A two-dimensional bimetallic oxide constructed from ζ-octamolybdate clusters and Ag(I)-tpyprz cationic polymer components (tpyprz = tetra-2-pyridylpyrazine)

The hydrothermal reaction of Na₂MoO₄, Ag(CH₃CO₂), tetra-2-pyridylpyrazine (tpyprz), HF and water at 170 °C for 48 h yields [ Ag₄(tpyprz)₂(H₂O) Mo₈O₂₆] (1) as colorless plates. The structure of 1 is a two-dimensional network, constructed from Ag₄(tpyprz)₂(H₂O) ⁴ⁿ⁺_n chains linked through ζ- clusters. The chains exhibit three distinct Ag(I) environments: a four coordinate AgN₄ site, a three coordinate AgN₂O_aqua site, and four coordinate AgN₃O_oxo site which links to the molybdate cluster. Each cluster is connected by bridging oxo-groups to two silver/tpyprz chains to form the network architecture. Crystal data: C₂₄H₁₇Ag₂Mo₄N₆O_13.5, fw 1204.94, orthorhombic Pccn, a=20.8234(9) Å, b=14.5076(6) Å, c=20.3537(9) Å, V=6148.9(5) Å³, Z=8, D_calc=2.603 g cm⁻³.     

The preparation of dimolybdenum(V,V) complexes from molybdenum quadruply bonded metal-metal dimers

Oxidation of quadruply bonded metal-metal dimers in the presence of good π-accepting ligands results in the formation of Mo^V---Mo^V compounds of the type [MO₂(μ-X)₂(Y)(Y′)]²⁺ (X = O or S; Y,Y′ = O,O; S,S; O,S). Reaction of MO₂(O₂CCH₃)₄ with oxygen in the presence of Na₂mnt (mnt = 1,2-dicyanoethylene-2,2-dithiolate) gives [MO₂(μ-S)₂(O)(S)(mnt)₂]²⁻ (1). The compound crystallizes in the monoclinic space group P2₁/c, with cell dimensions a = 19.547(4), b = 15.210(4), c = 18.754(6) Å, β = 101.69(2)°, V= 5460(2) ų, and Z = 4. Similarly, oxidation of o-dichlorobenzene solutions of Mo₂Cl₄(CH₃CN)₄ and 4,4′-dimethyl-2,2′-dipyridyl (dmpby) or, more directly, the reaction of Mo₂Cl₄(dmbpy)₂ with oxygen leads to the formation of a red solid, which was characterized by X-ray crystallography to be Mo₂(μ-O)₂(O)₂(Cl)₂(dmbpy)₂ (2). Red diamond crystals, prepared by slow evaporation of CH₃CN solutions of 2, are trigonal and in the space group P3₁21 with cell dimensions a = 16.135(4), b = 16.135(4), c = 10.709(3) Å, V = 2414.4(13) ų and Z = 3. In both structures, the geometry about each of the molybdenum atoms is a distorted square pyramid with terminal oxygen or sulphur atoms at the apices and in a syn conformation. The molybdenum-molybdenum bond distances of 2.858(1) Å and 2.562(2) Å in structures of 1 and 2, respectively, are typical of other Mo^V---Mo^V dimers and indicative of a single Mo---Mo bond.     

Diamine incorporated compounds derived from polymeric nickel(II) fumarates and oxalates: Crystal structure, spectral and thermal properties of [Ni(en)3](O2CCHCHCO2)·3H2O and [Ni(en)3](O2CCO2)

