The Cluster Compounds Ag[W6Br14] and Ag2[W6Br14]

The reaction of W₆Br₁₂ with AgBr in evacuated silica tubes (temperature gradient 925 K/915 K) yielded brownish black octahedra of Ag[W₆Br₁₄] ( I ) and yellowish green platelets of Ag₂[W₆Br₁₄] ( II ) both in the low temperature zone. ( I ) crystallizes cubically (Pn3 (no. 201); a = 13.355 Å, Z = 4) and ( II ) monoclinically (P2₁/c (no. 14); a = 9.384 Å, b = 15.383 Å, c = 9.522 Å, β = 117.34°, Z = 2). Both crystal structures contain isolated cluster anions, namely [(W₆Brⁱ₈)Br^a₆]^1– and [(W₆Brⁱ₈)Br^a₆])]^2–, respectively, with the mean distances and angles: ( I ) d(W–W) = 2.648 Å, d(W–Brⁱ) = 2.617 Å, d(W–Br^a) = 2.575 Å, d(Brⁱ…Brⁱ) = 3.700 Å, d(Brⁱ…Br^a) = 3.692 Å, ∠W–Brⁱ–W = 60.78°. ( II ) d(W–W) = 2.633 Å, d(W–Brⁱ) = 2.624 Å, d(W–Br^a) = 2.613 Å, d(Brⁱ…Brⁱ) = 3.710 Å, d(Brⁱ…Br^a) = 3.707 Å, ∠W–Brⁱ–W = 60.23°. The Ag⁺ cations are trigonal antiprismatically coordinated in ( I ) with d(Ag–Br) = 2.855 Å, but distorted trigonally planar in ( II ) with d(Ag–Br) = 2.588–2.672 Å. The structural details of hitherto known compounds with [W₆Br₁₄] anions will be discussed.     

THE METASTABLE PARTIALLY POSITIVELY CHARGED Se6 MOLECULE: PREPARATION,CHARACTERISATION AND X-RAY CRYSTAL STRUCTURE OF [Ag2(Se6)(SO2)2][Sb(OTeF5)6]2, [Ag2Se6][AsF6]2 AND [AgSe6][Ag2(SbF6)3]

Reactions designed to give Se₆[Sb(OTeF₅)₆]₂ by the reaction of Se₂Br₂, 4Se, and 2Ag[Sb(OTeF₅)₆] lead to products that include [Ag₂(Se₆)(SO₂)₂][Sb(OTeF₅)₆]₂(1). The distorted cubic (Ag₂Se₆ ²⁺) _n consists of a Se₆ molecule bicapped by two silver cations (local D_3d sym.). Reactions of AgMX₆ (M = As, Sb) with selenium in liquid SO₂ yielded crystals of [Ag₂Se₆][AsF₆]₂ (2) and [AgSe₆][Ag₂(SbF₆)₃] (3). Both salts contain stacked arrays of [AgSe₆]⁺ half-sandwich cationic units. [Ag₂Se₆][AsF₆]₂ in addition contains stronger, linear Se─Ag─Se horizontal linkages between the vertically stacked cationic columns. [AgSe₆][Ag₂(SbF₆)₃] features a remarkable three-dimensional [Ag₂(SbF₆)₃]^? anion held together by strong Sb─F···Ag contacts between component Ag⁺ and SbF₆ ^? ions. Hexagonal channels through this honeycomb-like anion are filled by the stacked [AgSe₆ ⁺]_x.     

