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.     

Anion intercalation and exchange in Al(OH)3-derived compounds

Precipitation of Al³⁺ at pH = 10 in excess Li₂CO₃ leads to an anion exchanging compound, [Al₂Li(OH)₆]⁺₂CO²⁻₃. This compound exhibits, compared to [Mg₃Al(OH)₈]⁺₂CO²⁻₃, a higher degree of size selectivity in anion exchange. The structure of the [Al₂Li(OH)₆]⁺ layers is gibbsite-like, with a (110) diffraction feature at d = 4.35 Å indicating a pronounced Al³⁺ ordering. As claimed originally by Serna et al., the structure is [Al₂Li(OH)₆]⁺A^z−_1/z rather than [Al₂(OH)₆]Li⁺A^z−_1/z, with the Li⁺ coordinated in the octahedral positions left vacant by Al³⁺. This emerges from the details of a lithium-leaching process, which proposedly leads to a novel compound, [Al₂H(OH)₆]⁺A^z−_1/z.     

Metal-betaine interactions—X. Preparation and crystal structures of bis(triethyl betaine)bis(nitrato)disilver(I) and catena-bis(triethyl betaine)disilver(I) diperchlorate

Two silver(I) complexes of triethyl betaine (Et₃N⁺CH₂COO⁻, Et₃BET) have been prepared and characterized by X-ray crystallography. Both complexes, [Ag₂(Et₃BET)₂ (NO₃)₂] (1) and [Ag₂(Et₃BET)₂]_n (ClO₄)_2n (2), contain centrosymmetric bis-carboxylato-bridged Ag₂(carboxylato-O,O′)₂ dimers (Ag---O = 2.16–2.23 Å). The dimeric unit in 1 is bound to a chelating nitrato group [Ag---O = 2.524(3), 2.619(3) Å] at each axial site, resulting in a discrete molecule. In 2 the dimers are extended into a stair-like cationic chain via the coordination of each metal centre by a carboxylato oxygen atom [Ag---O =2.565(5) Å] from an adjacent unit. The intra-dimer Ag… Ag distance is 2.928(1) Å for 1 and 2.856(2) Å for 2.     

[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.     

Synthesis and conformational studies of palladium(II) complexes containing [PhP(O)NP(E)Ph]− (E=S or Se)

The ligands [Ph₂P(O)NP(E)Ph₂]⁻ (E=S I; E=Se II) can readily be complexed to a range of palladium(II) starting materials affording new six-membered Pd–O–P–N–P–E palladacycles. Hence ligand substitution reaction of the chloride complexes [PdCl₂(bipy)] (bipy=2,2′-bipyridine), [{Pd(μ-Cl)(L–L)}₂] (HL–L=C₉H₁₃N or C₁₂H₁₃N), [{Pd(μ-Cl)Cl(PMe₂Ph)}₂] or [PdCl₂(PR₃)₂] [PR₃=PPh₃; 2PR₃=Ph₂PCH₂CH₂PPh₂or cis-Ph₂PCH=CHPPh₂] with either I (or II) in thf or CH₃OH gave [Pd{Ph₂P(O)NP(E)Ph₂-O,E}(bipy)]PF₆, [Pd{Ph₂P(O)NP(E)Ph₂-O,E}(L–L)], [Pd{Ph₂P(O)NP(E)Ph₂-O,E}Cl(PMe₂Ph)] or [Pd{Ph₂P(O)NP(E)Ph₂-O,E} (PR₃)₂]PF₆ in good yields. All compounds described have been characterised by a combination of multinuclear NMR [31 P{1 H} and 1 H] and IR spectroscopy and microanalysis. The molecular structures of five complexes containing the selenium ligand II have been determined by single-crystal X-ray crystallography. Three different ring conformations were observed, a pseudo-butterfly, hinge and in the case of all three PR₃ complexes, pseudo-boat conformations. Within the Pd–O–P–N–P–Se rings there is evidence for π-electron delocalisation.     

