trans-Di-aqua-bis-(pyridazine-3-carboxyl-ato-κ(2) N (2),O)cobalt(II) dihydrate

The title compound, [Co(C5H3N2O2)2(H2O)2]·2H2O, contains a Co(II) ion on an inversion center, exhibiting an octa-hedral coordination geometry. The equatorial plane is formed by two trans-related N,O-bidentate pyridazine-3-carboxyl-ate ligands and the axial positions are occupied by two water mol-ecules. The Co(II) complex mol-ecules are stacked in a column along the a-axis direction by an O-H⋯N hydrogen bond between the non-coordinating pyridazine N atom and the coordinating water mol-ecule. These columns are further connected into a layer parallel to the ac plane by additional hydrogen bonds involving the coordinating and non-coordinating water mol-ecules, and the non-coordinating carboxyl-ate O atom. The crystal packing is completed by inter-layer weak C-H⋯O inter-actions.

Diaqua-bis-(1H-imidazole-4-carboxyl-ato-κ(2)N(3),O)cobalt(II)

The title compound, [Co(C₄H₃N₂O₂)₂(H₂O)₂], contains a Co^II cation on a twofold rotation axis, exhibiting a distorted octa­hedral coordination geometry. The equatorial plane is formed by two N,O-bidentate 1H-imidazole-4-carboxyl­ate ligands and the axial positions are occupied by water mol­ecules. The crystal packing consists of a three-dimensional network stabilized by O—H⋯O and N—H⋯O hydrogen bonds, together with weak π–π inter­actions [centroid–centroid distance = 3.577 (2) Å] between the imidazole rings.

Tetra-kis(μ(2)-ferrocene-carboxyl-ato-κO:O')bis-[(methanol-κO)copper(II)] methanol disolvate

The complex mol­ecule of the title compound, [Cu₂Fe₄(C₅H₅)₄(C₆H₄O₂)₄(CH₃OH)₂]·2CH₃OH, lies about an inversion centre and contains two centrosymetrically related Cu^II atoms bridged by four O:O′-bidentante ferrocene­carboxyl­ate anions, leading to a dimeric tetra­bridged unit with a paddle-wheel geometry. The Cu^II atom has a distorted square-pyramidal coordination environment with four O atoms from four ferrocene­carboxyl­ate ligands in basal positions and an O atom from a methanol mol­ecule in an apical position. One of the two crystallographically independent ferrocenyl groups has a staggered conformation, while the other is eclipsed. The mol­ecules are connected into a chain along the b axis by O—H⋯O hydrogen bonds involving coordinated and uncoordinated methanol mol­ecules and the O atom from a ferrocene­carboxyl­ate unit.

Coexistence of Five Different Copper(II)−Phenanthroline Species in the Crystal Packing of Inorganic−Metalorganic Hybrids Based on Keggin Polyoxometalates and Copper(II)−Phenanthroline−Oxalate Complexes

Reaction of in situ generated copper(II)-monosubstituted Keggin polyoxometalates and copper(II)-phenanthroline-oxalato complexes in ammonium or rubidium acetate buffers led to the formation of the hybrid inorganic-metalorganic compounds E4[Cu(phen)(H2O)4]2[Cu4(phen)4(H2O)4(ox)3]0.6[Cu2(phen)2(H2O)4(ox)]0.4[Cu(phen)(ox)]0.8[{SiW11O39Cu(H2O)}2{Cu2(phen)2(ox)}].20H2O [E: Rb (1), NH4 (2)]. The two compounds have been characterized by means of elemental analysis, thermogravimetry, infrared and electron paramagnetic resonance spectroscopies, and magnetic susceptibility measurements, and their structures have been established by single-crystal X-ray diffraction. Both compounds are isostructural, and they contain a discrete bimolecular hybrid polyanion and several types of copper-phenanthroline complexes of variable nuclearity. The main structural features of these compounds are the presence of the new hybrid POM [{SiW11O39Cu(H2O)}2{Cu2(phen)2(mu-ox)}]10-, where the dinuclear copper-oxalato complex is sandwiched by two copper-monosubstituted POMs, and the coexistence of five different copper-phenanthroline species with nuclearities ranging from one to four.

