Dichloracetylen als stabiler Komplexligand Die Kristallstruktur von PPh4[WCl5(C2Cl2)] · 0,5 CCl4

Dichloro Acetylene as Complex Ligand. Crystal Structure of PPh₄[WCl₅(C₂Cl₂)] · 0.5 CCl₄ Tungsten hexachloride and dichloro acetylenediethyletherate react in boiling CCl₄ in presence of C₂Cl₄ as reducing agent forming [Et₂O · WCl₄(C₂Cl₂)]. In vacuo the complex looses ether giving the dichloro acetylene complex [WCl₄(C₂Cl₂)]₂ which is dimeric with chloro bridges. Both complexes react with tetraphenylphosphonium chloride to form PPh₄[WCl₅(C₂Cl₂)] which is equally prepared by ligand exchange of PPh₄[WCl₅(C₂I₂)] with silver chloride. All dichloro acetylene complexes are red to brown crystalline solids sensitive to moisture, and are thermally and mechanically very stable compared with the highly explosive dichloro acetylene. The compounds are characterized by their i.r. spectra; [Et₂O · WCl₄(C₂Cl₂)] was additionally investigated by ¹³C-nmr spectroscopy. PPh₄[WCl₅(C₂Cl₂)] · 0.5 CCl₄ formes dark brown crystals; according to the structural investigation by X-ray diffraction methods the compound crystallizes orthorhombic in the space group Pbca with 8 formula units per unit cell (1317 observed, independent reflexions, R = 0.049). The cell dimensions are a = 1702 pm, b = 1675 pm and c = 2228 pm. The compound consists of [WCl₅(C₂Cl₂)]? anions and PPh₄⊕ cations including CCl₄ molecules without bonding interactions. The tungsten atoms are seven-coordinated by five chlorine atoms and two carbon atoms. The dichloro acetylene ligand is bonded symmetrically side-on and has a C? C bond length of 128 pm. The W? C distances are 201 pm, the four equatorial Cl atoms have W? Cl bond lengths of 234 pm whereas the chlorine atom in trans-position to the W? C₂ group is situated in a distance of 244 pm.     

Thiochlorowolframate von Wolfram(V) und -(VI). Die Kristallstrukturen von PPh4[WSCl4] und (PPh4)2[WS2Cl4] · 2 CH2Cl2

Thiochlorowolframates with Tungsten(V) and (VI). Crystal Structures of PPh₄[WSCl₄] and (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂ Diamagnetic (NEt₄)₂[WSCl₄]₂, having tungsten atoms linked via sulfur atoms, is obtained by the reaction of WCl₅ with NEt₄SH as well as by the reduction of WSCl₄ with NEt₄I in dichloromethane. If the reduction is performed with PPh₄I, PPh₄[WSCl₄] with monomer anions is formed. Reaction of WCl₆ with H₂S in dichloromethane yields brown, insoluble WS₂Cl₂ which has terminal W?S groups and bridging W? S? W groups according to its IR spectrum. WS₂Cl₂ and PPh₄Cl react to afford PPh₄[WS₂Cl₃] · 2 CH₂Cl₂ and (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂. IR spectra are reported. The crystal structures of PPh₄[WSCl₄] and (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂ were determined by X-ray diffraction. PPh₄[WSCl₄]: tetragonal, space group P4/n, Z = 2, a = 1292.3 pm, c = 763.2 pm; R = 0.054 for 898 observed reflexions. The [WSCl₄]^? ion has the structure of a square pyramid with a rather short W?S bond of 206 pm length. (PPh₄)₂[WS₂Cl₄] · 2 CH₂Cl₂: triclinic, space group P1 , a = 1017.7, b = 1114.5, c = 1243.4 pm, α = 70.61, β = 79.73, γ = 80.80°; R = 0.076 for 1804 reflexions. The [WS₂Cl₄]^2? has cis configuration; as it is situated on an inversion center it shows positional disorder.     

Die Kristallstrukturen von [ReCl4(PhCCPh)]2 · 2 CH2Cl2 und von PPh4[ReOCl4]

Crystal Structures of [ReCl₄(PhC?CPh)]₂ · 2 CH₂Cl₂ and PPh₄[ReOCl₄] Single crystals of [ReCl₄(PhC?CPh)]₂ · 2 CH₂Cl₂ were obtained by chilling dilute solutions of the solvate [ReCl₄(PhC?CPh)POCl₃] in CH₂Cl₂. PPh₄[ReOCl₄] was formed by the reaction of the diphenyl acetylene complex [ReCl₅(PhC?CPh)] with PPh₄Cl · H₂O in CH₂Cl₂ solution. [ReCl₄(PhC?CPh)]₂ · 2 CH₂Cl₂: space group P2₁/c, Z = 2, 2244 observed independent reflexions, R = 0.038. Lattice parameters (19°C): a = 987.2 pm; b = 1533.9 pm; c = 1193.8 pm; β = 90.17° The compound forms centrosymmetrical dimeric molecules with ReCl₂Re bridges with Re? Cl distances of 241.2 and 267.6 pm. The longer Re? Cl bond is situated in trans-position to the equatorial, side-on coordinated diphenyl acetylene ligand with mean Re? C distances of 200 pm. PPh₄[ReOCl₄]: space group P4/n, Z = 2, 1487 observed, independent reflexions, R = 0.047. Lattice parameters (19°C): a = b = 1272.0 pm; c = 771.3 pm. The compound crystallizes in the AsPh₄[RuNCl₄] type; it consists of [ReOCl₄]^? anions and PPh₄⁺ cations. The anions are tetragonal with C_4v symmetry and bond lengths Re? O = 165.4 pm and Re? Cl = 232.6 pm; the bond angle OReCl is 106.7°.     