Syntheses,structures and properties of four second-sphere coordination complexes via metal halide anion and naphthalene-based ligand

Second-sphere coordination refers to any intermolecular interactions with the ligands directly bound to the primary coordination sphere of a metal ion. Four supramolecular complexes, 0.5[L·2H]²⁺·0.5[MCl₄]^2?·[CH₃OH]·0.5[CH₂Cl₂] (M = Co, crystal 1; M = Mn, crystal 2), 0.5[L·2H]²⁺·0.5[ZnBr₄]^2?·[CH₃OH]·0.5[CH₂Cl₂] (crystal 3), and 0.5[L·2H]²⁺·0.5[Cu₂Br₄]^2?·H₂O (crystal 4), based on naphthalene-based ligand N,N,N′,N′-tetra-p-methylnaphthyl-ethanediamine (L), have been synthesized. X-ray analysis reveals that 1–3 are isostructural, in which the methanol molecules are bridges, connecting the protonated L and metal chloride anions via N–H?O and O–H?Cl (Br) interactions to construct the host framework, and forming X-shaped cavity accessible for the inclusion of weakly polar guest molecules of dichloromethane. Dichloromethane is connected with the host framework through van der Waals forces. In 4, a dinuclear anion [Cu₂Br₄]^2? is connected with the ligand through N–H?Br interactions, in which the water molecules are accommodated between chains formed by the ligand and [Cu₂Br₄]^2?. Structure stability, thermal analysis, and photoluminescent properties were studied for 1–4.     

Syntheses and structures of Cd(II) and Co(II) compounds of 4-[(3-pyridyl)methylamino]benzoate anion

Three coordination polymers containing Cd(II) and Co(II), connected via 4-[(3-pyridyl)methylamino]benzoate (L^?), have been synthesized in hydrothermal conditions. In [Cd(L)Cl] _n (1), adjacent Cd(II) cations are linked by carboxylates to give a dinuclear cluster. Pairs of L^? bridge the dinuclear cluster to form double helical chains, and these chains are further linked by Cl^? to produce a 4-connected net with (4²?·?6³?·?8) topology. [CdL₂] _n (2) contains 1-D ladder-like chains. The packing structure displays a 3-D supramolecular structure, with π?···?π interactions stabilizing the framework. [CoL₂] _n (3) has a 2-D extended supramolecular structure via π?···?π interactions of 1-D coordination polymers of 3. The crystal structures of 1–3 have been determined by single-crystal X-ray diffraction. Luminescent properties for 1 and 2 are discussed.     

Synthesis and characterization of [Cu(Phca2en)(PPh3)X] (X=Cl, Br, I, NCS, N3) complexes: crystal structures of [Cu(Phca2en)(PPh3)Br] and [Cu(Phca2en)(PPh3)I]

New mixed-ligand copper(I) complexes, [Cu(Phca₂en)(PPh₃)X], [Phca₂en = N,N′-bis(β-phenylci-nnamaldehyde)-1,2-diiminoethane and X=Cl (1), Br (2), I (3), NCS (4), N₃ (5)] have been synthesized and characterized by various techniques. ¹H and ¹³C-NMR and IR spectral data of these copper(I) complexes are compared with the free ligand to elucidate some structural features. The structures of [Cu(Phca₂en)(PPh₃)Br] (2) and [Cu(Phca₂en)(PPh₃)I] (3) have been determined from single-crystal data showing that the coordination geometry around copper atom is a distorted tetrahedron. Furthermore, these Cu(I) complexes exhibit supramolecular motifs of the type multiple phenyl embraces resulting from attractive interactions between phenyl rings of PPh₃ moieties. The presence of the C–H…Cu weak intramolecular hydrogen bonds, due to the trapping of C–H bonds in the vicinity of the metal atoms, is also reported.     

Zur Strukturchemie der Alkyl- und Arylhalogenoarsenate(III), [Me2As2Cl5]–, [RAsCl3]–, [R2As2Br6]2– (R = Me,Et, Ph) und [Ph2AsX2]– (X = Cl,Br)