Lewis-base mediated fragmentation of polymeric nickel(II) fumarate and oxalate are attempted using chelating σ-donor diamines like ethylenediamine (en) and 1,3-diaminopropane (dap) in various conditions which yielded [Ni(en)₃](fum)·3H₂O (1), [Ni(en)₃](ox) (2), [Ni(dap)₂(fum)] (3) and [Ni(dap)(ox)]·2H₂O (4). While 1 and 2 are molecular products each containing octahedral [Ni(en)₃]²⁺ moieties and the anionic dicarboxylate species, 3 and 4 are dap-incorporated polymeric products. The fumarate derivative 1 containing [Ni(en)₃]²⁺ moieties crystallizes in the monoclinic space group C2/c with a = 17.899(4) Å, b = 11.747(2) Å, c = 10.748(2) Å, β = 125.59(3)°, V = 1837.7(6) ų, Z = 4, while the oxalate analogue 2 is seen to be in the trigonal space group P−31c with a = 8.8770(13) Å, b = 8.8770(13) Å, c = 10.482(2) Å, γ = 120°, V = 715.3(2) ų, Z = 2. The octahedral [Ni(en)₃] units in both 1 and 2 are seen to be strongly H-bonded to the dicarboxylate moieties through the coordinated en units leading to a three-dimensional network. However, in 1 the water molecules also take part in the H-bonding and contribute to the overall 3D structure. In both 1 and 2 the crystal packing is done with the [Ni(en)₃]²⁺ units with absolute configuration Λ(δδδ) and its mirror conformer with Δ configuration in exactly equal numbers. Spectral (IR and UV–Visible) and magnetic measurements were carried out and some of the ligand-field parameters like D_q, B and β were evaluated for all the four compounds. These values suggest the presence of octahedrally coordinated nickel(II) in all the four complexes. Spectral data suggest that 3 has the two chelating dap moieties and the fumarate coordinated in η¹ form through both its carboxylate moieties while 4 has one chelating dap and the oxalate moiety coordinated in η⁴-bis-chelating form. Though both 1 and 2 are made of the same type of [Ni(en)₃]²⁺ units their thermograms give entirely different thermal features; 1 showing three clearly successive and step-wise dissociation of each en unit while 2 having a combined loss of two en units in the first thermal step. The relevant thermodynamic and kinetic parameters like E_a and ΔS also could be evaluated for various thermal steps for the compounds 1–4 using Coats–Redfern equation.     

Role of ligand conformation in the structural diversity of copper(II) and silver(I) coordination polymers containing the angular dipyridyl ligand bearing amide spacer

The new dipyridyl ligands N,N′-(methylenedi-p-phenylene)bis(pyridine-4-carboxamide), L1, and N,N′-(methylenedi-p-phenylene)bis(pyridine-3-carboxamide), L2, incorporating amide spacers have been synthesized and reacted with metal salts to give complexes of the types [Cu(L1)₂X₂]_∞ (X = Cl, 1 and X = Br, 2), {[Cu(L1)₂(DMF)](NO₃)₂}_∞, 3, {[Ag₂(L1)₂](SO₄)}_∞, 4, and {[Cu(L2)(DMSO)₂(NO₃)](NO₃)}_∞, 5. All compounds have been characterized by spectroscopic methods and their structures determined by X-ray crystallography.Complexes 1, 2 and 3 form 1-D double-stranded polymeric chains showing rhombic molecular squares with approximate dimensions of 16.95 × 19.13 Å² for 1, 17.03 × 19.06 Å² for 2 and 16.66 × 19.94 Å² for 3. Complex 4 forms infinite 1-D zigzag polymeric chains, which are interlinked through a series of Ag–O interactions to form wavy 1-D ladder like chains, and complex 5 forms 1-D sinusoidal chains. While the L1 ligands in complexes 1, 2 and 3 adopt the cis conformation and that in complex 4 adopts trans conformation, the L2 ligand in complex 5 adopts the trans-anti conformation. The ligand conformations also differ in the dihedral angles between the pyridyl and phenyl rings. All complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π → π* transition.     

