Synthesis of azoxybenzene-SbCl5 complexes and their selective ortho-wallach rearrangement

When an equimolar solution of various azoxybenzenes and SbCl₅ in carbon tetrachloride were mixed, a 1:1 complex immediately deposited as orange crystals in high yield. The thermal reaction of these complexes in inert solvents gives o-hydroxy-azobenzene selectively. On the contrary, other Lewis acids such as TiCl₄, AlCl₃, FeCl₃ and ZnBr₂ failed to give an isolatable complex with azoxybenzene, and their direct thermal reaction with azoxybenzene resulted in deoxygenation to yield azobenzene as a main product.     

Molecular complexation of free base meso-tetraarylporphyrins with antimony(III) chloride in free solvent media

The reaction of meso-tetraarylporphyrins (H₂t(Xp)p) with SbCl₃ under free solvent conditions affords green complexes with a 1:1 H₂t(X)pp:SbCl₃ ratio. These complexes have dimeric structures with a (μ-Cl)₂bridge. UV–VIS, ¹H NMR and ¹³C NMR spectra data show that the porphyrin core of [(H₂t(Xp)p)₂Sb₂Cl₆], similar to 1:2 (donor:acceptor) molecular complexes of meso-tetraarylporphyrins and porphyrin diacid, is distorted, thus two nitrogen atoms of pyrrolenine in a side of the porphyrin plane act as electron donors to an antimony atom of SbCl₃. Molecular complexation of meso-tetraarylporphyrins with SbCl₃ produces a large downfield shift for the NH signal, although there is no hydrogen bonding present.     

Darstellung von Cyclischen SbV–N-Verbindungen

Synthesis of Cyclic Sb^V-N-Compounds The preparation of cyclic Sb^V–N-compounds by oxidative amination of SbCl₃ with N-chloramides and by thermolysis of N-silylated amides with SbCl₅ in polar aprotic solvents under mild conditions is reported.     

Hexachlorantimonate(V) mit Nitroverbindungen als Liganden, 1. Mitt.: Komplexverbindungen mit einwertigen Metallen

Hexachloroantimonates with nitroderivatives as ligands on the cations are formed in a double complexation reaction of a mono-valent metal chloride (LiCl, NaCl, KCl, CuCl) with SbCl₅, and a nitroderivativeL (nitromethane, nitrobenzene, α-nitronaphthalene). Solid complexes of the typeML(SbCl₆) andML ₂(SbCl₆) were isolated. Synthesis, analytical results andi.r. spectra are discussed.     

Structures of molecular complexes of SbCl5 with pyridine and acetonitrile: equal bond lengths,different stability

Molecular structure of crystalline complex SbCl₅ ? Py was determined for the first time and the structure of the complex SbCl₅ ? AN was refined by means of single crystal X-ray diffraction analysis. It is shown that donor-acceptor Sb–N bond lengths for these complexes are equal within the experimental error. Quantum chemical calculations of the complexes in the gas phase reveal that the energies of the donor-acceptor bond Sb–N are 88 and 180 kJ mol^?1 for SbCl₅ ? AN and SbCl₅ ? Py, respectively. It is established that the length of the donor-acceptor bond Sb–N in the crystal cannot serve as a measure of its strength.

     

A calorimetric study of the interaction of H2O·SbCl5 and HCl-SbCl,with weak organic bases in 1,2-dichloroethane

The enthalpies of interaction between H₂O·SbCl₅ and the oxygen bases DMA, n-Pr₂O, MePrCO, and EtOAc to form ternary complexes D·H₂O-SbCl₅ in 1,2-dichloroethane solution have been determined calorimetrically. Reaction of water with the binary adducts D·SbCl₅;, result in the formation of the same ternary complexes which has been confirmed by PMR spectroscopic experiments. The base molecules are considered to be strongly H-bonded to the H₂O-SbCl₅ adduct in the complexes in solution.The enthalpy of formation of H₂O-SbCl₅ in 1,2-dichloroethane solution has been redetermined.The enthalpies of formation of the [DH]⁺SbCl^?₆ and [D₂H]+SbCl^?₆ complexes from the complex acid HCl-SbCl₅ and Pr₂O, MePrCO and (MeO)₂CO have been determined and estimates of the association constant for the formation of the [DH]⁺SbCl^?₆ complexes from the D·SbCl₅, adducts have been derived for D = MePrCO, EtOAc and (MeOP₂CO.Measurements of the interaction between HCl-SbCl₅ and the protogenic ligands PrOH and H₂O were also made.     