Tetrahydroxy-p-benzoquinone as a Source of Polydentate O-Donor Ligands. Synthesis, Crystal Structure, and Magnetic Properties of the [Cu(bpy)(dhmal)]2 Dimer and the Two-Dimensional [{SiW12O40}{Cu2(bpy)2(H2O)(ox)}2]·16H2O Inorganic−Metalorganic Hybrid

The use of tetrahydroxy-p-benzoquinone as a slow source of dihydroxymalonato and oxalato ligands led to the isolation under open-air mild reaction conditions of five different compounds, two of them prepared for the first time: [Cu(bpy)(dhmal)]2 (1) and [{SiW12O40}{Cu2(bpy)2(H2O)(ox)}2].16H2O (5) (bpy, 2,2'-bipyridine; dhmal, dihydroxymalonate; ox, oxalate). A possible mechanism for the oxidation of the benzoquinone to give the croconate dianion, which undergoes further ring-opening oxidation to decompose into dihydroxymalonate and oxalate, is proposed. All compounds have been characterized by elemental analysis, thermogravimetry, infrared spectroscopy, and powder X-ray diffraction. Single-crystal X-ray diffraction, electron paramagnetic resonance, and magnetic susceptibility measurements have been performed for compounds 1 and 5. A complete band assignment of the experimental FT-IR spectra is given through comparison with the ones calculated using density functional theory (DFT). The neutral dimer 1 constitutes the first structurally characterized example of a transition metal-dhmal complex, and it contains two copper atoms bridged by two dihydroxymalonato ligands acting in a mu2-kappa3O,O',O":kappa1O coordination fashion, so that an equatorial-axial Cu2(mu2-O)2 rhomboid core is formed. On the other hand, the inorganic-metalorganic hybrid compound 5 shows a two-dimensional arrangement of Keggin polyanions linked by one of the Cu atoms of the oxalate cationic dimers to give layers parallel to the (10) plane, the remaining ox-Cu-bpy fragments acting as interlamellar separators. In both cases, magnetic and EPR results are discussed with respect to the crystal structure of the compounds and, for compound 1, also with respect to DFT calculations of the exchange coupling constant.

Synthesis, X-ray structures and luminescence properties of three multidimensional metal–organic frameworks incorporating the versatile 5-(pyrimidyl)tetrazolato bridging ligand

The hydrated sodium salt of the novel and versatile 5-(pyrimidyl)tetrazolato ligand (pmtz(-)), Na(pmtz).H(2)O (1), has been prepared in very mild conditions from 2-cyanopyrimidine and NaN(3). Two coordination polymers [Cd(pmtz)(2)]n (2)and [Cd(pmtz)(micro-Cl)(0.5)(micro-N(3))(0.5)(H(2)O)](n)(3), , have been synthesized from (1)under conventional or hydrothermal conditions, respectively, and fully characterized by single-crystal or powder X-ray diffraction methods. Compounds and consist of mono-dimensional polymeric chains, further stabilized by interchain pi-pi stacking and hydrogen bond interactions. Compound , containing octacoordinated Cd ions of crystallographic D(2) symmetry, exhibits neutral (4, 4) layers formed by square units of the metallacalix[4]arene type in 1,3-alternate conformation. Species , and display intense, room temperature, photoluminescence in the solid state.

Hybrid Inorganic−Metalorganic Compounds Containing Copper(II)-Monosubstituted Keggin Polyanions and Polymeric Copper(I) Complexes

Four hybrid inorganic-metalorganic compounds containing copper(II)-monosubstituted Keggin polyoxotungstates, K3[Cu(I)(4,4'-bpy)]3[SiW11Cu(II)O39].11H2O (1), (paraquat)3[SiW11Cu(II)O39].6H2O (2; paraquat = N,N'-dimethyl-4,4'-bipyridinium), K3[Cu(I)(4,4'-bpy)]3[GeW11Cu(II)O39].11H2O (3), and Na2[Cu(I)(4,4'-bpy)]3[PW11Cu(II)O39(H2O)].4H2O (4), have been synthesized under autogenous pressure hydrothermal conditions and characterized by elemental analysis and infrared spectroscopy (FT-IR). The crystal structures of 1, 2, and 4 have been established by single-crystal X-ray diffraction. The crystal packings are characterized by the presence of monodimensional extended entities: either the polymeric polyanion [SiW11CuO39]n(6n-) (2), the cationic [Cu(4,4'-bpy)]n(n+) chain (4), or both simultaneously as in compound 1, where the inorganic and metalorganic sublattices are mutually perpendicular. To asses the influence of packing in the copper(I) complex structural diversity found in compounds 1 and 4, a search in the CSD database has been performed and the resulting geometrical features have been analyzed and compared with experimental crystallographic data and DFT calculations.