Oligomerization and structural variation of alkali metal silyloxides

Lithium and potassium silyloxide complexes [Li(OSiPh₃)]_n (1), [K(thf)_0.2 (OSiPh₃)]_n (3) and [K(OSiMe₂^tBu)]_n (6) were prepared by deprotonation of HOSiPh₃ or HOSiMe₂^tBu with [Li(ⁿBu)] in hexane or KH in THF, respectively. Crystalline DME adducts [Li(μ-OSiPh₃)(η²-DME)]₂ (2) and [K₄(μ₃-OSiPh₃)₃(μ₃-OSiPh₂(η¹-Ph))(η²-DME)]₂ (μ-DME) (4) were prepared by dissolving 1 or 3, respectively, in dimethoxyethane followed by precipitation with alkane. The potassium-sequestered complexes [K(18-crown-6) (OSiPh₃)]₂ (5) and [K(18-crown-6)(OSiMe₂^tBu)]_n (7) were prepared from 3 or 5, respectively, and one equiv. of 18-crown-6 ether. The complexes were characterized by single-crystal X-ray diffraction: [Li(μ-OSiPh₃)(η²-DME)]₂ (2): a dimer featuring tetrahedral lithium centres linked by bridging —OSiPh₃ ligands. [Crystal data ( − 156°C): space group P , a = 14.238(6), b = 15.182(7), c = 11.796(5) Å, α = 110.57(2), β = 112.02(2), γ = 63.02(1) Å, V = 2055.33 ų, Z = 2.] [K₄(μ₃-OSiPh₃)₃{μ₃-OSiPh₂(η¹-Ph)}(η²-DME)]₂(μ-DME) (4): (1) two cubanes each having every potassium vertex chemically distinct; (2) one chelating DME ligand, one DME ligand bridging between two cubanes; and (3) a K-ipso-phenyl carbon contact. [Crystal data ( − 133°C): a = 14.246(4), b = 30.939(9), c = 17.981(5) Å, β = 112.33(1)° with Z = 2 in space group P2₁/c.] [K(18-crown-6)OSiPh₃]₂ (5): A dimer with slipped face-to-face stacking of the quasi-planar K(18-crown-6)⁺ part of the two Ph₃SiOK(18-crown-6) molecules; these are linked by a dative bond from one ether oxygen of a given crown to potassium contained in the other crown. [Crystal data ( − 155°C): a = 9.324(2), b = 17.640(5), c = 18.148(15) Å, β = 91.60(1)° with Z = 4 in space group P2₁/c.]     

Syntheses, crystal structures and spectroscopic properties of KEu[AsS4], K3Dy[AsS4]2 and Rb4Nd0.67[AsS4]2

Three rare earth compounds, KEu[AsS₄] (1), K₃Dy[AsS₄]₂ (2), and Rb₄Nd_0.67[AsS₄]₂ (3) have been synthesized employing the molten flux method. The reactions of A₂S₃ (A = K, Rb), Ln (Ln = Eu, Dy, Nd), As₂S₃, S were accomplished at 600 °C for 96 h in evacuated fused silica ampoules. Crystal data for these compounds are: 1, monoclinic, space group P2₁/m (no. 11), a = 6.7276(7) Å, b = 6.7190(5) Å, c = 8.6947(9) Å, β = 107.287(12)°, Z = 2; 2, monoclinic, space group C2/c (no. 15), a = 10.3381(7) Å, b = 18.7439(12) Å, c = 8.8185(6) Å, β = 117.060(7)°, Z = 4; 3, orthorhombic, space group Ibam (no. 72), a = 18.7333(15) Å, b = 9.1461(5) Å, c = 10.2060(6) Å, Z = 4. 1 is a two-dimensional structure with ²_∞[Eu(AsS₄)]⁻ layers separated by potassium cations. Within each layer, distorted bicapped trigonal [EuS₈] prisms are linked through distorted [AsS₄]³⁻ tetrahedra. Each Eu²⁺ cation is coordinated by two [AsS₄]³⁻ units by edge-sharing and bonded to further two [AsS₄]³⁻ units by corner-sharing. Compound 2 contains a one-dimensional structure with ¹_∞[Dy(AsS₄)₂]³⁻ chains separated by potassium cations. Within each chain, distorted bicapped trigonal prisms of [DyS₈] are linked by slightly distorted [AsS₄]³⁻ tetrahedra. Each Dy³⁺ ion is surrounded by four [AsS₄]³⁻ moieties in an edge-sharing fashion. For compound 3 also a one-dimensional structure with ¹_∞[Nd₀.₆₇(AsS₄)₂]⁴⁻ chains is observed. But the Nd position is only partially occupied and overall every third Nd atom is missing along the chain. This cuts the infinite chains into short dimers containing two bridging [As₄]³⁻ units and four terminal [AsS₄]³⁻ groups. 1 is characterized with UV/vis diffuse reflectance spectroscopy, IR, and Raman spectra.     