Synthesis and Characterization of the Lewis Acid‐Base Complexes SbCl5 · LB (LB = ICN,BrCN, ClCN, 1/2(CN)2, NH2CN,Pyridine) – a Combined Theoretical and Experimental Investigation. The Crystal Structures of SbCl5 · NCCl and SbCl5 · NCCN · SbCl5

The Lewis acid‐base complexes SbCl₅ · LB (LB = ICN, BrCN, ClCN, ¹/₂(CN)₂, NH₂CN, pyridine) were prepared. The products formed were characterized by Raman and NMR spectroscopy. Density functional theory (B3LYP) was applied to calculate structural and vibrational data. Vibrational assignments of the normal modes for these Lewis acid‐base adducts was made on the basis of their Raman spectra in comparison with computational results. The stability of the complexes was investigated by calculating the bond dissociation enthalpy. SbCl₅ · NCCl and SbCl₅ · NCCN · SbCl₅ were characterized by X‐ray structural analysis. NBO analyses were performed on the crystallographic data.     

Thermodynamic studies of sitting-atop complexation between free base meso-tetraarylporphyrins and antimony(III) chloride in chloroform

Interaction of para, meta and ortho-substituted meso-tetraarylporphyrins, (H₂t(X)pp, X: OMe, Me, H and Cl) with SbCl₃ in chloroform solution afforded 1 : 1 sitting-atop (SAT) complexes ([(SbCl₃)(H₂t(X)pp)]). The formation constants were calculated by KINFIT and found to decrease with increasing temperature. The thermodynamic parameters, ΔH°, ΔS° and ΔG°, were obtained. Formation constants of these complexes change with changing substituent (X) on the aryl rings of H₂t(X)pp in the following order: (SbCl₃)H₂t(4-OMe)pp >?(SbCl₃)H₂t(4-Me)pp >?(SbCl₃)H₂tpp >?(SbCl₃)H₂t(4-Cl)pp >?(SbCl₃)H₂t(3-OMe)pp >?(SbCl₃)H₂t(3-Me)pp> (SbCl₃)H₂t(2-OMe)pp >?(SbCl₃)H₂t(2-Me)pp.     

Die Simultanintercalation von Antimonpentachlorid mit einigen Metalltrichloriden in das Graphitgitter

Simultaneous Intercalation of Antimony Pentachloride with Metal Trichlorides into Graphite The metal trichlorides AsCl₃, SbCl₃, BiCl₃, AlCl₃, GaCl₃, and FeCl₃ intercalate simultaneously with SbCl₅ into the graphite lattice forming intercalation compounds of a SbCl₅: MCl₃ ratio between 1:0.16 and 1:4.5. C₂₄SbCl₅(AsCl₃)_0.9 as well as C₆₀SbCl₅(GaCl₃)_4·5 are already formed by a spontaneous intercalation at 25°C. During co-intercalation of SbCl₅ with BiCl₃ and AlCl₃, respectively, the ratios SbCl₅:MCl₃ decrease with increasing intercalation time. X-ray and EPMA measurements suggest that homogeneous mixtures of SbCl₅ and trichlorides are inserted in the interlayer galleries. The identity periods along c-axis of the stage 1 and stage 2 compounds are I_c = 9.30—9.39 Å and I_c = 12.58—12.76 Å, respectively. In stage 1 SbCl₅/AsCl₃-graphite as well as SbCl₅/GaCl₃-graphite a simultaneous desintercalation of SbCl₅ and MCl₃ have been found in vacuum and by solvents. The successive stage increase during thermal deintercalation was investigated by thermogravimetric methods. Mass spectroscopic gas analysis of the pyrolysis products show that the thermal dissociation of SbCl₅ superimposes stage transformations.     

Spectres RQN de quelques complexes d'addition molẃculaires de SbCl5 avec des coordinats oxodonneurs

NQR spectra of the SbCl₅(DMF). SbCl₅(OSCl₂), SbCl₅(OSeCl₂), and SbCl₅(OVCl₃) adducts are reported and discussed. A scale of the donor strength of the ligands based on the comparison of these spectra with those of SbCl₅(OPCl₃) and SbCl₃,(C₆H₅COCl) is proposed: VOCl₃ < SOCl₂ < C₆H₅COCl < POCl₃ < SeOCl₂. Furthermore, the data are consistent with a C₅ symmetry for the SbCl₅(OSCl₂) adduct.     