Inorganic−Metalorganic Hybrids Based on Copper(II)-Monosubstituted Keggin Polyanions and Dinuclear Copper(II)−Oxalate Complexes. Synthesis, X-ray Structural Characterization, and Magnetic Properties

Reaction of in situ generated copper(II)-monosubstituted Keggin polyoxometalates and copper(II)-bipyridine-oxalate complexes in the corresponding alkaline acetate buffer led to the formation of hybrid metal organic-inorganic compounds K(2)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(H(2)O)(2)(mu-ox)}(2)].14H(2)O (1), K(14)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}](2)[SiW(11)O(39)Cu(H(2)O)].55H(2)O (2), (NH(4))(4)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}].10H(2)O (3), and Rb(4)[{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}].10H(2)O (4). Their structures have been established by single-crystal X-ray diffraction. The main structural feature of these compounds is the presence of copper(II)-monosubstituted alpha-Keggin polyoxoanions as inorganic building blocks, on which the mu-oxalatodicopper metalorganic blocks are supported. Compound 1contains the discrete hybrid polyanion [{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(H(2)O)(2)(mu-ox)}(2)](2)(-), whereas the polymeric hybrid polyanion [{SiW(11)O(39)Cu(H(2)O)}{Cu(2)(bpy)(2)(mu-ox)}(2)](n)(4)(n)(-) gives a monodimensional character to compounds 2-4. Magnetic and EPR results are discussed with respect to the crystal structure of the compounds. DFT calculations on both the [Cu(2)(bpy)(2)(H(2)O)(4)(mu-ox)](2+) cationic complex and the metalorganic blocks have been performed in order to determine the optimized geometry and the magnetic coupling constants, respectively.

Analysis of Weak Interactions in the Crystal Packing of Inorganic Metalorganic Hybrids Based on Keggin Polyoxometalates and Dinuclear Copper(II)−Acetate Complexes

Reaction of in situ generated copper-monosubstituted Keggin polyoxometalate (POM) and copper-phenanthroline complexes in potassium or sodium acetate buffers led to the formation of the potassium salt of [[SiW(11)O(39)Cu(H(2)O)][Cu(2)(phen)(2)(H(2)O)(ac)(2)]](4-) (1) and [[Si(2)W(22)Cu(2)O(78)(H(2)O)][u(2)(phen)(2)(H(2)O)(ac)(2)](2)](8-) (2, where phen = phenanthroline and ac = acetate) hybrid polyanions, respectively. Both compounds are the first discrete mono- and bimolecular transition-metal-substituted Keggin POMs that support a binuclear copper-acetate complex. Despite the different nature of the POMs, the crystal packing of the two compounds is closely related, being formed of hybrid parallel layers that give rise to an alternate sequence of inorganic and metalorganic regions. This packing type seems to be determined by the extensive network of weak intermolecular interactions established by the dicopper complexes, as a Hirshfeld surface analysis shows. Electron paramagnetic resonance studies indicate that both the supported [Cu(2)(ac)(2)(phen)(2)(H(2)O)](2+) complexes and the copper(II)-monosubstituted POMs are magnetically isolated.

Organic-Inorganic Hybrids Based on Novel Bimolecular [Si2W22Cu2O78(H2O)]12−Polyoxometalates and the Polynuclear Complex Cations [Cu(ac)(phen)(H2O)]nn+(n=2, 3)

The reaction of a monosubstituted Keggin polyoxometalate (POM) generated in situ with copper-phenanthroline complexes in excess ammonium or rubidium acetate led to the formation of the hybrid metal organic-inorganic compounds A7[Cu2(ac)2(phen)2(H2O)2][Cu3(ac)3(phen)3(H2O)3][Si2W22Cu2O78(H2O)].approximately 18 H2O (A=NH4+ (1), Rb+ (2); ac=acetate; phen=1,10-phenanthroline). These compounds are constructed from inorganic and metalorganic interpenetrated sublattices containing the novel bimolecular Keggin POM, [Si2W22Cu2O78(H2O)]12-, and Cu-ac-phen complexes, [Cu(ac)(phen)(H2O)]n n+ (n=2, 3). The packing of compound 1 can be viewed as a stacking of open-framework layers parallel to the xy plane built of hydrogen-bonded POMs, and zigzag columns of pi-stacked Cu-ac-phen complex cations running along the [111] direction. Magnetic and EPR results are discussed with respect to the crystal structure of the compounds. DFT calculations on [Cu(ac)(phen)(H2O)]n n+ cationic complexes have been performed, to check the influence of packing in the complex geometry and determine the magnetic exchange pathways.