[As(V)As(III)O6]: An uncommon anion group in the crystal structure of K2Cu3(As2O6)2

The crystal structure of K₂Cu₃(As₂O₆)₂ was determined from single-crystal X-ray data by a direct method strategy and Fourier summations [a = 10.359(4) Å, B = 5.388(2)Å, C = 11.234(4) Å, β = 110.48(2)°; space group C2/m; Z = 2; R_w = 0.025 for 1199 reflections up to sin /λ = 0.81 Å⁻¹]. In detail, the structure consists of As(V)O₄ tetrahedra and As(III)O₃ pyramids linked by a common O corner atom to [As(V)As(III)O₆]⁴⁻ groups with symmetry m. The bridging bonds As(V)---O [1.749(3) Å] and As(III)---O [1.838(2) Å] are definitely longer than the other As(V)---O bonds [mean 1.669 Å] and As(III)---O bonds [1.764(2) Å, 2×]. The angle As(V)---O---As(III) is 123.0(1)°. The Cu atoms are [4 + 2]- and [4 + 1]-, and the K atom is [9]-coordinated to oxygen atoms. The As₂O₆ groups and the Cu coordination polyhedra are linked to sheets parallel to (001). These sheets are connected by the K atoms. Single crystals of K₂Cu₃(As₂O₆)₂ suitable for X-ray work were synthesized under hydrothermal conditions.     

t-Butyl isocyanide complexes of rhenium(I), chromium(O), tungsten(O,I) and platinum(II); X-ray crystal structures of bis(t-butylisocyanide)- tris(trimethylphosphine)chlororhenium(I) and tris(t-butylisocyanide)bis(trimethyl- phosphine)chlororhenium(I)

The reduction of ReCl₄(THF)₂ in the presence of excess t-butylisocyanide by sodium amalgam produces pentakis(t-butylisocyanide)chlororhenium(I), which has been converted to the corresponding methyl and ethyl derivatives. The reaction of pentakis(trimethylphosphine)chlororhenium(I) with Bu^tNC gives partially substituted complexes, ReCl(CNBu^t)₂(PMe₃)3 and ReCl(CNBu^t)₃(PMe₃)₂. The structures of both compounds have been determined by X-ray methods. Octahedral ReCl(CNBu^t)₂(PMe₃)₃ has trans isocyanide groups with one linear [C---N---C = 175(1)°] and one slightly bent [C---N---C = 159(1)°]. The Re---C bond lengths are equal within experimental error [2.004(7), 2.003(7)Å]. In the octahedral ReCl(CNBu^t)₃(PMe₃)₂, for which the structure is not well defined, due to disorder, the unique isocyanide trans to chlorine is considerably bent at the nitrogen atom [C--- ---C = 141(6)°] and appears to show the shortest Re---C bond length, 1.94(5) vs 2.02(5)Å for the other two isocyanides which are mutually trans. Protonation of these two isocyanide complexes with fluoroboric acid gives, respectively, the salts [ReCl(CNBu^t)CNHBu^t(PMe₃)₃]BF₄ and [ReCl(CNBu^t)₂CNHBu^t(PMe₃)₂]BF₄, whose configurations have been determined by NMR spectroscopy. The reduction by sodium amalgam of Cr₂(CO₂Me)₄ in tetrahydrofuran in presence of Bu^tNC gives a high yield of Cr(CNBu^t)₆ while similar reduction of the dimeric tungsten(II) complex of the anion (mhp) of 2-methyl-6- hydroxypyridine gives W(CNBu^t)₆. Interaction of W₂(mhp)₄ in methanol-ether with Bu^tNC gives a tungsten(I) complex W₂(η-mhp)₂(Bu^tNC)₄, which may be an intermediate in the reductive cleavage reaction. Interaction of cis-PtMe₂(PMe₃)₂ with Bu^tNC leads only to replacement of one PMe₃ group to give the complex cis-PtMe₂(PMe₃)(CNBu^t).     