Syntheses and structures of diorgano(halo- orpseudohalo-)(1,3-dithiole-2-thione-4,5-dithiolato)-stannates (1-), [Q][RSnX(dmit)] (Q=onium cation; X=halide orpseudohalide)

Ionic compounds, [Q] [R₂SnX(dmit)][dmit=1,3-dithiole-2-thione-dithiolate; Q=1,4-dimethylpyridinium or tetraalkylammonium; R=Phor alkyl; X=Cl, Br, I, NCS, NCSe, or N₃] have been obtained by (a) from R₂SnX₂ and [Q]₂[Zn(dmit)₂] in the presence of excess QX,(b) from halide exchange reactions in acetone solution between [Q] [R₂SnCl(dmit)]and a halide or pseudohalide source, or (c) by addition of QX to [R₂Sn(dmit)]. Crystalstructure determinations of [NEt₄] [Ph₂SnI(dmit)] and [1,4-Me₂pyridiniuml [Ph₂SnBr(dmit)] as well as of the mixed halides, [1a, 1b, 4a, 2] [Ph₂SnCl_nI₁₋n(dmit)] (n=0.57, 0.42 or0.22), indicated that the tin atoms have distorted trigonal bipyramidal geometries in the anions,with the X ligand and a dithiolato atom in the axial sites. The [R₂SnX(dmit)]⁻ anions remain essentially intact in organic solvents, but lose X⁻ on extractionwith H₂O to give the neutral species, R₂Sn(dmit).     

Hydrothermal Synthesis and Crystal Structure of [(CH3NH3)1.03K2.97]Sb12S20·1.34H2O

A novel thioantimonate(III) [(CH₃NH₃)_1.03K_2.97]Sb₁₂S₂₀·1.34H₂O was synthesized hydrothermally. It crystallizes in space groupP , witha=11.9939(7) Å,b=12.8790(8) Å,c=14.9695(9) Å,α=100.033(1)°,β=99.691(1)°,γ=108.582(1)°,V=2095.3(2) ų, andZ=2. The structure is determined from single crystal X-ray diffraction data collected at room temperature and refined toR(F)=0.037. In the crystal structure, each Sb(III) atoms has short bonds (2.37–2.58 Å) to three S atoms. The pyramidal [SbS₃] groups share common S atoms forming two types of centrosymmetric [Sb₁₂S₂₀] rings with the same topology. These rings are interconnected by weaker Sb–S bonds (2.92–3.29 Å) into 2-dimensional layers. Adjacent layers are parallel with K⁺and CH₃NH⁺₃ions and H₂O molecules located between them. Variation of bond valence sums calculated for the Sb(III) cations is found to be correlated with the coordination geometry. This is interpreted as due to the stereochemical activity of their lone electron pairs.     

Novel Antimony Complexes: [Ph4Sb]4 +[Sb4I16]4− · 2Me2C=O and [Ph4Sb]3 +[Sb5I18]3−

The [Ph₄Sb]₄ ⁺[Sb₄I₁₆]^4– · 2Me₂C=O and [Ph₄Sb]₃ ⁺[Sb₅I₁₈]^3– complexes were synthesized by reacting tetraphenylstibonium salts Ph₄SbX (X = I, OSO₂C₆H₄Me-4) with antimony triiodide in acetone. According to X-ray diffraction data, their tetra- and pentanuclear anions [Sb₄I₁₆]^4– and [Sb₅I₁₈]^3– have cyclic and linear structure, respectively.     

New tantalum polychalcogenides with infinite anionic chains: K12Ta6Se35 and KTaTe3

The new compounds K₁₂Ta₆Se₃₅ and KTaTe₃ have been synthesized through the reaction of Ta metal with a K₂Q_n(Q = Se, Te) flux. K₁₂Ta₆Se₃₅, crystallizes with 4 formula units in space group Pbcn of the orthorhombic system in a cell of dimensions a = 8.3390(17) Å, b = 13.259(3) Å, c = 56.023(11) Å (t = −120 °C). KTaTe₃ crystallizes with 20 formula units (or 4 formula units of K₅Ta₅Te₁₅) in the monoclinic space group P2₁/c in a cell of dimension a = 7.7177(15) Å, b= 13.826(3) Å, c = 30.981(6) Å, and β = 90.11(3)° (t = −120 °C). Each structure consists of infinite anionic chains of Ta-containing polyhedra well separated by K⁺ cations. In K₁₂Ta₆Se₃₅ there are Ta₂Se₁₁ units formed by the face sharing of two TaSe₇ elongated bipyramids. These Ta₂Se₁₁ units are in turn interconnected by Se₂ and Se₃ units to form _α¹[Ta₆Se₃Se₃₅¹²⁻]infinite chains. In KTaTe₃, the _α¹[TaTe₃⁻] infinite chains arise from the face sharing of distorted TaTe₆ octahedra.     