Structural Chemistry of the Alkyl- and Arylhaloarsenates(III) [Me₂As₂Cl₅]^–, [RAsCl₃]^–, [R₂As₂Br₆]^2– (R = Me, Et, Ph) and [Ph₂AsX₂]^– (X = Cl, Br) The alkyl- and arylhaloarsenates(III) [Ph₄P][Me₂As₂Cl₅] ( 1 ), [Ph₄P][RAsCl₃] (R = Me, Et, Ph, 2 – 4 ), [Me₃PhN][PhAsCl₃] ( 5 ), [Ph₄P]₂[R₂As₂Br₆] (R = Me, Et, Ph, 6 – 8 ), [n-Pr₄N][Ph₂AsCl₂] ( 9 ) and [n-Bu₄N][Ph₂AsBr₂] ( 10 ) have been prepared and their structures established by X-ray diffraction. In contrast to the chloroarsenates(III) 2 – 5 , which all contain isolated ψ-trigonal bipyramidal anions [RAsCl₃]^–, the analogous bromoarsenates(III) 6 – 8 exhibit dimeric structures. Whereas the trans sited As–Cl distances in 2 and 3 are very similar a pronounced degree of asymmetry is apparent for the Cl–As–Cl three-centre bonds in 4 and 5 [2.396(1) and 2.602(1) Å in 5]. In 6 and 7 C_i symmetry related RAsBr₂ units are connected through long As…Br bonds [2.926(1) and 3.116(2) Å in 6 ]. The bromophenylarsenate(III) anion of 8 which contains two effectively undistorted ψ-trigonal bipyramids [PhAsBr₃]^– associated by weak As…Br interactions [3.117(2) Å]. In view of its very long bridging As…Cl distances the [Me₂As₂Cl₅]^– anion in 1 can, as 6 an 7 , be regarded as two MeAsCl₂ molecules weakly linked through a chloride ion.     

Neue Kronenether‐stabilisierte Oxoniumhalogenochalkogenate: [H3O(Dibromo‐benzo‐18‐Krone‐6)]2[Se3Br10] und [H5O2(Bis‐dibromo‐dibenzo‐24‐Krone‐8]2[Se3Br8]

Novel Oxonium Halogenochalcogenates Stabilized by Crown Ethers: [H₃O(Dibromo‐benzo‐18‐crown‐6)]₂[Se₃Br₁₀] and [H₅O₂(Bis‐dibromo‐dibenzo‐24‐crown‐8]₂[Se₃Br₈] Two novel complex oxonium bromoselenates(II,IV) and –(II) are reported containing [H₃O]⁺ and [H₅O₂]⁺ cations coordinated by crown ether ligands. [H₃O(dibromo‐benzo‐18‐crown‐6)]₂[Se₃Br₁₀] ( 1 ) and [H₅O₂(bis‐dibromo‐dibenzo‐24‐crown‐8]₂[Se₃Br₈] ( 2 ) were prepared as dark red crystals from dichloromethane or acetonitrile solutions of selenium tetrabromide, the corresponding unsubstituted crown ethers, and aqueous hydrogen bromide. The products were characterized by their crystal structures and by vibrational spectra. 1 is triclinic, space group (Nr. 2) with a = 8.609(2) Å, b = 13.391(3) Å, c = 13.928(3) Å, α = 64.60(2)°, β = 76.18(2)°, γ = 87.78(2)°, V = 1404.7(5) ų, Z = 1. 2 is also triclinic, space group with a = 10.499(2) Å, b = 13.033(3) Å, c = 14.756(3) Å, α = 113.77(3)°, β = 98.17(3)°, γ = 93.55(3)°. V = 1813.2(7) ų, Z = 1. In the reaction mixture complex redox reactions take place, resulting in (partial) reduction of selenium and bromination of the crown ether molecules. In 1 the centrosymmetric trinuclear [Se₃Br₁₀]^2? consists of a central Se^IVBr₆ octahedron sharing trans edges with two square planar Se^IIBr₄ groups. The novel [Se₃Br₈]^2? in 2 is composed of three planar trans‐edge sharing Se^IIBr₄ squares in a linear arrangement. The internal structure of the oxonium‐crown ether complexes is largely determined by the steric restrictions imposed by the aromatic rings in the crown ether molecules, as compared to complexes with more flexible unsubstituted crown ether ligands.     