Acidité dans le nitrométhane: IV. Étude électrochimique des complexes chlorures de l'antimoine(III et V). HSbCl6

The electrochemical behavior of SbCl₃ and SbCl₅ is studied in nitromethane. SbCl₃ and SbCl₅ are Cl^? acceptors, giving respectively SbCl₄/^? (log K formation=4), and SbCl₆ (log K formation=15). Formal potentials of systems are determined. SbCl₅ reacts with HCl, giving the solvated proton H_S/⁺ and SbCl₆/^?; it is not possible to determine the formal potential of the hydrogen electrode, using HSbCl₆ as an acid, because the reduction of Sb^v occurs before the reduction of H_S/⁺.     

Reaktionsprodukte aus Chlormethoxiphosphinen und Antimon(V)-chlorid. Schwingungsspektren der 1:1 Addukte aus Methoxiphosphorylverbindungen und Antimon(V)-chlorid

Reaction Products of Chloromethoxiphosphines and Antimony (V) Chloride. Vibrational Spectra of the 1:1-adducts of Methoxiphosphoryl Compounds and Antimony (V) Chloride Chloromethoxiphosphines react with antimony(V) chloride in a redox process to yield the chloromethoxiphospllonium hexachloroantimonates(V) (CH₃O)₃PCl₂⁺SbCl₆^? (II) and CH₃OPCl₃⁺SbCl₆^? (III). II, III, (CH₃O)₃PCl⁺SbCl₆^?(1) and (CH₃O)₄P⁺SbCl₆^? eliminate easily methyl chloride and give the addition compounds OP(OCH₃)₃·SbCl₅(IV), OPCl(OCH₃)₂ · SbCl₅ (V), OPCl₂(OCH₃)·SbCl₅ (VI) and OPCl₃·SbCl₅ (VII). The vibrational spectra of IV, V nnd VI are discussed.     

Atom-atom interaction model and internal vibrational exciton splittings in organic charge-transfer complexes: Factor group splittings of naphthalene vibrations in several crystalline complexes

Factor group splittings of naphthalene vibrations are experimentally investigated for naphthalene: 2SbCl₃ (C₁₀H₈ - 2SbCl₃), naphthalene: octafluoronaphthalene (C₁₀H₈ : C₁₀F₈), naphthalene: TCNB, and naphthalene: TNB crystalline complexes by Raman spectroscopy and using the isotopically mixed crystal technique. It is found that only 386 cm^?1 mode of C₁₀H₈ shows factor group splittings in the first two complexes. The splitting increases from 5 cm^?1 in pure C₁₀H₈ crystal to 5.5cm^?1 in C₁₀H₈ : 2SbCl₃ but decreases to 1cm^?1 in the C₁₀H₈ : C₁₀F₈ complex. Also as SbCl₃ is successively replaced by SbBr₃ in the complex C₁₀H₈ : 2SbCl₃, the factor group splitting of 386 cm^?1 C₁₀H₈ mode decreases and the mean of the factor group frequencies goes through a minimum near 0.5 mole fraction of SbBr₃. A theoretical calculation using atom-atom potential model and considering only naphthalene-naphthalene interactions predicts that the factor group splitting on 386 cm^?1 band should increase from pure C₁₀H₈ crystal to the C₁₀H₈ :2SbCl₃ crystalline complex and decrease in C₁₀H₈ : C₁₀F₈. However, the calculation also predicts a similar trend for 943 cm^?1 band of naphthalene which shows a factor group splitting of 5 cm^?1 in pure C₁₀H₈ but none in the C₁₀H₈ : 2SbCl₃ complex. Furthermore, the atom-atom interaction model does not explain the effect of SbBr₃ substitution on the factor group splitting. The importance of electrostatic multipole interactions in explaining the behavior of factor group splitting is discussed.     