Diphenyl-diacetylen-Komplexe von Molybdän(IV) und Wolfram(IV). Die Kristallstrukturen von PPh4[WCl5(Ph?CC?CC?Ph)] · CCI4 und von PPh4[WCl5(Ph?CC?C(Br)C(Br)?Ph)] · CCl4

Diphenyldiacetylene Complexes of Molybdenum (IV) and Tungsten (IV). Crystal Structures of PPh₄[WCl₅(Ph? C?C? C?C? Ph)] · CCl₄ and PPh₄[WCl₅(Ph? C?C? C(Br)?C(Br)? Ph)] · CCl₄ Syntheses and i.r. spectra of the following diphenyldiacetylene complexes are reported: [MoCl₄(Ph? C?C? C?C? Ph)]₂( 1 ), [WCl₄(Ph? C?C? C?C? Ph)]₂ ( 2 ), PPh₄[WCl₅(Ph? C?C? C?C? Ph)] · CCl₄ ( 3 ). 1 is formed in the reaction of MoCl₅ with excess diphenyldiacetylene. 2 is prepared from WCl₆ and excess diphenylacetylene with additional C₂Cl₄ as a reducing agent. Reaction of 2 with PPh₄Cl in CH₂Cl₂ solution in the presence of CCl₄ yields 3 . The complexes contain one of the acetylene functions bonded in a metallacyclopropene ring; the metal atoms are seven-coordinated. 2 reacts with bromine to from the dibromide [WCl₄(Ph? C?C? C(Br)? Ph)]₂ (4). In CH₂Cl₂ solution and in presence of ccl₄ 4 is turned into the ionic complex PPh₄[Ph? C?C? C(Br)? Ph] · CCl₄ (5) by PPh₄Cl. The complexes 3 and 5 are characterized by structural analyses on the basis of X-Ray diffraction data. 3 crystallized monoclinic in the space group p2₁/n with four formula units per unit cell (2623 observed, independent reflexions, R = 5.4%). 5 crystallized in the same space group, set P2₁/c, the unit cell containing four formula units (2537 observed, independent reflexions, R = 5.4%). Both complexes consist of tetraphenylphosphonium cations and anions, in which the tungsten atoms are coordinated by five chlorine and two carbon atoms, the latter bonding side-on, in an approximately symmetrical way. In addition the lattices contain one molecule CCl₄ per formula unit. The acetylene ligand causes a strong trans-effect. As a result the W? Cl bond lengths in trans-position are by 10 pm longer than those in cis-position. Bromination of the second acetylene function of 3 leads to addition in trans-position (5).     

Addukte des Oxo-tetrachloro-niobat(V)-Ions Bildung,Schwingungsspektren und Kristallstrukturen von PPh4[NbOCl4(OH2)] und (PPh4)2[NbOCl4(O2PCl2)] · 2 CH2Cl2

Adducts of Oxotetrachloro-niobate (V). Formation, Vibrational Spectra, and Crystal Structures of PPh₄[NbOCl₄(OH₂)] and (PPh₄)₂[NbOCl₄(O₂PCl₂)] · 2 CH₂Cl₂ Crystalline (PPh₄)₂[NbOCl₄(O₂PCl₂)] · 2 CH₂Cl₂ was obtained by hydrolysis of PPh₄[NbSCl₄] in the presence of POCl₃ in CH₂Cl₂. Experiments to obtain the same compound from PPh₄Cl, POCl₃, NbCl₅, and H₂O yielded PPh₄[NbOCl₄(OH₂)]. I.R. spectra of both compounds are discussed. The crystal structure determinations with X-ray diffraction data in both cases show quadratic-pyramidal NbOCl₄^? ions to which a molecule of either H₂O or a PO₂Cl₂^? ion is attached in trans-position to the O atom. PPh₄[NbOCl₄(OH₂)]: tetragonal, space group P4/n, a = 1 308, c = 734 pm, Z = 2, packing as in the AsPh₄[RuNCl₄] type; refinement down to R = 0.046 for 681 reflexions. (PPh₄)₂[NbOCl₄(O₂PCl₂)] · 2 CH₂Cl₂: triclinic, space group P1 , a = 1172, b = 1187, c = 2105 pm, α = 88.40, β = 83.20, γ = 71.28°, Z = 2, packing similar as in (AsPh₄)₂[NbOCl₅] · 2 CH₂Cl₂; refinement to R = 0.059 for 2 502 reflexions.     