Coordination of Alkaline Earth Metal Ions in the Inverted Cucurbit[7]uril Supramolecular Assemblies Formed in the Presence of [ZnCl4]2− and [CdCl4]2−

A convenient method to isolate inverted cucurbit[7]uril (iQ[7]) from a mixture of water‐soluble Q[n]s was established by eluting the soluble mixture of Q[n]s on a Dowex (H⁺ form) column so that iQ[7] could be selected as a ligand for coordination and supramolecular assembly with alkaline earth cations (AE²⁺) in aqueous HCl solutions in the presence of [ZnCl₄]^2? and [CdCl₄]^2? anions as structure‐directing agents. Single‐crystal X‐ray diffraction analysis revealed that both iQ[7]–AE²⁺–[ZnCl₄]^2?–HCl and iQ[7]–AE²⁺–[CdCl₄]^2?–HCl interaction systems yielded supramolecular assemblies, in which the [ZnCl₄]^2? and [CdCl₄]^2? anions presented a honeycomb effect, and this resulted in the formation of linear iQ[7]/AE²⁺ coordination polymers through outer‐surface interactions of Q[n]s.     

A two‐dimensional network formed by self‐associating silver(I) perchlorate with 3‐[4‐(2‐thienyl)‐2H‐cyclopenta[d]pyridazin‐1‐yl]benzonitrile

In the organometallic silver(I) supramolecular complex poly[[silver(I)‐μ₃‐3‐[4‐(2‐thienyl)‐2H‐cyclopenta[d]pyridazin‐1‐yl]benzonitrile] perchlorate methanol solvate], {[Ag(C₁₈H₁₁N₃S)](ClO₄)·CH₃OH}_n, there is only one type of Ag^I center, which lies in an {AgN₂Sπ} coordination environment. Two unsymmetric multidentate 3‐[4‐(2‐thienyl)‐2H‐cyclopenta[d]pyridazin‐1‐yl]benzonitrile (L) ligands link two Ag^I atoms through π–Ag^I interactions into an organometallic box‐like unit, from which two 3‐cyanobenzoyl arms stretch out in opposite directions and bind two Ag^I atoms from neighboring box‐like building blocks. This results in a novel two‐dimensional network extending in the crystallographic bc plane. These two‐dimensional sheets stack together along the crystallographic a axis to generate parallelogram‐like channels. The methanol solvent molecules and the perchlorate counter‐ions are located in the channels, where they are fixed by intermolecular hydrogen‐bonding interactions. This architecture may provide opportunities for host–guest chemistry, such as guest molecule loss and absorption or ion exchange. The new fulvene‐type multidentate ligand L is a good candidate for the preparation of Cp–Ag^I‐containing (Cp is cyclopentadienyl) organometallic coordination polymers or supramolecular complexes.     

Syntheses,structural characteristics,and antimicrobial activities of new organotin(IV) 3-(4-bromophenyl)-2-ethylacrylates

New organotin(IV) carboxylates, [n-Bu₂SnL₂] (1), [Et₂SnL₂] (2), [Me₂SnL₂] (3), [n-Oct₂SnL₂] (4), [n-Bu₃SnL] _n (5), [Me₃SnL] _n (6), and [Ph₃SnL] _n (7), where L?=?3-(4-bromophenyl)-2-ethylacrylate, were synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn). Spectroscopic studies confirm coordination of L to the organotin moiety via COO group. Single-crystal X-ray analysis reveals bridging mode of coordination in 6. Packing diagram established a supramolecular cage-like structure for 6 due to Sn–O interactions (3.287?Å). Subsequent antimicrobial activities proved them to be active biologically.     

The outer-sphere association of p-sulfonatothiacalix[4]arene with some Co(III) complexes: the effect on their redox activity in aqueous solutions

The effect of the ion-pairing of Co(III) complexes with p-sulfonatothiacalix[4]arene (STCA) on Fe(II)–Co(III) electron transfer rate was evaluated from the analysis and comparison of kinetic data in double Co(III)–Fe(II) and triple Co(III)–Fe(II)—STCA systems at various concentration conditions. Complexes [Co(en)₃]³⁺(1), [Co(en)₂ox]⁺(2), [Co(dipy)₃]³⁺ (3), [Co(His)₂]⁺(4) and [Fe(CN)₆]⁴⁻ were chosen as Co(III) and Fe(II) compounds. The effect of STCA was found to correlate with the association mode. The outer-sphere association with STCA was found to exhibit the insignificant effect on Fe(II)–Co(III) electron transfer k _et constants for complexes 3 and 4 with bulky and rigid chelate rings, while more sufficient inclusion of flexible ethylendiaminate rings of 1 and 2 into the cavity of STCA results in the unusual increase of k _et.     

