[1‐Allylpyridinium][Cu2Cl3]: Synthesis,X‐ray Structure and the Regularity of Crystal Architecture of 1‐Allyl/(amino)‐pyridinium Copper(I) Chloride π‐Complexes

By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C₅H₅N(C₃H₅)][Cu₂Cl₃] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) ų (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu₄Cl₆^2—)_n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu₂Cl₃] ( 2 ), [L₂Cu₂Cl₄] ( 3 ), and [LCuCl₂] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle.     

Changes in the conformational parameters of 1-allylbenzotriazole in a mixed halide π-complex [CuCl0.85Br0.15(C6H4N3CH2=CH2)] under the action of bromine atoms

Single crystals of [CuCl_0.85Br_0.15(C₆H₄N₃CH₂=CH₂)] (I) were obtained by alternating current electrochemical synthesis; their X-ray structural investigation has been carried out (DARCh automatic diffractometer, MoK _α radiation, θ/2θ scanning; 1460 reflections with F ≥ 4σ(F), R = 0.0517). The crystals are monoclinic, their space group is P2₁/c, a = 7.292(3) Å, b = 17.947(8) Å, c = 7.398(4) Å, β = 93.56(4)°, V = 966(1) ų, Z = 4). Complex I is close in structure to the previously investigated compound [CuCl(C₆H₄N₃CH₂=CH₂)] (II). In both structures, the trigonal-pyramidal surroundings of the copper atom include two halide atoms (one is apical), a nitrogen atom, and a C=C group. The Cu₂X₂ dimers are associated into {[Cu₂X₂(C₆H₅N₃CH₂=CH₂)]}_n layers due to the bridging function of the 1-allylbenzotriazole molecule. In spite of the similar coordination polyhedra of the metal atoms and identical bridging function of the ligand molecule in I and II, the differences in the conformation parameters of the allyl group π-coordinated by the copper(I) atom (trans-like in I and cis-like in II) caused by the presence of bromine atoms in the coordination sphere predetermine different structures of the organometallic [Cu₂X₂(C₆H₅N₃CH₂=CH₂)]₄ tetramer subunits in the layers and, as a consequence, formation of different crystal structures. Original Russian Text Copyright ? 2005 by E. A. Goreshnik, B. M. Mykhalichko, and V. N. Davydov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 1, pp. 174–178, January–February, 2005.     

Magnetic Properties of the cis-[CuCl2(DMSO)2] Complex

Theoretical and Experimental Chemistry - The magnetochemical behavior of the cis-[CuCl2(DMSO)2] complex was analyzed. cis-Complex crystals were found to be perfectly paramagnetic above 50 K and...     

Crystal Structures of Hydrazinium(II) Salts of [SbF6]– and [Sb2F11]–

N₂H₆(Sb₂F₁₁)₂ was synthesized by the reaction of N₂H₆F₂ with excess of SbF₅ in anhydrous hydrogen fluoride (aHF). It crystallizes in the triclinic space group P$\bar{1}$ (No. 2) with a = 6.6467(3) Å, b = 8.3039(4) Å, c = 8.3600(5) Å, α = 76.394(5) ^o, β = 70.161(5) ^o, γ = 70.797(5) ^o, V = 405.90(4) ų at 150 K, Z = 2. When it is redissolved in aHF, it solvolysis with the release of SbF₅ yielding N₂H₆(SbF₆)₂ which crystallizes in the monoclinic C2/c space group (No. 15) with a = 7.3805(3) Å, b = 12.3248(5) Å, c = 10.4992(4) Å, β = 92.218(4) ^o, V = 954.33(7) ų at 150 K, and Z = 8. No other phases were observed in crystallization products when different molar ratios of N₂H₆F₂/SbF₅ (1:1,2:3,1:3) in aHF were used as starting materials.     

Crystal structure of a new π-complex of AgClO4 with 1-allyl-5-(2-pyridyl)-1H-tetrazole of the composition [Ag2(C9H6N5)2](ClO4)2

By the AgClO₄ interaction with 1-allyl-5-(2-Pyridyl)-1H-tetrazolee (1aPyt) in a methanol solution, an [Ag₂(1aPyt)₂](ClO₄)₂ π-complex is obtained, which is studied using single crystal X-ray diffraction.     

Copper(I) halide complexes with N,N′-diallyl-N,N,N′,N′-tetramethylethylenediaminium (L2+). Synthesis and crystal structures of the complexes [L0.5CuCl2], [L0.5CuCl0.72Br1.28], and [L0.5CuBr2]