Ein- und zweikernige Dinitrosylkomplexe von Molybdän und Wolfram. Die Kristallstrukturen von (PPh3Me)2[WCl4(NO)2], (PPh3Me)2[MoCl3(NO)2]2 und von (PPh3Me)2[WCl3(NO)2]2

Mono- and Binuclear Dinitrosyl Complexes of Molybdenum and Tungsten. Crystal Structures of (PPh₃Me)₂[WCl₄(NO)₂], (PPh₃Me)₂[MoCl₃(NO)₂]₂, and (PPh₃Me)₂[WCl₃(NO)₂]₂ The complexes (PPh₃Me)₂[MCl₄(NO)₂] (M = Mo, W), and (PPh₃Me)₂[MCl₃(NO)₂]₂, respectively, are prepared by reactions of the polymeric compounds MCl₂(NO)₂ with triphenylmethylphosphonium chloride in CH₂Cl₂, forming green crystals. According to the IR spectra the nitrosyl groups are in cis-position in all cases. The tungsten compounds as well as (PPh₃Me)₂[MoCl₃(NO)₂]₂ were characterized by structure determinations with X-ray methods. (PPh₃Me)₂[WCl₄(NO)₂]: space group C2/c, Z = 4. a = 1874, b = 1046, c = 2263 pm, β = 119.99°. Structure determination with 3492 independent reflexions, R = 0.057. The compound consists of PPh₃Me^⊕ ions, and anions [WCl₄(NO)₂]^2? with the nitrosyl groups in cis-position (symmetry C_2v). (PPh₃Me)₂[WCl₃(NO)₂]₂: Space group C2/c, Z = 4. Structure determination with 2947 independent reflexions, R = 0.059. (PPH₃Me)₂[MoCl₃(NO)₂]₂: Space group P1 , Z = 1. a = 989, b = 1134, c = 1186 pm; α = 63.25°, β = 80.69°, γ = 69.94°. Structure determination with 3326 independent reflexions, R = 0.046. The compounds consist of PPh₃Me^⊕ ions, and centrosymmetric anions [MCl₃(NO)₂]₂^2?, in which the metal atoms are associated via MCl₂M bridges of slightly different lengths. One of the NO groups is in an axial position, the other one in equatorial position (symmetry C_2h).     

Die Kristallstrukturen der Hexachlorometallate NH4[SbCl6], NH4[WCl6], [K(18‐Krone‐6)(CH2Cl2)]2[WCl6]·6CH2Cl2 und (PPh4)2[WCl6]·4CH3CN

Crystal Structures of the Hexachlorometalates NH₄[SbCl₆], NH₄[WCl₆], [K(18‐crown‐6)(CH₂Cl₂)]₂[WCl₆]·6CH₂Cl₂ and (PPh₄)₂[WCl₆]·4CH₃CN The crystal structures of the title compounds were determined by single crystal X‐ray methods. NH₄[SbCl₆] and NH₄[WCl₆] crystallize isotypically in the space group C2/c with four formula units per unit cell. The NH₄⁺ ions occupy a twofold crystallographic axis, whereas the metal atoms of the [MCl₆]^— ions occupy a centre of inversion. There exist weak interionic hydrogen bridges. [K(18‐crown‐6)(CH₂Cl₂)]₂[WCl₆]·6CH₂Cl₂ crystallizes in the orthorhombic space group R3¯/m with Z = 3. The compound forms centrosymmetric ion triples, in which the potassium ions are coordinated with a WCl₃ face each. In trans‐position to it the chlorine atom of a CH₂Cl₂ molecule is coordinated so that, together with the oxygen atoms of the crown ether, coordination number 10 is achieved. (PPh₄)₂[WCl₆]·4CH₃CN crystallizes in the monoclinic space group P2₁/c with Z = 4. This compound, too, forms centrosymmetric ion triples, in which in addition the acetonitrile molecules are connected with the [WCl₆]^2— ion via weak C—H···Cl contacts.     

Synthese und Kristallstrukturen der Nitridodiolato-Osmate(VI) PPh4[OsNCl2(O2C2H4)] und PPh4[OsNCl2(O2C2Me4)] · 2 THF

Syntheses and Crystal Structures of the Nitridodiolato Osmates(VI) PPh₄[OsNCl₂(O₂C₂H₄)] and PPh₄[OsNCl₂(O₂C₂Me₄)] · 2 THF The title compounds were prepared by the reaction of PPh₄[OsNCl₄] with glycole and pinacole, respectively, in CH₂Cl₂ and THF, respectively, in the presence of triethylamine, forming orange-red single crystals. According to the crystal structure determinations the compounds have ionic structures. In the anions the nitrido ligand occupies the apical position of the distorted tetragonal pyramid, and the two chlorine atoms and the two oxygen atoms of the diolato ligands are in equatorial positions. PPh₄[OsNCl₂(O₂C₂H₄)] : Space group P2₁/n, Z = 4, 3 331 observed unique reflections, R = 0.031. Lattice dimensions at 19°C: a = 1 750.3, b = 816.8, c = 1 816.5 pm, β = 95.16°. PPh₄[OsNCl₂(O₂C₂Me₄)] · 2 THF : Space group P1 , Z = 2, 5 238 observed unique reflections, R = 0.051. Lattice dimensions at -80°C: a = 898.9, b = 1 405.1, c = 1 518.6 pm, α = 93.66°, β = 92.89°, γ = 92.51°.     