Crystal chemistry of three new monodimensional fluorometalates templated with ethylenediamine

Three new monodimensional hybrid metal (Ti, In, Al) fluorides are synthesized with ethylenediamine (en) as a templating agent in solvothermal conditions assisted by microwave heating. All structures involve inorganic chains built up from TiO₂F₄ octahedra connected by two opposite O²⁻ vertices in [H₂en]·(TiOF₄) (I), from InF₆(H₂O) pentagonal bipyramids linked by F–F edges in [H₂en]·(InF₄(H₂O))₂·H₂O (II) and from (Al₇F₃₀)⁹⁻ polyanions sharing two opposite AlF₆ octahedra in [H₂en]₃·(Al₆F₂₄) (III). I is tetragonal, P4/ncc, a = 12.761(3) Å, c = 8.041(3) Å; II is orthorhombic, F2dd, a = 6.904(5) Å, b = 16.559(5) Å, c = 19.777(4) Å and III is monoclinic, P2₁/n, a = 9.387(2) Å, b = 6.710(2) Å, c = 21.513(6) Å, β = 97.18(3)°.     

Chains,helices, sheets and unusual 3D nets: Diverse structures of the flexible,ditopic ligand 1,2-bis(3-(4-pyridyl)pyrazolyl)ethane

The flexible ditopic ligand 1,2-bis(3-(4-pyridyl)pyrazol-1-yl)ethane (L^4Et) displays remarkable versatility in the complexes that it forms with transition metals with products ranging from 1D chains to interpenetrating 3D networks. The L^4Et ligand itself crystallises in the space group P2₁, adopting a helical twist, although it is found in a variety of other conformations in its complexes. Coordination polymers containing the L^4Et ligand vary from almost straight, parallel 1D chains of [Ag₂(L^4Et)₂(ClO₄)₂(DMF)]·DMF (1), through interdigitating helical complexes containing tetrahedral Zn(II), [Zn(NCS)₂(L^4Et)]·DMF·H₂O (2) to 2D sheets of [Cu(L^4Et)₂(H₂O)₂](PF₆)₂·xH₂O (3) and the three-fold interpenetrating 3D network of [Co(L^4Et)₂(NCS)₂] (4). The 3D network adopts an unusual 3D 4-connected dmp (6⁵.8) topology. Dimensionality can be limited by the use of chelating co-ligands, demonstrated by the formation of the dinuclear complex [{Cu(py-2,6-CO₂)(H₂O)}₂(L^4Et)] (5).     

Synthesis,spectroscopy and structures of halogen and sulfur-bridged dinuclear silver(I) complexes with N1-substituted thiophene-2-carbaldehyde thiosemicarbazone

The reactions of silver(I) halides (Cl or Br) with thiophene-2-carbaldehyde N¹-methyl thiosemicarbazone (HttscMe) in the presence of Ph₃P (1:1:1 molar ratio) yield halogen-bridged dimers, [Ag₂(μ-X)₂(η¹-S-HttsMe)₂(PPh₃)₂] (X = Cl, 1; Br, 2). The use of 2,2′-bipyridine in lieu of Ph₃P in the reaction of silver(I) chloride with HttscMe yields the sulfur-bridged dimer, [Ag₂(μ-S-HttscMe)₂(η¹-HttsMe)₂] · 2CHCl₃ 3. The substituents have altered the nature of bridge between the two silver atoms. The Ag···Ag separation (3.4867(5) Å) in complex 3 is less than that in the halogen-bridged dimers (3.734(4) Å 1; 3.746(5) Å 2). Unlike PPh₃ the co-ligand 2,2′-bipyridine did not coordinate to the silver center, but was necessary for crystallization in the reaction with the thio-ligand. NMR spectroscopy revealed that the complexes remained unchanged in the solution state (CDCl₃).     