A Novel Hybrid Inorganic–Metalorganic Compound Based on a Polymeric Polyoxometalate and a Copper Complex: Synthesis, Crystal Structure and Topological Studies

Reaction of monosubstituted Keggin polyoxometalates (POMs) and [Cu(ac)(pmdien)]+ generated in situ led to the formation of the hybrid metal organic-inorganic compound K5[Cu(ac)(pmdien)][SiW11CuO39].12H2O; its crystal structure and magnetic properties have also been determined. The packing of this compound can be viewed as a stacking of hydrogen-bonded chiral double chains, with the cationic complexes located between the two-dimensional arrangement of POM double chains. DFT calculations performed on [Cu(ac)(pmdien)]+ suggest that the distortion presented in this cationic copper complex is due to electronic effects. An AIM stability study of the cationic copper complex, in order to determine the relationship between the bond angle Cu-O-C and the denticity of the acetate ligand, has been carried out. Topological analyses over the polyhedral distortion, both of the monosubstituted polyanion and copper complexes, have been performed by means of continuous shape measures (CSM).

A novel organic-inorganic hybrid based on a dinuclear copper complex supported on a keggin polyoxometalate

The autoassembly process of copper-oxalate dimers and Keggin type polyoxometalates leads to the first example of a new family of organic-inorganic hybrids, K(14)[(Cu(2)(bpy)(2)(mu-ox))(SiW(11)O(39)Cu(H(2)O))](2)[SiW(11)O(39)Cu(H(2)O)]. approximately 55H(2)O. This compound crystallizes in the monoclinic space group C2/m, a = 37.932(6) A, b = 21.303(3) A, c = 12.546(2) A, beta = 106.16(1) degrees, Z = 2. The crystal structure reveals the presence of a polymeric hybrid built up of alternating dimer and polyoxometalate entities.

Water displacement by cyanogold complexes in binuclear nickel(II) compounds based on bridging oxalate. Synthesis, structural diversity, magnetic properties, and DFT calculations

Several cyanogold complexes react with the binuclear nickel complex [(Ni(dien)(H(2)O))(2)(mu-ox)](PF(6))(2).2H(2)O to give the compounds [(Ni(dien)(H(2)O))(2)(mu-ox)]Br(2) (1), [(Ni(dien)(Au(CN)(2)))(2)(mu-ox)] (2), and [(Ni(dien))(2)(mu-ox)(mu-Au(CN)(4))](PF(6)) (3) (dien, diethilenetriamine; ox, oxalate). In the case of compounds 2 and 3, water displacement by the corresponding cyanogold complex takes place, whereas compound 1 is formed by a substitution of the anion. The crystal structures of compounds 1 and 2 present a 2D arrangement where the layers are connected by van der Waals forces (1) or N-H.Ntbd1;C hydrogen bonds (2), where each binuclear complex is hydrogen bonded to its neighbors, whereas compound 3 presents a novel structure where the tetracyanoaurate acts as a bridging ligand to give a polymeric compound. Magnetic studies of these compounds reveal an antiferromagnetic behavior. Finally, density functional theory (DFT) calculations have been performed on isolated models of compounds 2 and 3 in order to gain some insight about the different behavior of the [Au(CN)(2)](-) and [Au(CN)(4)](-) groups as ligands and proton acceptors in hydrogen bonds.

Tetracyanometalates of Ni, Pd, and Pt with cyclic diquaternary cations of 2,2'-bipyridine and 1,10-phenanthroline. A vibrational, crystallographic, and theoretical study of intermolecular weak interactions

The compounds (bpy-dq)[Ni(CN)(4)].2H(2)O (1), (bpy-dq)[Pd(CN)(4)].2H(2)O (2), and ((bpy-dq)[Pt(CN)(4)].2H(2)O (3) (bpy-dq = (C(12)H(12)N(2))(2+), 6,7-dihydrodipyrido[1,2-a:2',1'-c]pyrazinediium) and (phen-dq)[Ni(CN)(4)] (4), (phen-dq)[Pd(CN)(4)].H(2)O (5), and (phen-dq)[Pt(CN)(4)].H(2)O (6) (phen-dq = (C(14)H(12)N(2))(2+), 5,6-dihydropyrazino[1,2,3,4-lmn]-1,10-phenanthrolinediium) have been synthesized and characterized by X-ray diffraction. The three bipyridinium diquaternary salt derivatives are isostructural. The crystal structures of these dihydrated compounds consist of columns formed by alternating anion complexes and diquaternary cations, pi-pi interacting through cyanide ligands and the aromatic rings, and stabilized by an extended hydrogen-bond network. On the other hand, the packing in the phenanthrolinium diquaternary salt derivatives is strongly dependent on the hydration degree. Thus, the anhydrous [Ni(CN)(4)](2-) compound presents a laminar arrangement and the hydrated salts show a columnar packing, similar but not the same as compounds 1-3. The anhydrous form of compound 5 is isostructural with compound 4. Vibrational (IR, Raman) and thermogravimetric studies of these compounds have been carried out. Finally, DFT calculations have been performed on the isolated tetracyanometalate anions and diquaternary cations to assign the fundamental modes in the vibrational spectra. The intermolecular weak interactions were studied through the analysis of the charge density by using the theory of atoms in molecules (AIM).