(PPh4)3Ag[WF5(C2I2)]2; synthese,IR-spektrum und kristallstruktur

The compound (PPh₄)₃Ag[WF₅(C₂I₂)]₂ is formed by the reaction of PPh₄[WCl₅(C₂I₂)] with an excess of silver fluoride in acetonitrile. The compound is soluble in CH₂Cl₂; when CCl₄ is added single red crystals are obtained. The complex is characterized by its IR spectrum and by an X-ray structural study (4060 observed, independent reflexions, R = 0.105). Crystal data: orthorhombic, space group P2₁2₁2, Z = 2, a 4464(2), b 1074(1), c 777,6(4) pm. The compound consists of PPh₄⁺ and Ag⁺ ions, and the anions [WF₅(C₂I₂)]²⁻, in which the tungsten atoms are seven-coordinated by five fluorine atoms and two carbon atoms. The diiodoacetylene ligand is symmetrically bonded sideways to the tungsten atom. The four equatorial F atoms have WF bond lengths of 191 pm, whereas the fluorine atom in trans-position to the WC₂ group is located 199 pm from the metal centre. The PPh₄⁺ ions are stacked in parallel columns.     

Reaktionen von Uranpentabromid Die Kristallstrukturen von PPh4[UBr6], PPh4 [UBr6] · 2CCl4, (PPh4)2[UBr6] · 4CH3CN und (PPh4)2[UO2Br4] · 2CH2Cl2

Reactions of Uranium Pentabromide. Crystal Structures of PPh₄[UBr₆], PPh₄[UBr₆] · 2CCl₄, (PPh₄)₂[UBr₆] · 4CH₃CN, and (PPh₄)₂[UO₂Br₄] · 2CH₂Cl₂ PPh₄[UBr₆] and PPh₄[UBr₆] · 2CCl₄ were obtained from UBr₅ · CH₃CN and tetraphenylphosphonium bromide in dichloromethane, the latter being precipitated by CCl₄. Their crystal structures were determined by X-ray diffraction. PPh₄[UBr₆]: 2101 observed reflexions, R = 0.090, space group C2/c, Z = 4, a = 2315.5, b = 695.0, c = 1805.2 pm, β = 96.38°. PPh₄[UBr₆] · 2CCl₄: 2973 reflexions, R = 0.074, space group P2₁/c, Z = 4, a = 1111.5, b = 2114.2, c = 1718.7 pm, β = 95.42°. Hydrogen sulfide reduces uranium pentabromide to uranium tetrabromide. Upon evaporation, bromide is evolved from solutions of UBr₅ with 1 or more then 3 mol equivalents of acetonitrile in dichlormethane yielding UBr₄ · CH₃CN and UBr₄ · 3CH₃CN, respectively. These react with PPh₄Br in acetonitrile affording (PPh₄)₂[UBr₆] · 4CH₃CN, the crystal structure of which was determined: 2663 reflexions, R = 0.050, space group P2₁/c, Z = 2, a = 981.8, b = 2010.1, c = 1549.3 pm, β = 98.79°. By reduction of uranium pentabromide with tetraethylammonium hydrogen sulfide in dichloromethane (NEt₄)₂[U₂Br₁₀] was obtained; (PPh₄)₂[U₂Br₁₀] formed from UBr₄ and PPh₄Br in CH₂Cl₂. Both compounds are extremely sensitive towards moisture and oxygen. The crystal structure of the oxydation product of the latter compound, (PPh₄)₂[U0₂Br₄]· 2 CH₂Cl₂, was determined: 2163 reflexions, R = 0.083, space group C2/c, Z = 4, a = 2006.3, b = 1320.6, c = 2042,5 pm, β = 98.78°. Mean values for the UBr bond lengths in the octahedral anions are 266.2 pm for UBr₆-, 276.7 pm for UBr₆^2? and 282.5 pm for UO₂Br₄^2?     

Cyclothiazenokomplexe von Molybdän(V) und (VI), sowie von Wolfram(VI) Die Kristallstruktur von (PPh4)2[MoCl3(N3S2)]2 · 2 CH2Cl2