Trimethylphosphite stabilized disilver(I) methanedisulfonates as MOCVD precursors

New disilver(I) methanedisulfonates complexes {CH₂(SO₃)₂Ag₂·[P(OMe)₃]_n} (n = 2, 2a; n = 4, 2b; n = 6, 2c) were prepared by reacting [CH₂(SO₃)₂Ag₂], which could be synthesized from methanedisulfonic acid and Ag₂CO₃ in water, with trimethylphosphite in dichloromethane. The molecular structure of 2a was determined using X-ray single crystal analysis. Complex 2a exhibits an infinite chain structure with eight-membered rings (AgOSOAgOSO) fully interconnected by the third sulfonic O atoms. Complex 2b was used to deposit silver films by metal organic chemical vapor deposition (MOCVD) for the first time. The silver film obtained was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersion X-ray analysis (EDX).     

Novel M(II)–Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu, Ni, Co) and HgCl2

A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)₂HgCl₂ (4), [Co(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.61H₂O (5) and [Ni(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.77H₂O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂(M=Cu(II), Co(II), Ni(II)), with HgCl₂. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) ų, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P , with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) ų, Z=1. Compound 6 also crystallized in the triclinic space group P , with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) ų, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)M(II)Hg(II) units are connected by Hg₂Cl₂ linkages to produce a novel M(II)–Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂ (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl₂ depending on the metal cation contained within them.     

Synthesis, properties and structures of the two “electron rich” cobalt-sulphur clusters [Co6(μ3-S)8(PEt3)6]

The reaction of hydrogen sulphide with [Co(H₂O)₆](BF₄)₂ and triethylphosphine in the presence of sodium tetraphenylborate or tetrabutylammonium hexafluorophosphate gave the paramagnetic clusters [Co₆(μ₃-S)₈(PEt₃)₆](Y) (Y = BPh₄, (1), PF₆, (2)). These compounds can be easily reduced by sodium napthalenide to the diamagnetic species [Co₆(μ₃-S)₈(PEt₃)₆] · 2C₄H₈O (3). The molecular structures of 1 and 3 have been established by single-crystal X-ray diffraction methods. Crystal data: (1) space group P , a = 19.481(9), b = 15.562(7), c = 12.390(b) Å, α = 92.70(8), β = 94.50(7), γ = 94.10(9)°, Z = 2, (3) space group R , a = 11.780(6) Å, α = 92.50(7)°, Z = 1. Both structures were solved by the heavy atom method and refined by full-matrix least-squares techniques to the conventional R factors values of 0.050 for 1 and 0.044 for 3 on the basis of 4251 and 1918 observed reflections, respectively. The two clusters [Co₆(μ₃-S)₈)(PEt₃)₆]^1+,0 are isostructural, the inner core consisting of an octahedron of cobalt atoms with all the faces symmetrically capped by triply bridging sulphur atoms. Each metal centre is additionally linked to a triethylphosphine group so that each cobalt atom is co-ordinated by four sulphur atoms and one phosphorus in a distorted square pyramidal environment. The addition of one electron whilst leaving unchanged the geometry of the inner framework, induces small changes in the structural parameters, the average Co---Co and Co---P distances being 2.794 (3) and 2.162 (2) Å for 1 and 2.817 (3) and 2.138 (2) Å for 3 respectively. Electrochemistry in non-aqueous solvents shows the electron-transfer sequence

Full-size image (3K)

The tricationic species is stable only in the short time of cyclic voltammetric tests.     

Unusual stabilization of cationic “M(η-allyl) (M = Pt, Pd) units by a dianionic cis-{Pt(C6F5)2(CCSiMe3)2} fragment

Chloride abstraction from [{M(η³ --- C₃H₅)Cl}_n] (M = Pt, n = 4 or M = Pd, n = 2) by (NBu₄)₂[cis-Pt(C₆F₅)₂(CCSiMe₃)₂] (1) gives rise to novel homo- and hetero-dinuclear zwitterionic derivatives (NBu₄) [{cis-Pt(C₆F₅)₂(CCSiMe₃)₂}M(η³-C₃H₅)] (M = Pt 2; M = Pd 3) which are formed by a M(η³-allyl)⁺ unit attached to both alkynyl ligands of the {cis-Pt(C₆F₅)₂(CCSiMe₃)₂}²⁻ fragment. The structure of 3 has been established by X-ray diffraction.     