Different conjugated system Cd(II)/Hg(II) Schiff base complexes: syntheses,supramolecular metal−organic frameworks,luminescent properties and DFT study

A series of different conjugated systems of 2D/3D supramolecular metal-organic frameworks (SMOFs) are constructed by C/O?H?Cl hydrogen bonds and π?π interactions. These complexes, [HgL¹Cl₂] (1), [HgL²Cl₂] (2), [HgL³Cl₂] (3), [CdL⁴Cl₄]₂ (4), and [CdL⁵Cl₂(CH₃OH)] (5), have been synthesized and characterized by single-crystal X–ray diffraction, ¹H NMR, FT–IR, and EA. The X-ray diffraction analyses reveal that 1 features a 3D supramolecular framework with {4⁴·6⁶} topology structure, while 2, 3, and 5 exhibit 3D 6-connected {4¹²·6³} topology structures. Complex 4 shows a two-dimensional layer with 4⁴ topology structure. Based on these varied structures caused by different conjugated system, the emission maximum wavelengths of 1–5 can be tuned in a large range of 492–587 nm. Both electron-donating ability and the conjugated system in general can support λ_em shift to red direction. In order to have better understanding of electronic transitions of the complexes, a time-dependent DFT study has been performed. The enhancement of the fluorescence intensities for the complexes compared to the ligands indicates potential to serve as photoactive materials.     

Structures and luminescent properties of four compounds based on binuclear metal-terpyridine building blocks

Four new coordination polymers, [Cd(3-TPTP)Cl]₂ (3-HTPTP = 4′-(3-tetrazolylphenyl)2,2′:6′2′′-terpyridine, 1), {[Cd(3-TPTP)(pBDC)_0.5]?4H₂O}_n (pH₂BDC = 1,4-benzenedicarboxylic acid, 2), {[Mn(3-TPTP)(mBDC)_0.5]?5H₂O}_n (mH₂BDC = 1,3-benzenedicarboxylic acid, 3), and [Pb(3-TPTP)(H₂O)₂]?OH (4), were obtained. Compounds 1–3 are composed of binuclear [M₂(3-TPTP)₂] ring as building unit. In 1, the binuclear rings pack into a 3-D supramolecular framework via various hydrogen bonds. In 2 and 3, the binuclear rings are connected by mBDC^2? and pBDC^2?, respectively, resulting in two types of 1-D chains. In 4, the mononuclear [Pb(3-TPTP)] units are connected by Pb?N weak interactions, giving a chiral 1-D coordination chain, which is further connected by O–H?N interaction to form a chiral 3-D supramolecular framework. The phase purity of 1–4 and luminescence properties of 1, 2, and 4 were also investigated.     

Synthesis and metal complexation studies of [2n]thiacalix[m]arene[m]pyrazine

Novel [2_n]thiacalixarenepyrazine and [2_n]thiacalixarenetriazine systems were synthesised by one-pot S_NAr reactions. A screening of the metal-complexing ability of [2₆]hexathiacalix[3]arene[3]pyrazine revealed its affinity for Cu^I, Cu^II and Ag^I metal salts.     