Quantum chemical study of the arylacyl azide complexes with Lewis acids and their Curtius rearrangement to isocyanates

The structures of donor-acceptor complexes of syn-benzoyl azide, its 2-methyl- and 2,6-dimethyl-substituted derivatives with BF₃, AlCl₃, and SbCl₅, and the corresponding transition states of the rearrangement into isocyanates were studied by the PBE/TZ2P method in the framework of the density functional theory (DFT). The complexes are formed at the oxygen and nitrogen atoms of the acyl azide group and have the composition 1: 1 or 1: 2 depending on the Lewis acid (L) structure. The complexes at the oxygen atom are more stable; the most stable complexes are formed by the reactions of acyl azides with AlCl₃. Complex formation with Lewis acids decreases the activation energy of the transformation of acyl azides into isocyanates owing to the +M effect and stabilization of the Ar-C(O-L^(1?))=N(1)-N(2)⁽¹⁺⁾≡N(3) mesomeric form. The activation energy decreases with an increase in the number of ortho-methyl substituents in benzoyl azide due to the +I effect of the phenyl group. The turn of the phenyl ring at almost 90° with respect to the CON₃ group is needed for the rearrangement to occur, and the energy necessary for this process is ～8 kcal mol^?1.     

Kronenetherkomplexe von Blei(II). Die Kristallstrukturen von [PbCl(18-Krone-6)][SbCl6], [Pb(18-Krone-6)(CH3CN)3][SbCl6]2, and [Pb(15-Krone-5)2][SbCl6]2

Crown Ether Complexes of Lead(II). The Crystal Structures of [PbCl(18-Krone-6)][SbCl₆], [Pb(18-Krone-6)(CH₃CN)₃][SbCl₆]₂ und [Pb(15-Krone-5)₂][SbCl₆]₂ . [PbCl(18-crown-6)][SbCl₆] has been prepared in low yield besides [Pb(CH₃)₂(18-crown-6)][SbCl₆]₂ by the reaction of Pb(CH₃)₂Cl₂ with antimony pentachloride in acetonitrile solution in the presence of 18-crown-6, forming pale-yellow crystals. The other two title compounds are formed as colourless crystals by the reaction of PbCl₂ with antimony pentachloride in acetonitrile solutions in the presence of 18-crown-6 and 15-crown-5, respectively. The complexes were characterized by IR spectroscopy and by crystal structure determinations. [PbCl(18-crown-6)][SbCl₆]: Space group P2₁/c, Z = 8, 5 003 observed unique reflections, R = 0.046. Lattice dimensions at - 80°C: a = 1 386.9; b = 1 642.7; c = 2 172.1 pm, β = 92.95°. The lead atom in the cation [PbCl(18-crown-6)]⁺ is surrounded in an almost hexagonal-planar construction by the six oxygen atoms of the crown ether and an axially oriented Cl atom. [Pb(18-crown-6)(CH₃CN)₃][SbCl₆]₂: Space group P1 , Z = 2, 6 128 observed unique reflections, R = 0.076. Lattice dimensions at - 70°C: a = 1 228.0; b = 1 422.9; c = 1 463.2 pm, α = 69.08°; β = 65.71°; γ = 64.51°. In the cation [Pb(18-crown-6)(CH₃CN)₃]²⁺ the lead atom is coordinated by the six oxygen atoms of the crown ether and by the three nitrogen atoms of the acetonitrile molecules. The structure determination is restricted by disorder. [Pb( 15-crown-5)₂][SbCI₆]₂: Space group P6₃/m, Z = 6, 5 857 observed unique reflections, R = 0.059. Lattice dimensions at -70°C: a = b = 2 198.5; c = 1499.4 pm, α = β = 90°, γ = 120°. In the cation [Pb(l5-crown-5)₂]² the lead atom is sandwich-like coordinated by the ten oxygen atoms of the two crown ether molecules. The structure determination is restricted by disorder.     

Vibrational spectra and normal coordinate analyses of the trimethyloxonium and trimethylammonium cations

Raman and i.r. spectra of the compounds (CH₃)₃O⁺ SbCl⁻₆ and (CH₃)₃NH⁺ SbCl⁻₆ are reported and assigned. Normal coordinate calculations support the vibrational assignments for the cations Of C_3v symmetry, and yield force constants k(CO) = 4.05 mdyn·Å⁻¹ and k(CN) = 4.80 mdyn·Å⁻¹ for the trimethyloxonium ion and the trimethylammonium ion, respectively.     