Cis- and Trans-Coordination Assembly of Nitrogen Heterocycle with Copper（Ⅱ） and Silver（Ⅰ）

After the preparation of 1,4-bis（4,5-dihydro-lH-imidazol-2-yl）benzene（bdib）, a nitrogen heterocycle with potential coordination manners of both cis- and trans-configuration forms, three complexes, including cis-[Cuz（bdib ）2（/L-OCH3）2]Cl2·2MeOH（1）, trans-[Cu（bdib）（AcO）2]n（2）, and cis-[Ag2（bdib）2]（NO3）2.2H20（3）, were successfully self-assembled. Complexes 1 and 2 crystallized in the monoclinic system with P21/n space group and complex 3 in the triclinic system with P1 space group.     

Assembly of silver(I) coordination polymers incorporating pyromellitic acid and N-heterocyclic ligands

Five mixed ligands coordination polymers [Ag₄(apym)₂(pma)·(H₂O)₂]_n (1), {[Ag₄(dmapym)₄(pma)·(H₂O)₂]·(H₂O)₆}_n (2), [Ag₂(apyz)₂(H₂pma)·(H₂O)₄]_n (3), {[Ag₄(apyz)₂(pma)·(H₂O)₂]·(H₂O)₂}_n (4) and [Ag₄(NH₃)₈(pma)·(H₂O)₆]_n (5) (apym = 2-aminopyrimidine, dmapym = 4, 6-dimethyl-2-aminopyrimidine, apyz = 2-aminopyrazine, H₄pma = pyromellitic acid) were synthesized and characterized. For 1 and 2, as the substituents change from H to methyl, the dimensions of 1–2 decrease from three-dimension (3D) to one-dimension (1D) due to the steric effect of methyl groups. For 3 and 4, as the ratios of Ag₂O/apyz/pma vary from 1:1:1 to 2:1:1, the structure of 3 is a 1D ladder structure built from Ag-apyz double chains and pma anions, while the structure of 4 is a two-dimension (2D) grid. As excess ammonia is added to above four reaction systems, the structure of 5 contains unprecedented {[Ag(NH₃)₂]⁺}_n chains and pma anions. The substituent on the pyrimidyl ring, ratios of reactants, solvent systems and ligand isomers intensively influence the coordination environments of metal ion and the coordination modes of the carboxyl group, and thus determine the structures of the coordination polymers. The photoluminescent properties of 1–5 were also investigated.     

Hydrothermal Syntheses, Structures, and Properties of Two New Potassium Vanadium Phosphates: K3(VO) (V2O3) (PO4)2(HPO4) and K3 (VO) (HV2O3) (PO4)2(HPO4)

Two new potassium vanadium phosphates have been prepared and their structures have been determined from analysis of single crystal X-ray data. The two compounds, K₃(VO)(V₂O₃) (PO₄)₂(HPO₄) and K₃(VO)(HV₂O₃)(PO₄)₂(HPO₄), are isostructural, except for the incorporation of an extra hydrogen atom into the nearly identical frameworks. The structures consist of a three-dimensional network of [VO]_n chains connected through phosphate groups to a [V₂O₃] moiety. Magnetic susceptibility experiments indicate that in the case of the di-hydrogen compound, there are no significant magnetic interactions between the three independent vanadium (IV) centers. Crystal data: for K₃(VO)(V₂O₃)(PO₄)₂ (HPO₄), M_r = 620.02, orthorhombic space group Pnma (No. 62), a = 7.023(4) Å, b = 13.309(7) Å, c = 14.294(7) Å, V = 1336(2) ų, Z = 4, R = 5.02%, and R_w = 5.24% for 1238 observed reflections [I > 3σ(I)]; for K₃(VO)(HV₂O₃)(PO₄)₂(HPO₄), M_r = 621.04, orthorhombic space group Pnma (No. 62), a = 6.975(3) Å, b = 13.559(7) Å, c = 14.130(7) Å, V = 1336(1) ų, Z = 4, R = 6.02%, and R_w = 6.34% for 1465 observed reflections [I > 3σ(I)].     