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)°.     

Synthesis and structure of the platinum complexes [Bu4N]+[PtBr5(DMSO)]?, [Ph4P]+[PtBr5(DMSO)]?, and [Ph3(n-Am)P]+[PtBr5(DMSO)]?

The complexes [Bu₄N]₂⁺[PtBr₆]²⁻ (I), [Ph₄P]₂⁺[PtBr₆]²⁻ (II), and [Ph₃(n-Am)P]₂⁺ (III) are synthesized by the reactions of tetrabutylammonium bromide, tetraphenylphosphonium bromide, and triphenyl(n-amyl)-tetraphenylphosphonium bromide, respectively, with potassium hexabromoplatinate (mole ratio 2: 1). After recrystallization from dimethyl sulfoxide, complexes I, II, and III transform into [Bu₄N]⁺[PtBr₅(DMSO)]⁻ (IV), [Ph₄P]⁺[PtBr₅(DMSO)]⁻ (V), and [Ph₃(n-Am)P]⁺[PtBr₅(DMSO)]⁻ (VI). According to the X-ray diffraction data, the cations of complexes IV–VI have a slightly distorted tetrahedral structure. The N-C and P-C bond lengths are 1.492(7)–1.533(6) and 1.782(10)–1.805(10) ?, respectively. The platinum atoms in the mononuclear anions are hexacoordinated. The dimethyl sulfoxide ligands are coordinated with the Pt atom through the sulfur atom (Pt-S 2.3280(18)–2.3389(11) ?). The Pt-Br bond lengths are 2.4330(6)–2.4724(6) ?.     

Synthesis, crystal structures, phase transition characterization and thermal decomposition of a new dabcodiium hexaaquairon(II) bis(sulfate): (C6H14N2)[Fe(H2O)6](SO4)2

The crystal structures of 1,4-diazabicyclo[2.2.2]octane (dabco)-templated iron sulfate, (C₆H₁₄N₂)[Fe(H₂O)₆](SO₄)₂, were determined at room temperature and at −173 °C from single-crystal X-ray diffraction. At 20 °C, it crystallises in the monoclinic symmetry, centrosymmetric space group P2₁/n, Z=2, a=7.964(5), b=9.100(5), c=12.065(5) Å, β=95.426(5)° and V=870.5(8) ų. The structure consists of [Fe(H₂O)₆]²⁺ and disordered (C₆H₁₄N₂)²⁺ cations and (SO₄)²⁻ anions connected together by an extensive three-dimensional H-bond network. The title compound undergoes a reversible phase transition of the first-order at −2.3 °C, characterized by DSC, dielectric measurement and optical observations, that suggests a relaxor–ferroelectric behavior. Below the transition temperature, the compound crystallizes in the monoclinic system, non-centrosymmetric space group Cc, with eight times the volume of the ambient phase: a=15.883(3), b=36.409(7), c=13.747(3) Å, β=120.2304(8)°, Z=16 and V=6868.7(2) ų. The organic moiety is then fully ordered within a supramolecular structure. Thermodiffractometry and thermogravimetric analyses indicate that its decomposition proceeds through three stages giving rise to the iron oxide.     

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.     

A route to novel stable salts containing transition and main group metals

Novel salts of the type [Cu(Dien)₂][Bu₃SnCl₃], [Cu(Dien)₂][Ph₂SnCl₄], and [Cu(Dien)₂][SnCl₆] (Dien—diethylenetriamine) were prepared by the reaction of [Cu(Dien)₂]Cl₂ with Bu₃SnCl, Ph₂SnCl₂ and SnCl₄ in MeOH in a 1:1 ratio, respectively, and characterized by elemental analyses, electronic, IR and ESR spectroscopy, magnetic susceptibility, electrochemistry, and conductivity measurements. The results revealed that the compounds are 1:1 electrolytes and the Cu²⁺ ion is paramagnetic in the octahedral field. The complexes exhibit a single-electron redox couple. The article was submitted by the authors in English.     