Cyclothiazeno Complexes of Molybdenum(V), Molybdenum(VI), and Tungsten(VI). Crystal Structure of (PPh₄)₂[MoCl₃(N₃S₂)]₂ · 2 CH₂Cl₂ . From excess trithiazylchloride and molybdenum or tungsten hexacarbonyl, respectively, the cyclothiazeno complexes [MCl₃(N₃S₂)]₂(S₂N₂) are obtained. They possess metal atoms linked via a planar S₂N₂ ring. The corresponding bromo compounds [MBr₃(N₃S₂)]₂(S₂N₂) can be obtained in liquid bromine from S₄N₄ and MoBr₄ or WBr₆, respectively, or from S₄N₄ with the corresponding metal hexacarbonyls in the presence of bromine. Thermolysis of [WBr₃(N₃S₂)]₂(S₂N₂) yields [WBr₃(N₃S₂)]₂ which is dimerized via nitrogen bridges. When [MoCl₃(N₃S₂)]₂(S₂N₂) reacts with tetraphenylphosphonium chloride in dichloromethane, the S₂N₂ acts as reducing agent, and the paramagnetic molybdenum(V) complex (PPh₄)₂[MoCl₃(N₃S₂)]₂ · 2 CH₂Cl₂ is obtained (μ_eff = 1.2 B.M.). The i.r. spectra are reported. The crystal structure of (PPh₄)₂[MoCl₃(N₃S₂)]₂ · 2 CH₂Cl₂ was determined by X-ray diffraction (2524 independent reflexions, R = 0.052). It crystallizes in the space group P1 with the lattice con- stants a = 943.9, b = 1209.6, c = 1469.2 pm, α = 69.27, β = 72.20 and γ = 82.08°, Z = 1. There are tetraphenylphosphonium cations and centrosymmetric, dimeric anions [MoCl₃(N₃S₂)]₂^2?. The molybdenum atoms are part of six-membered cyclothiazeno rings MoN₃S₂ with MoN bond lengths of 177 and 197 pm; the N atom with the longer MoN bond is linked to the second Mo atom, so that a planar Mo₂N₂ ring results; this ring is nearly coplanar with the two MoN₃S₂ rings. Furthermore, each molybdenum atom is linked with three chlorine atoms with MoCl bond lengths of 240–242 pm, so that the Mo atoms possms a distorted octahedral coordination.     

Thiohalogeno-Verbindungen von Niob und Tantal: NbSCl3, TaSCl3, [NbSCl5]2−, [TaSCl5]2−, [NbSBr4]− Die Kristallstrukturen von (PPh4)2[NbSCl5] · 2 CH2Cl2 und NEt4[NbCl6]

Thiohalo Compounds of Niobium and Tantalum: NbSCl₃, TaSCl₃, [NbSCl₅]^2?, [TaSCl₅]^2?, [NbSBr₄]^?. Crystal Structures of (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂ and NEt₄[NbCl₆] NbSCl₃ can be obtained from NbCl₅ by reaction with H₂S or bistrimethylsilyl sulfide in a suspension of CCl₄ or CH₂Cl₂, respectively; in the latter case the product contains a rest of trimethylsilyl groups. This also applies for TaSCl₃, NbSBr₃ and TaSBr₃, which are formed from the metal pentahalides and S(SiMe₃)₂. NEt₄[NbSCl₄] is formed together with NEt₄[NbCl₆] in the reaction of NbCl₅ with NEt₄SH in CH₂Cl₂. PPh₄[NbCl₆] reacts with S(SiMe₃)₂ in dichloromethane yielding (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂, whereas PPh₄[NbSBr₄] is obtained from PPh₄[NbBr₆] and S(SiMe₃) under the same conditions. (PPh₄)₂[TaSCl₅] · 2 CH₂Cl₂ was obtained from TaSCl₃ and PPh₄Cl in CH₂Cl₂. According to an X-ray crystal structure determination (PPh₄)₂[NbSCl₅] · 2 CH₂Cl₂ crystallizes in the β-(AsPh₄)₂[UCl₆] · 2 CH₂Cl₂ type with positionally disordered, octahedral anions. Crystal data: a = 1 021.7, b = 1120.4, c = 1 243.3 pm, α = 70.77, β = 80.24, γ = 80.54°, space group P1 , Z = 2; 2462 unique observed reflexions, R = 0.036. NEt₄[NbCl₆] crystallizes isotypic to NEt₄[WCl₆], a = 723.5, b = 1 018.0, c = 1 174.6 pm, β = 100.07°, space group P2₁/n, Z = 2; 1 875 reflexions, R = 0.075.     

Die Kristallstruktur von (PPh4)2[Mo2(O2C?Ph)4Br2] · 2 CH2Br2

Crystal Structure of (PPh₄)₂[Mo₂(O₂C? Ph)₄Br₂] · 2 CH₂Br₂ The title compound, prepared by the reaction of Mo₂(O₂C? Ph)₄ with PPh₄Br and PPh₄N₃, respectively, under the assistance of CH₂Br₂, was characterized by an X-ray structure determination. Space group P2₁/n, Z = 2, R = 0.074 (5261 independent observed reflexions). The lattice dimensions are at ?70°C: a = 1562.9, b = 1406.2, c = 1662.1 pm, β = 94.11°. the compound consists of PPh₄^⊕ ions, CH₂Br₂ molecules, and centrosymmetric anions [Mo₂(O₂C? Ph)₄Br₂]^2?. The axis Br? Mo?Mo–Br is nearly linear (bond angle 175.6°) with bond lengths MoMo = 212.3 pm and Mo? Br = 303 pm, corresponding with a weak electrostatic Mo? Br bond. In the FIR spectrum the Mobr stretching vibration is found at 85 cm^?1, which corresponds with the low value of the force constant of 0.24 N · cm^?1.     