A 3D porous indium(III) coordination polymer involving in-situ ligand synthesis

The hydrothermal reaction of In³⁺ and 1,2,4-benzenetricarboxylic acid with the presence of piperazine leads to the generation of a novel 3D porous coordination polymer, [H₃O][In₂(btc)(bdc)(OH)₂]·5.5H₂O (1), (btc=1,2,4-benzenetricarboxylate, bdc=1,4-benzenedicarboxylate). Compound 1 crystallizes in orthorhombic space group Pbca with a=16.216(7) Å, b=13.437(6) Å, c=31.277(14) Å, and Z=8. It is interesting to find that the in-situ decarboxylation reaction of 1,2,4-benzenetricarboxylate (btc) partially transformed into 1,4-benzenedicarboxylate (bdc) occurs. The 16 indium(III) centers were linked by four btc, four bdc and two μ₂-OH ligands to form a box-girder. The adjacent box-girders are further connected by the bdc and btc ligands to generate a novel porous metal–organic framework containing nanotubular open channel with a cross-section of approximately 11.5×11.3 Å². The micropores are occupied by lattice water molecules, and the solvent-accessible volume of the unit cell was estimated to be 3658.6 Å³, which is approximately 53.7% of the unit-cell volume (6815.4 Å³).     

Molecular structure of some [1.1 ]ferrocenylruthenocenophanium (n = 1,2 polyiodides salts

Oxidation of [1.1]ferrocenylruthenocenophane with a large excess and 1.5 equivalents of iodine gives dicationic iodo[1.1]ferrocenylruthenocenophanium²⁺I₃⁻ · 0.5I₂2 (1) and monocationic [1.1]ferrocenylruthenocenophanium⁺I₃⁻ (2) salts respectively. The structures of 1 and 2 were analyzed by single-crystal X-ray diffraction studies. The crystal form of 1 is monoclinic space group C2/c, A = 21.35](5), B = 20.594(5), C = 17.397(4) Å, β = 124.17(1)°, Z = 8, and the final R = 0.068 and R_w = 0.070. The cation formulated as [Fe^III(C₅H₄CH₂C₅H₄)₂Ru^IVI]²⁺ exists in a syn-conformation as in the cases of the neutral compound. The distance between the Ru^IV and Fe^II is 4.656(4) Å, which is much shorter than the value of the neutral compound (4.792(2) Å), and the bond angle of I---Ru^IV,Fe^III is 81.26°. The dihedral angle between the two η⁵-C₅H₄ (fulvenide) rings on the Ru^IV moiety is 37.56° due to the Ru^IV---I bond (2.758(3) Å). These two rings of Fe^III and Ru^IV moieties are essentially eclipsed. The unit cell has three kinds of I₃⁻ (I_3a⁻, I_3b⁻ and I_3c⁻) and one I₂, and the formula of 1 is given as [Fe^III(C₅H₄CH₂CSH₄)₂Ru^IVI]²⁺I₃⁻ · 0.5(I₃⁻)₂ · 0.5I₂. The crystal of 2 formulated as [Fe^III(C₅H₄CH₂C₅H₄)₂Ru^II]⁺I₃⁻ is triclinic space group

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, and the final R = 0.067 and R_w = 0.068. The unit cell has two independent molecules (unit A and B); i.e. two kinds of distance between the Ru^II and Fe^III, are observed; one (A) is 4.615(3) and the other (B) is 4.647(3) α. The two η⁵-C₅H₄ rings of both Fe^III and Ru^II are essentially staggered and the dihedral angles between the rings of FcH and RcH moieties are less than 5.8°. Typical ferrocenium-type broad singlet ⁵⁷Fe-Mössbauer lines are observed for both salts (1, 2) at all temperatures.