Heterobimetallic complexes of palladium(II) bridged by the mixed phosphine–phosphine oxide ligand Ph2PCH2CH2P(O)Ph2

The mixed phosphine–phosphine oxide Ph₂PCH₂CH₂P(O)Ph₂ (dppeO) reacts with either trans-[PdCl₂(PhCN)₂], Na₂[PdCl₄] or trans-[PdCl₂(DMSO)₂] to give trans-[PdCl₂{¹-Ph₂PCH₂CH₂P(O)Ph₂}₂]. Treatment of the latter with the metal chlorides, MCl₂ · nH₂O (M = Mn, Cu, Co, Zn, Hg; n = 4, 2, 6, 1, 0, respectively) or with Me₂SnCl₂ or SnCl₄ · 5H₂O, or with UO₂(NO₃)₂ · 6H₂O or UO₂(OAc)₂ · 2H₂O gives heterobimetallic complexes: trans-[PdCl₂{-Ph₂PCH₂CH₂P(O)Ph₂}₂MX₂] · nH₂O. The cobalt complex (MX₂ = CoCl₂) was unstable in solution (MeOH or EtOH/CHCl₃), and reverts to trans-[PdCl₂{¹-Ph₂PCH₂CH₂P(O)Ph₂}₂] and CoCl₂. trans-[PdCl₂{¹-Ph₂PCH₂CH₂P(O)Ph₂}₂] does not apparently react with either NiCl₂ · 6H₂O or CdCl₂ · 2.5H₂O.     

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.]     

Isolation of p-tricyanovinylphenyldicyanomethide ion via a [2+2] cycloaddition of 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules

In the presence of CoCl₂·6H₂O and dppm (bis(diphenylphosphino) methane), the reaction of TCNQ (7,7,8,8-tetracyanoquinodimethane) molecules by [2+2] cycloaddition forms a p-tricyanovinylphenyldicyanomethide ion (PCQ⁻), which has been obtained as one anion unit in one new compound [Co(dppmdo)₃][PCQ⁻]₂·H₂O 1 (dppmdo = bis(diphylphospine oxide) methane). Its structure was determined by X-ray crystallography: 1 crystallizes in with a = 14.174(3) Å, b = 19.553(4) Å, c = 19.776(4) Å, α = 112.72(3)°, β = 95.43(3)°, γ = 110.79(3)°, and Z = 2. It was characterized by IR spectra, UV–Vis spectra, and cyclic voltammogram. Magnetic properties indicate that no magnetic coupling between PCQ⁻ and [Co(dppmdo)₃]²⁺ unit.     

PROTONATED LIGAND OUTER-SPHERE COMPLEX FORMED IN THE REACTION OF 6-METHYLPYRIDINE-2-CARBOXALDEHYDE PHENYLHYDRAZONE WITH Ph2SnCl2. A TRUE CASE OF HYDROGEN BONDING INVOLVING AN Sn-CI BOND

Abstract

The reaction of 6-methylpyridine-2-carboxaldehyde phenylhydrazone (L) with Ph₂SnCl₂ has resulted in the formation of a complex salt [LH⁺]₂[Ph₂SnCl₄]^2-. X-ray diffraction studies on the salt reveal the structure of the [Ph₂SnCl₄] dianion to be centrosymmetric with the tin atom in a distorted octahedral trans-C₂Cl₄ environment; Sn-Cl(1) 2.598(2), Sn-Cl(2) 2.5875(7) and Sn-C(1) 2.146(3) Å. Associated with the dianion are two [PhN(H)NC(H)C₅H₃(Me)N(H)] cations via two hydrogen bonding contacts apiece, unusually involving a true Sn-Cl bond.     

Synthesis, structure, and reactions of the first homoleptic lithium-arsenic compound, [Li(μ-AsR2)]3 (R = CH(SiMe3)2)

Reaction of Li with AsClR₂ (R = CH(SiMe₃)₂) affords [Li(μ-AsR₂]₃ (I), the first structurally characterised dialkylarsenide, which in OEt₂ at 25°C yields AsHR₂, AsMeR₂, AsHR₂, or A^.sR₂ (II) with HCl, MeCl, Bu^tCl, or SnCl₂, respectively; upon removal of solvent, II furnishes As₂R₄ (III), which readily dissociates into II: the As₃Li₃ ring of I has a boat conformation and the average Li---As bond distance is 2.60(4) Å.