(Mu-oxalato-O1,O2:O1',O2')bis[aqua(diethylenetriamine)nickel(II)] bis(hexafluorophosphate) dihydrate

The title compound, [Ni(2)(C(2)O(4))(C(4)H(13)N(3))(2)(H(2)O)(2)](PF(6))(2).2H(2)O, contains a dinuclear oxalato-bridged nickel(II) complex cation. The structure determination reveals the presence of a centrosymmetric binuclear complex where the oxalate ligand is coordinated in a bis-bidentate mode to the Ni atoms. The distorted octahedral environment of each Ni atom is completed by the three N atoms of the diethylenetriamine ligand in a fac arrangement and by one O atom from a water molecule. PF(6)(-) acts as counter-anion. A two-dimensional network of hydrogen bonds links the cations and anions and stabilizes the structure.

Ion-Pair Charge-Transfer Complexes Based on (o-Phenylenebis(oxamato))cuprate(II) and Cyclic Diquaternary Cations of 1,10-Phenanthroline and 2,2'-Bipyridine: Synthesis, Crystal Structure, and Physical Properties

The ion pair charge-transfer (IPCT) complexes (C(14)H(12)N(2))[Cu(opba)].3H(2)O (1) and Na(2)(C(12)H(12)N(2))[Cu(opba)](2).4H(2)O (2), opba = o-phenylenebis(oxamate), have been isolated. Both compounds crystallize in the triclinic space group P&onemacr;. Crystal data for the compounds 1, a = 7.3216(13) Å, b = 10.1756(9) Å, c = 16.4890(16) Å, alpha = 107.786(8) degrees, beta = 94.79(1) degrees, gamma = 104.16(1) degrees, V = 1117.4(3) Å(3), Z = 2, R = 0.033 for 5332 observed reflections with I > 3sigma(I); 2, a = 6.732(3) Å, b = 11.169(3) Å, c = 12.126(2) Å, alpha = 111.01(2) degrees, beta = 102.71(3) degrees, gamma = 93.57(3) degrees, V = 820.1(5) Å(3), Z = 2, R = 0.065 for 3354 observed reflections with I > 3sigma(I). The crystal structures consist of alternated anion complex and diquaternary cation layers pi-pi interacting through the corresponding aromatic rings. The metallic layers contain the [Cu(opba)](2)(4)(-) dimeric group where the copper(II) ions are in square-pyramidal environment. For both compounds an ion-pair charge-transfer (IPCT) band is observed at 517 nm. Their thermal behavior has also been explained on the basis of the different crystal arrangements. The dimeric nature of compound 1 is clearly confirmed by the observation of temperature-dependent ESR transitions between its singlet and triplet states. The |J| value, determined from the positions of these transitions, is 0.085 cm(-)(1) at room temperature and increases notably with decreasing temperature being 0.14 cm(-)(1) at 4.2 K. Comparison of these exchange constants with those observed for other carboxylate-bridged copper compounds allow us to deduce that the temperature dependence of J is due to lattice shrinkage leading to appreciable change of the Cu-O(ap) distance. The ESR spectrum of compound 2 is characteristic of an axial g-tensor with g( parallel) = 2.178 and g( perpendicular) = 2.049, showing a weak half-field DeltaM(s) = 2 transition in agreement with the dimeric nature of the complex. The thermal evolution of the magnetic susceptibility corresponds to a compound with weak antiferromagnetic interactions. The best fit of the magnetic data to a dimer S = (1)/(2) model gives J = -0.8 cm(-)(1), in good agreement with the topology of the bridging unit with the magnetic orbitals in parallel planes and a Cu-O-Cu angle of 95.4 degrees.