Über die Reaktion von 2,2-Dimethylpropylidinphosphan mit Wolframhexachlorid; die Kristallstrukturen von [(Cl3PO)WCl4(H9C4?CC?C4H9)] und [(H5C6)4As][WCl6]

Reaction of 2,2-Dimethylpropylidynephosphane with Tungsten Hexachloride as well as the Crystal Structures of [(Cl₃PO)WCl₄(H₉C₄? C?C—C₄H₉)] and [(H₅C₆)₄As][WCl₆] The reaction of 2,2-dimethylpropylidynephosphane, (CH₃)₃C? C?P|, with tungsten hexachloride suspended in POCl₃ results, with oxidation of the phosphorus atom, in 2,2,5,5-tetramethylhex-3-yne. This compound reacts with tungsten tetrachloride simultaneously formed to give the alkyne complex [(Cl₃PO)WCl₄(H₉C₄? C?C—C₄H₉)], which is dark green in colour. A small amount of tungsten hexachloride is reduced merely to tungsten pentachloride; after the addition of tetraphenyl arsonium chloride it can be isolated as [(H₅C₆)₄As][WCl₆]. For this compound, a new and very simple synthesis from WCl₆, [(H₅C₆)₄As]Cl and C₂Cl₄ as reducing agent is described. The structure of [(Cl₃PO)WCl₄(H₉C₄? C?C? C₄H₉)] has been determined from X-ray diffraction data (R = 5.8%). The complex crystallizes in the monoclinic space group P2₁/n with: {a = 1510; b = 1517; c = 849 pm; β = 93.1°; Z = 4}. The tungsten atom is sevenfold coordinated by four equatorial chlorine atoms, by the C°C group of the acetylene ligand and by the oxygen atom of the POCl₃ molecule in trans position. The bulky acetylene ligand which is nearly symmetrically bound shifts the chlorine atoms towards the solvated POCl₃ molecule so that no common plane with the tungsten atom is possible. With 130 pm the C°C bond length of the 2,2,5,5-tetramethyl-3-yne ligand corresponds to a C°C double bond. The i.r. spectrum of [(H₅C₆)As][WCl₆] shows two WCl₆ strectching vibrations and therefore proves a reduction of octahedral symmetry. In agreement with the results of a crystal structure determination (space group P4/n; a = 1301; c = 780 pm; Z = 2.7%) the [WCl₆]^?-anion has nearly exact C_4V symmetry with somewhat shorter W? Cl bond lengths parallel to the fourfold axis of rotation.     

Phosphanimin- und Phosphaniminato-Komplexe von Bor. Synthese und Kristallstrukturen von [BF3(Me3SiNPEt3)], [BCl2(NPPh3)]2, [BCl2(NPEt3)]2, [B2Cl3(NPEt3)2]+BCl4− und [B2Cl2(NPiPr3)3]+BCl4−

Phosphaneimine and Phosphoraneiminato Complexes of Boron. Synthesis and Crystal Structures of [BF₃(Me₃SiNPEt₃)], [BCl₂(NPPh₃)]₂, [BCl₂(NPEt₃)]₂, [B₂Cl₃(NPEt₃)₂]⁺BCl₄^?, and [B₂Cl₂(NPⁱPr₃)₃]⁺BCl₄^? The title compounds have been prepared from the corresponding silylated phosphaneimines and boron trifluoride etherate and boron trichloride, respectively. The compounds form white moisture sensitive crystals, which were characterized by ¹¹B-nmr-spectroscopy, IR-spectroscopy and by crystal structure determinations. [BF₃(Me₃SiNPEt₃)] : Space group P2₁/c, Z = 4, R = 0.032 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1361.0, b = 819.56, c = 1422.5 pm, β = 109.86°. The donor acceptor complex forms monomeric molecules with a B? N bond length of 157.8 pm. [BCl₂(NPPh₃)]₂ · 2 CH₂Cl₂ : Space group P2₁/c, Z = 2, R = 0.049 for reflections with I > 2σ(I). Lattice dimensions at ?50°C: a = 1184.6, b = 2086.4, c = 843.0 pm, β = 96.86°. The compound forms centrosymmetric dimeric molecules in which the boron atoms are linked to B₂N₂ four-membered rings with B? N distances of 152.7 pm via μ₂-N bridges of the NPPh₃ groups. [BCl₂(NPEt₃)]₂ : Space group Pbca, Z = 4, R = 0.029 for reflections with I > 2σ(I). Lattice dimensions at ?90°C: a = 1269.5, b = 1138.7, c = 1470.3 pm. The compound has a molecular structure corresponding to the phenyl compound with B? N ring distances of 151.0 pm. [B₂Cl₃(NPEt₃)₂]⁺BCl₄^? : Space group Pbca, Z = 8, R = 0.034 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1309.3, b = 1619.8, c = 2410.7 pm. Within the cations the boron atoms are linked to planar, asymmetrical B₂N₂ four-membered rings with B? N distances of 155.1 and 143.1 pm via the μ₂-N atoms of the NPEt₃ groups. [B₂Cl₂(NPⁱPr₃)₃]⁺BCl₄^? · CH₂Cl₂: Space group Pna2, Z = 4, R = 0.033 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1976.5, b = 860.2, c = 2612.7 pm. Within the cations the boron atoms are linked to planar, asymmetrical B₂N₂ four-membered rings with B? N distances of 153.7 and 150.5 pm via the μ₂-N atoms of two of the NPⁱPr₃ groups. The third NPⁱPr₃ group is terminally connected to the sp²-hybridized boron atom with a B? N distance of 133.5 pm and with a B? N? P bond angle of 165.3°.     