Synthese und Struktur von [(Me2PhP)3Cl2ReN]2ReCl4, [(Me2PhP)3Cl2ReN]2ReCl4 · 2 SbCl3 und [Re(NH)Cl2(PMe2Ph)3][SbCl6]

Synthesis and Structure of [(Me₂PhP)₃Cl₂ReN]₂ReCl₄, [(Me₂PhP)₃Cl₂ReN]₂ReCl₄ · 2 SbCl₃ and [Re(NH)Cl₂(PMe₂Ph)₃][SbCl₆] The reaction of ReNCl₂(PMePh)₃ with SbCl₅ in toluene yields the trinuclear complex [(Me₂PhP)₃Cl₂Re≡N]₂ReCl₄ · 2 SbCl₃ ( 1 · 2 SbCl₃). It forms triclinic crystals with the composition 1 · 2 SbCl₃, as well as monoclinic crystals 1 · 2 SbCl₃ · 4 C₇H₈. The monoclinic crystals with the space group P2₁/c, and a = 1212.3(2), b = 2098.5(4), c = 1827.7(3) pm, β = 95.51(1)°, Z = 2, have been used for a crystal structure determination. In the centrosymmetric complex 1 two complexes ReNCl₂(PMe₂Ph)₃ coordinate with their nitrido ligands a square planar, central unit ReCl₄. The SbCl₃ molecules are coordinated by chlorine bridges to Cl atoms of 1 , and, in addition, connect the complexes 1 with each other. The SbCl₃ free compound 1 is obtained in good yield by the reaction of ReNCl₂(PMePh)₃ with ReCl₄(NCEt)₂. It crystallizes in the triclinic space group P1 with a = 1037.7(3), b = 1153.0(2), c = 1393.8(3) pm, α = 72.31(2)°, β = 74.06(2)°, γ = 67.94(2)°, and Z = 1. The bond lengths of the Re–N triple bonds are 172 pm in 1 and 170 pm in 1 · 2 SbCl₃. By the reaction of ReNCl₂(PMePh)₃ with SbCl₅ in CH₂Cl₂ the solvent is decomposed forming HCl which protonates the nitrido ligand to afford the imido complex [Re(NH)Cl₂(PMe₂Ph)₃][SbCl₆] ( 2 ) crystallizing in the monoclinic space group P2₁/n with a = 1221.4(2), b = 1358.6(2), c = 2177.3(1) pm, β = 92,72(1)° and Z = 4. The Re–N distance in the almost linear unit Re≡N–H is 169,1 pm.     

Die Kristallstruktur und das Raman-Spektrum von SbCl3 · S8

Crystal Structure and Raman Spectrum of SbCl₃ · S₈ Contrary to literature data, the reaction of SbCl₅ with CS₂ at 5°C does not yield SbSCl₃ but SbCl₃ · S₈. At room temperature it already decomposes slowly to SbCl₃ and sulphur. The crystalline compound is built up from pyramidal SbCl₃ molecules and S₈ rings; pairs of SbCl₃ molecules form loosely associated dimeric units, furthermore there exist some relatively short Sb…?S contact distances. SbCl₃ · S₈ crystallizes in the space group P1 with the lattice constants a = 805, b = 867, c = 1073 pm, α = 94.9, β = 107.1 und γ = 111.6° (bei ?5°C). The crystal structure was determined with 2032 X-ray reflexions and was refined to a residual index of R = 0.028. The Raman spectrum is reported.     

Synthesis and spectroscopic study of complexes of antimony pentachloride with some benzonitrile derivatives

The complexes SbCl₅ · L (L = 2,3 and 4-chlorobenzonitriles and 2,3 and 4-aminobenzonitriles) have been isolated and investigated by conductivity and IR and Raman spectral measurement. From the IR spectra it is inferred that in all complexes, coordination of the ligands to the Sb takes place through the nitrogen atom of the nitrile group. In addition, the spectral data are in full accord with a molecular adduct of local C_4v symmetry for the SbCl₅N moiety.     

<Superscript>35</Superscript>Cl NQR for the SbCl<Subscript>3</Subscript> complex with aniline,SbCl<Subscript>3</Subscript>·NH<Subscript>2</Subscript>C<Subscript>6</Subscript>H<Subscript>5</Subscript>

The temperature dependence of the ³⁵Cl NQR frequencies and spin-lattice relaxation times has been investigated for a trigonal-bipyramidal vn complex SbCl₃·NH₂C₆H₅. Thermally activated motion of chlorine atoms (pseudorotation) was not revealed in the complex, in contrast to the vπ complexes of SbCl₃ with related molecular structures. The high potential barrier of pseudorotation in the aniline complex is likely to be due to the unusually high nonequivalence of Sb-Cl chemical bonds.