Die Kristallstrukturen von [Et3PNAsPh3]2[Ag2Br4] und [Et3PNAsPh3]2[Pd2Br6]

Crystal Structures of [Et₃PNAsPh₃]₂[Ag₂Br₄] and [Et₃PNAsPh₃]₂[Pd₂Br₆] Colourless single crystals of [Et₃PNAsPh₃]₂[Ag₂Br₄]( 1 ) and red single crystals of [Et₃PNAsPh₃]₂[Pd₂Br₆]( 2 ) have been isolated from saturated solutions in acetonitrile of equivalent mixtures of [Et₃PNAsPh₃]Br with AgBr and PdBr₂, respectively. Both complexes were characterized by IR spectroscopy and by crystal structure determinations. 1 : Space group P1¯, Z = 1, lattice dimensions at ‐70°C: a = 985.0(2), b = 1042.2(5), c = 1345.8(5) pm, α = 102.88(2)°, β = 105.73(2)°, γ = 94.94(2)°, R₁ = 0.0577. 2 : Space group P2₁/c, Z = 2, lattice dimension at ‐70°C: a = 1003.0(1), b = 1371.8(2), c = 1974.0(1) pm, β = 93.30(1)°, R₁ = 0.0458. The dimeric anions of 1 and 2 form planar, centrosymmetric complex units.     

Structural and Spectroscopic Studies of Halocuprate(I) and Haloargentate(I) Complexes [M2XnX′4−n]2−

The complexes [Cu₂Br₄]^2?, [Cu₂I₄]^2?, [Cu₂I₂Br₂]^2?, [Cu₂I₃Cl]^2?, [Ag₂Cl₄]^2? have been characterized as their isomorphous bis(triphenylphosphoranylidene)ammonium ([Ph₃PNPPh₃]⁺ = PNP⁺) salts by single crystal structural determinations. All anions show the centrosymmetric doubly halogen‐bridged forms [XM(μ‐X)₂MX]^2? with three‐coordinate metal atoms that have been observed in [M₂X₄]^2? complexes with other large organic cations. In [Cu₂I₂Br₂]^2? the iodide ligands occupy the bridging positions and the bromide the terminal positions, while in [Cu₂I₃Cl]^2?, obtained in an attempt to prepare [Cu₂I₂Cl₂]^2?, two of the iodide ligands occupy the bridging positions with the third iodide and the chloride ligand occupying two statistically disordered terminal positions. In [Ag₂Cl₄]^2? the distortion from ideal trigonal coordination of the metal atom is greater than in the copper complexes, but less than in other previously reported [Ag₂Cl₄]^2? complexes with organic cations. The ν(MX) bands have been assigned in the far‐IR spectra, and confirm previous observations regarding the unexpectedly simple IR spectra of [Cu₂X₄]^2? complexes.     

The 3[ndσ*(n+1)pσ] Emissions of Linear Silver(I) and Gold(I) Chains with Bridging Phosphine Ligands

The complexes [Au₃(dcmp)₂][X]₃ {dcmp=bis(dicyclohexylphosphinomethyl)cyclohexylphosphine; X=Cl^? ( 1 ), ClO₄^? ( 2 ), OTf^? ( 3 ), PF₆^? ( 4 ), SCN^?( 5 )}, [Ag₃(dcmp)₂][ClO₄]₃ ( 6 ), and [Ag₃(dcmp)₂Cl₂][ClO₄] ( 7 ) were prepared and their structures were determined by X‐ray crystallography. Complexes 2 – 4 display a high‐energy emission band with λ_max at 442–452 nm, whereas 1 and 5 display a low‐energy emission with λ_max at 558–634 nm in both solid state and in dichloromethane at 298 K. The former is assigned to the ³[5dσ*6pσ] excited state of [Au₃(dcmp)₂]³⁺, whereas the latter is attributed to an exciplex formed between the ³[5dσ*6pσ] excited state of [Au₃(dcmp)₂]³⁺ and the counterions. In solid state, complex [Ag₃(dcmp)₂][ClO₄]₃ ( 6 ) displays an intense emission band at 375 nm with a Stokes shift of ≈7200 cm^?1 from the ¹[4dσ*→5pσ] absorption band at 295 nm. The 375 nm emission band is assigned to the emission directly from the ³[4dσ^*5pσ] excited state of 6 . Density functional theory (DFT) calculations revealed that the absorption and emission energies are inversely proportional to the number of metal ions (n) in polynuclear Au^I and Ag^I linear chain complexes without close metal???anion contacts. The emission energies are extrapolated to be 715 and 446 nm for the infinite linear Au^I and Ag^I chains, respectively, at metal???metal distances of about 2.93–3.02 Å. A QM/MM calculation on the model [Au₃(dcmp)₂Cl₂]⁺ system, with Au???Cl contacts of 2.90–3.10 Å, gave optimized Au???Au distances of 2.99–3.11 Å in its lowest triplet excited state and the emission energies were calculated to be at approximately 600–690 nm, which are assigned to a three‐coordinate Au^I site with its spectroscopic properties affected by Au^I???Au^I interactions.     