Disulfidoverbrückte Halogenokomplexe von Molybdän(V) Kristallstrukturen von (PPh3Me)2[Cl4Mo(μ-S2)2MoCl4] · 2 CH2Cl2 und (PPh4)2[Br4Mo(μ-S2)2MoBr4] · 3 CH2Br2

Disulfido-Bridged Halo Complexes of Molybdenum (V). Crystal Sructures of (PPh₃Me)₂ [Cl₄Mo (μ-S₂)₂MoCl₄]. 2 CH₂Cl₂ and (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄]. 3CH₂Br₂ . Mo(S₂)Cl₃ is prepared by an improved method; the i.r. spectrum is reported. In dichloro methane solution it reacts with (PPh₃Me)Cl forming the complex (PPh₃Me)₂[Cl₄Mo(μ-S₂)₂MoCl₄] · 2 CH₂Cl₂. The bromo complex (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄] · 3 CH₂Br₂ is obtained by reaction of MoBr₄ with S₇NH and subsequent treatment of the reaction mixture with PPh₄Br in CH₂Br₂ solution. Both complexes are characterized by i.r. spectra and structural analyses by X-ray methods. (PPh₃Me)₂[Cl₄Mo(μ-S₂)₂MoCl₄] · 2 CH₂Cl₂ crystallizes monoclinic in the space group P2₁/c with two formula units per unit cell (5268 observed independent reflexions, R = 4.0%). The lattice dimensions are: a = 1097 pm, b = 1510 pm, c = 1591 pm, β = 104.4°. (PPh₄)₂[Br₄Mo(μ-S₂)₂MoBr₄] · 3 CH₂Br₂ crystallizes triclinic in the space group P&1macr; with two formula units per unit cell and the lattice constants a = 1328 pm, b = 1573 pm, c = 1719 pm, α = 95.8°, β = 96.3°, γ = 74.1°. Both compounds are of ionical structure with PPh₃Me^⊕ and PPh₄^⊕ cations, respectively, and anions [X₄MO(μ-S₂)₂MoX₄]^2? very similar to each other. The molybdenum atoms are bridged by two disulfido ligands and are bonded directly with a bond length of 286 pm. The terminal halogen atoms add up to coordination number nine at the molybdenum.     

(PPh4)2[WO2Cl3]2 · 2 CH2Cl2: Synthese,Schwingungsspektrum und Kristallstruktur

(PPh₄)₂[WO₂Cl₃]₂ · 2 CH₂Cl₂. Synthesis, Vibrational Spectrum, and Crystal Structure Depending on the stoichiometry and the solvent, dichloromethane or 1.2-dichloroethane, WO₂Cl₂ reacts with tetraphenylphosphonium chloride affording (PPh₄)₂[WO₂Cl₄] or (PPh₄)₂[WO₂Cl₃]₂, respectively. Both compounds are easily soluble in dichloromethane, from which they can be crystallized under incorporation of two molecules CH₂Cl₂ per formula unit. The crystalline compounds have been characterized by their IR and Raman spectra. According to the X-ray crystal structure analysis, (PPh₄)₂[WO₂Cl₃]₂ · 2 CH₂Cl₂ crystallizes in the triclinic space group P1 with one formula unit per unit cell (986 independent observed reflexions, R = 0.061). Lattice constants: a = 1100.2, b = 1116.9, c = 1238.4 pm, = 69.40, = 80.46 and = 85.62°. The crystals consist of PPh₄^⊕ ions, centrosymmetric [WO₂Cl₃]₂^2? anions and CH₂Cl₂ molecules. In the anions, the tungsten atoms are linked via two oxo bridges with WO distances of 184 and 252 pm. The distorted octahedral coordination around each tungsten atom is completed by three terminal chloro and one terminal oxo ligand (WO bond length 166 pm), the latter being in trans position to the longer WO bridging bond. (PPh₄)₂[WO₂Cl₄] · 2 CH₂Cl₂ also forms triclinic crystals that are isotypic with (PPh₄)₂[WOCl₅] · 2 CH₂Cl₂ and in which the anions must have orientational disorder.     

Thiobromokomplexe von Arsen und Antimon Darstellung und Kristallstrukturen von (PPh4)2[As2SBr6] · CH2Br2 und (PPh4)2[Sb2SBr6] · CH2Br2

Thiobromo Complexes of Arsenic and Antimony. Preparation and Crystal Structures of (PPh₄)₂[As₂SBr₆] · CH₂Br₂ and (PPh₄)₂[Sb₂SBr₆] · CH₂Br₂ (PPh₄)₂[As₂SBr₆] · CH₂Br₂ is formed by the reaction of As₂S₃, PPh₄I and HI in dibromomethane. It can also be obtained, as well as (PPh₄)₂[Sb₂SBr₆] · CH₂Br₂, from (PPh₄)₂[As₂Br₈] and (PPh₄)₃[Sb₂Br₉], respectively, with bistrimethylsilylsulfide. The crystal structures of the title compounds were determined by X-ray diffraction. They are isotypic with (PPh₄)₂[As₂SCl₆] · C₂H₄Cl₂. In the anions [M₂SBr₆]^2? the M atoms (As or Sb) have a distorted octahedral coordination, the two octahedra share acommon face with one bridging S and two Br atoms; the lone electron pairs occupy the trans positions to the S atom. Crystal data: triclinic, space group P1 , Z = 2; (PPh₄)₂[As₂SBr₆] · CH₂Br₂, a = 119.1, b = 1203.6, c = 2067.5 pm α= 94.89, β = 97.78, γ = 112.20°, 3046 independent observed reflexions, R = 0.083; (PPh₄)₂[Sb₂SBr₆] · CH₂Br₂, a = 1198.9, b = 1224.3, c = 2085.5pm, α = 95.04, β = 98.48, γ = 112.13°C, 2380 reflexions, R = 0.079.     

