2)(diimine)(2)(edt)(dppm)(2)](ClO(4))(2) (diimine = 2,2'-bpyridine (bpy), 12; 4,4'-dibutyl-2,2'-bipyridine (dbbpy), 13; phenanthroline (phen), 14; 5-bromophenanthroline (brphen), 15) when M = Cu(I). The reaction, however, afforded tetra- and trinuclear complexes [Pt(2)Ag(2)(edt)(2)(dppm)(2)](SbF(6))(2) (17) and [PtAu(2)(edt)(dppm)(2)](SbF(6))(2) (21) when M = Ag(I) and Au(I), respectively. The complexes were characterized by elemental analyses, electrospray mass spectroscopy, (1)H and (31)P NMR, IR, and UV-vis spectrometry, and X-ray crystallography for 14, 17, and 18. The Pt(II)Cu(I)(2) heterotrinuclear complexes 11-15 exhibit photoluminescence in the solid states at 298 K and in the frozen acetonitrile glasses at 77 K. It is likely that the emission originates from a ligand-to-metal charge transfer (dithiolate-to-Pt) (3)[p(S) --> d(Pt)] transition for 11 and from an admixture of (3)[d(Cu)/p(S)-pi(diimine)] transitions for 12-16. The Pt(II)(2)Ag(I)(2) heterotetranuclear complexes 17 and 18 are nonemissive in the solid states and in solutions at 298 K but show photoluminescence at 77 K. The Pt(II)Au(I)(2) heterotrinuclear complexes 19-21, however, are luminescent at room temperature in the solid state and in solution. Compounds 19 and 20 afford negative solvatochromism associated with a charge transfer from an orbital of a mixed metal/dithiolate character to a diimine pi orbital.     

A Ferromagnetic Interaction between Cu(2+) Centers through a [CrO(4)](2-) Bridge: Crystal Structures and Magnetic Properties of [{Cu(acpa)}(2)(&mgr;-MO(4))] (M = Cr, Mo) (Hacpa = N-(1-Acetyl-2-propyridene)(2-pyridylmethyl)amine)

The reaction of [Cu(acpa)](+) with [MO(4)](2)(-) (Hacpa = N-(1-acetyl-2-propyridene)(2-pyridylmethyl)amine and M = Cr and Mo) in water-methanol or water-acetonitrile solution affords dinuclear copper(II) complexes with metalate bridges, [{Cu(acpa)}(2)(&mgr;-CrO(4))].4CH(3)OH.4H(2)O (1) and [{Cu(acpa)}(2)(&mgr;-MoO(4))].4H(2)O (2), respectively. The crystal structures and the magnetic properties have been studied. Complexes 1 and 2 are isomorphous and the structures are made up of discrete dimers in which two copper(II) ions are bridged by the [MO(4)](2)(-) anion. The coordination geometry about the copper(II) ions is square planar with a N(2)O chelate group from acpa and an oxygen atom from [MO(4)](2)(-). Magnetic susceptibility measurements for 1 revealed that a ferromagnetic interaction between copper(II) ions is propagated through the [CrO(4)](2)(-) bridge and the coupling constant (2J) was evaluated to be 14.6(1) cm(-)(1) (H = -2JS(1).S(2)). In 2, two copper(II) ions bridged by [MoO(4)](2)(-) anion are antiferromagnetically coupled with the 2J value of -5.1(4) cm(-)(1). The ferromagnetic interaction in 1 is explained by means of the orbital topology of frontier orbitals. Crystal data: 1, monoclinic, space group P2(1)/m, a = 8.349(2) ?, b = 17.616(3) ?, c = 10.473 ?, beta = 107.40(2) degrees, Z= 2; 2, monoclinic, space group P2(1)/m, a = 8.486(2) ?, b = 18.043(3) ?, c = 9.753(2) ?, beta = 95.82(2) degrees, Z = 2.     

Antiferromagnetic three-dimensional order induced by carboxylate bridges in a two-dimensional network of [Cu3(dcp)2(H2O)4] trimers

A new Cu(II) complex, [Cu(3)(dcp)(2)(H(2)O)(4)](n), with the ligand 3,5-pyrazoledicarboxylic acid monohydrate (H(3)dcp) has been prepared by hydrothermal synthesis, and it crystallizes in the monoclinic space group P2(1)/c with a = 11.633(2) A, b = 9.6005(14) A, c = 6.9230(17) A, beta = 106.01(2) degrees, and Z = 2. In the solid state structure of [Cu(3)(dcp)(2)(H(2)O)(4)](n), trinuclear [Cu(3)(dcp)(2)(H(2)O)(4)] repeating units in which two dcp(3-) ligands chelate the three Cu(II) ions with the central Cu(II) ion, Cu(1) (on an inversion center), link to form infinite 2D sheets via syn-anti equatorial-equatorial carboxylate bridges between Cu(2) atoms in adjacent trimers. These layers are further linked by syn-anti axial-equatorial carboxylate bridging between Cu(1) atoms in adjacent sheets resulting in the formation of a crystallographic 3D network. A detailed analysis of the magnetic properties of [Cu(3)(dcp)(2)(H(2)O)(4)](n) reveals that the dcp(3-) ligand acts to link Cu(II) centers in three different ways with coupling constants orders of magnitude apart in value. In the high temperature region above 50 K, the dominant interaction is strongly antiferromagnetic (J/k(B) = -32 K) within the trimer units mediated by the pyrazolate bridges. Below 20 K, the trimer motif can be modeled as an S = 1/2 unit. These units are coupled to their neighbors by a ferromagnetic interaction mediated by the syn-anti equatorial-equatorial carboxylate bridge. This interaction has been estimated at J(2D)/k(B) = +2.8 K on the basis of a 2D square lattice Heisenberg model. Finally, below 3.2 K a weak antiferromagnetic coupling (J(3D)/k(B) = -0.1 K) which is mediated by the syn-anti axial-equatorial carboxylate bridges between the 2D layers becomes relevant to describe the magnetic (T, H) phase diagram of this material.