The Eschweiler-Clarke reaction of ethylenediamine with formaldehyde and formic acid yielded N,N,N′,N′-tetramethylethylenediamine, which was alkylated with allyl chloride or allyl bromide to give the corresponding N,N′-diallyl-N,N,N′,N′-tetramethylethylenediaminium (L²⁺) dihalides. In methanolic solutions of copper(II) halide and an appropriate ligand, ac electrochemical synthesis with copper wire electrodes afforded single crystals of Cu(I) complexes with L²⁺: [L_0.5CuCl₂] (I), [L_0.5CuCl_0.72Br_1.28] (II), and [L_0.5CuBr₂] (III). The crystal structures of complexes I–III were determined by X-ray diffraction study. The isostructural crystals of I and II are monoclinic, space group P2₁/n, Z = 4. For I: a = 7.632(4) Å, b = 11.318(5) Å, c = 10.635(5) Å, β = 98.551(7)°, V = 908.4(7) ų. For II: a = 7.7415(7) Å, b = 11.4652(9) Å, c = 10.7267(10) Å, β = 98.351(4)°, V = 942.0(2) ų. The organic cation L²⁺ acts as a bridge linking a pair of separate cuprous halide fragments Cu₂X₄. Although being isostoichiometric with I and II, complex III has a different structure. The crystals of III are monoclinic, space group P2₁/c, a = 6.519(2) Å, b = 9.060(3) Å, c = 16.284(6) Å, β = 97.219(4)°, V = 954.2(6) ų, Z = 4. In structure III, the inorganic fragment forms infinite polymer chains (CuBr ₂ ^? ) _n . The organic and inorganic parts are held together only by electrostatic interactions. Structures I–III are stabilized by hydrogen bonds (C)H…X (2.6–2.9 Å).     

Synthesis, Raman spectra and crystal structures of [Cu(XeF2)n](SbF6)2 (n=2, 4)

Pure [Cu(XeF2)2](SbF6)2 was prepared by the reaction of Cu(SbF 6) 2 with a stoichiometric amount of XeF2 in anhydrous hydrogen fluoride (aHF) at ambient temperature. The reaction between Cu(SbF6)2 and XeF2 (1:4 molar ratio) in aHF yielded [Cu(XeF2)4](SbF6)2 contaminated with traces of Xe 2F 3SbF6 and CuF2. The 6-fold coordination of Cu(2+) in [Cu(XeF2)2](SbF6)2 includes two fluorine atoms from two XeF2 ligands and four fluorine atoms provided by four [SbF6](-) anions. The neighboring [Cu(XeF 2)2](2+) moieties are connected via two [SbF6] units, with the bridging fluorine atoms in cis positions, into infinite [Cu(eta(1)-XeF2)2](cis-eta(2)-SbF 6)2[Cu(eta(1)-XeF 2)2] chains. Because of the high electron affinity of Cu(2+), coordinated XeF2 shows the highest distortion (Xe-Fb=210.2(5) pm, Xe-Ft=190.6(5) pm) observed so far among all known [M(x+)(XeF2)n](A)x (A=BF4, PF6, etc.) complexes. The four equatorial coordination sites of the Cu(2+) ion in [Cu(XeF 2) 4](SbF6)2 are occupied by four XeF 2 ligands. Two fluorine atoms belonging to two [SbF6] units complete the Cu (2+) coordination environment. The neighboring [Cu(XeF2)4](2+) species are linked via one [SbF6] unit, with bridging fluorine atoms in trans positions, into linear infinite [Cu(eta(1)-XeF2)4](trans-eta(2)-SbF6)[Cu(eta(1)-XeF2)4] chains. To compensate for the remaining positive charge, crystallographically independent [SbF6](-) anions are located between the chains and are fixed in the crystal space by weak Xe...F(Sb) interactions.     

Crystal Growth and Crystal Structures of Gold(V) Compounds: Cu(AuF6)2, Ag(AuF6)2, and O2(CuF)3(AuF6)4 ⋅ HF

Crystal growth from anhydrous hydrogen fluoride solutions of M²⁺ (M=Cu, Ag) and [AuF₆]⁻ gave M(AuF₆)₂ salts (M=Cu, Ag). Similar attempts to prepare single crystals of the corresponding nickel, zinc and magnesium salts failed. The crystal structure of Cu(AuF₆)₂ consists of layers of Cu²⁺ cations connected by [AuF₆]⁻ anions, thus forming slabs. Only van der Waals interactions exist between adjacent slabs. The crystal structure of Ag(AuF₆)₂ consists of a three-dimensional framework in which Ag⁺ cations are linked by [AuF₆]⁻ anions. Both structures are members of the M^II(X^VF₆)₂ family, in which seven different structure types have been observed to date. In the crystal structure of O₂(CuF)₃(AuF₆)₄ ⋅ HF, the bridging AuF₆ units connect [−Cu−F−Cu−F−]_∞ chains to form stacks between which O₂⁺ cations and HF molecules are located.     

X–ray Single Crystal Structure and Raman Spectrum of Ammonium Hexafluoroarsenate

The structure of ammonium hexafluoroarsenate, NH₄AsF₆, has been determined by X‐ray diffraction using a single crystal grown from saturated solution in anhydrous HF. NH₄AsF₆ crystallizes rhombohedral with the KOsF₆ structure type, with a = 7.459(3) Å, c = 7.543(3) Å (at 200 K), Z = 3, space group (No. 148). No phase transition was observed in the 100 K–296 K temperature range. The structure is dominated by regular AsF₆ octahedra and disordered NH₄⁺ cations. Raman spectrum of a single crystal of NH₄AsF₆ shows the bands at 372 cm^?1, 572 cm^?1, 687 cm^?1 (AsF₆^?) and at 3240 cm^?1 and 3360 cm^?1 (NH₄⁺).     

Environment‐Adopting Surfaces with Reversibly Switchable Morphology

Two‐component polymer brushes (polystyrene and poly(2‐vinylpyridine)) were synthesized by grafting from the surface of Si‐wafers. The brushes are sensitive to the surrounding medium, and their morphology and composition of the top of a brush can be switched upon exposure to different solvents. Thus surface energetic states and roughness of the film can be precisely tuned.