The Mixed Valence Tungsten(IV,V) Compound Na[W2O2Br6]

The reaction of W₆Br₁₂, NaBr, and WO₂Br₂ in the presence of Br₂ in a sealed silica tube yields Na[W₂O₂Br₆] together with WOBr₄ and WO₂Br₂ in the low temperature zone (temperature gradient 1030/870 K). Na[W₂O₂Br₆] crystallizes orthorhombically in the space group Immm (no. 71) with a = 3.775 Å, b = 10.400 Å, c = 13.005 Å and Z = 2. Pairs of condensed trans-[WO₂Br₄] octahedra with a common Br₂ edge form along [100] double chains [W₂O_4/2Br₆]^1– via the oxygen atoms. The mixed valent tungsten atoms are bonded to W₂ pairs with a 2 c–3 e bond (d(W–W) = 2.946 Å, d(W–O) = 1.888 Å, d(W–Br^b) = 2.537 Å, d(W–Br^t) = 2.535 Å, ∢O–W–O = 177.4°, ∢Br^b–W–Br^b (endocyclic) = 109.0°). The Na⁺ cations connect the anionic double chains to form two-dimensional layers parallel (001), which interact by van der Waals forces. The cations are eightfold coordinated by a cube of the terminal Br^t ligands of the polymeric anions (d(Na–Br) = 3.138 Å). Na[W₂O₂Br₆] may be discussed as an intercalation compound of the oxide bromide WOBr₃.     

Bi24Ru3Br20: Ein pseudo-tetragonales Subbromid mit [RuBi6Br12]-Clustern und [Ru2Bi17Br4]-Gruppen

Bi₂₄Ru₃Br₂₀: A Pseudo-Tetragonal Structure with [RuBi₆Br₁₂] Clusters and [Ru₂Bi₁₇Br₄] Groups The melting reaction of Ru with Bi and BiBr yields black, lustrous, air insensitive crystals of the subbromide Bi₂₄Ru₃Br₂₀. The orthorhombic crystal structure (space group Pc2₁n, a = b = 1377.8(1) pm, c = 3222.3(4) pm, V = 6117.0 · 10⁶ pm³) deceives pseudo-symmetry with respect to the tetragonal space group P4/ncc leading to multiply twinned crystals. The structure can formally be subdivided in [RuBi₆Br₁₂] clusters, [Ru₂Bi₁₇Br₄] stacks, and [BiBr₄] groups.     

Synthesis and Complexation of 1,2-Bis[(monoaza[15]crown-5)-N-yl]glyoxime. Crystal Structure of (1,2-Bis[(monoaza[15]crown-5)-N-yl]glyoximato)palladium(II)

A new vicinal dioxime ligand with two crown-ether groups, 1,2-bis[(monoaza[15]crown-5)-N-Yl]-glyoxime(LH₂), has been prepared from cyanogen di-N-oxide and monoaza[15]crown-5. Ni(II), Pd(II), and Pt(IV) complexes of LH₂ with or without alkali-metal ions bound to macrocyclic groups have been isolated. The high affinity of [Pd(LH)₂] and [Ni(LH)₂] for the K⁺ ion is observed in solvent extraction experiments. A single-crystal X-ray structure confirms the postulated geometry of [Pd(LH)₂]- The Pd-atom of the centro-symmetric molecule has square-planar PdN₄ coordination where Pd–N distances range from 1.978(3) to 1.970(3) Å. The N–Pd–N intraligand angle is 79.9(1)^°.