Komplexe von Osmium (VIII) und Rhenium (VII) mit fünffach koordiniertem Metallatom Kristallstruktur von PPh4[OsO4Cl] · CH2Cl2

Five-coordinated Complexes of Osmium (VIII) and Rhenium (VII). Crystal Structure of PPh₄[OsO₄Cl] · CH₂Cl₂ The five-coordinated anionic complexes [OsO₄Cl]^?, [OsO₄N₃]^?, and [ReO₃Cl₂]^? were isolated as tetraphenylphosphonium salts from reactions of OsO₄ and ReO₃Cl with PPh₄Cl and PPh₄N₃, respectively, in dichloromethane solution. The compounds which are characterized by their i.r. spectra, are thermally sensitive and form crystalline powders with colours ranging from orange to violet. The crystal structure of PPh₄[OsO₄Cl] · CH₂Cl₂ was determined and refined with X-ray diffraction data. (4212 independent, observed reflexions, R = 0.032). It crystallizes in the monoclinic space group P2/b with four formula units per unit cell. The cell dimensions are at ?110°C a = 1754, b = 2184 pm, c = 692 and γ = 106.7°. The structure consists of tetraphenylphosphonium cations and anions [OsO₄Cl]^? with five-coordinated Os atoms in a trigonal bipyramidal geometry with the chlorine ligand in an axial position. The anion can also be regarded as a OsO₄ tetrahedron, monocapped by a chloride ion. Each chloride ion is linked with two CH₂Cl₂ molecules via hydrogen bridges, forming chains in the direction c. The Os? Cl bond length (276 pm) is very long; the average OsO distance (172 pm) corresponds to that in the OsO₄ molecule (170 pm).     

Phosphaniminato-Komplexe von Titan(IV) und Titan(III). Die Kristallstrukturen von [TiCl2(OMe)(NPPh3)]2, [TiBr2(NPPh3)]2 · 3 C7H8 sowie von [Ph3PNH2]Br · CH2Cl2

Phosphorane Iminato Complexes of Titanium(IV) and Titanium(III). The Crystal Structures of [TiCl₂(OMe)(NPPh₃)]₂, [TiBr₂(NPPh₃)]₂ · 3C₇H₈, and [Ph₃PNH₂]Br · CH₂Cl₂ TiCl₃(NPPh₃) reacts with a solution of methyllithium in diethyl ether in the presence of lithiummethylate forming yellow [TiCl₂(OMe)(NPPh₃)]₂. On reaction with benzyl magnesium bromide TiCl₃(NPPh₃) in diethyl ether is converted into green [TiBr₂(NPPh₃)]₂ under reduction and ligand exchange. [TiBr₂(NPPh₃)]₂ crystallizes from toluene with three molecules C₇H₈. [Ph₃PNH₂]Br · CH₂Cl₂ originates as a side product of this reaction. The products are characterized by their i.r. spectra and by crystal structure analyses. [TiCl₂(OMe)(NPPh₃)]₂ . Space group P1 , Z = 2, structure solution with 2909 independent reflections, R = 0.063. Lattice dimensions at 20°C: a = 1005.1, b = 1044.5, c = 1068.6 pm, α = 66.98°, β = 89.35°, γ = 80.24°. The compound forms centrosymmetric dimeric molecules with μ₂-OMe bridges and five-fold coordinated titanium atoms. The (NPPh₃^?) ligand is terminally connected with a Ti = N distance of 174.8 pm and with a TiNP bond angle of 165.3°. [TiBr₂(NPPh₃)]₂ · 3 C₇H₈ . Space group P1 , Z = 2, structure solution with 5548 independent reflections, R = 0.053. Lattice dimensions at ?70°C: a = 983.3, b = 1162.7, c = 1376.5 pm, α = 100.53°, β = 110.30°, γ = 105.24°. The compound forms centrosymmetric dimeric molecules with μ₂-NPPh₃ bridges and tetrahedral coordination at the titanium atoms. With 195.9 pm the Ti–N bonds correspond with single bonds. The Ti …? Ti distance of 260.0 pm is exceptionally short. [Ph₃PNH₂]Br · CH₂Cl₂ . Space group P1 , Z = 1, structure solution with 3091 independent reflections, R = 0.049. Lattice dimensions at 20°C: a = 909.4, b = 1004.4, c = 1158.5 pm, α = 108.09°, β = 94.67°, γ = 91.92°. The bromide ions are bonded to a one-dimensional infinite network via hydrogen bridge bonds of the cation and of the dichloromethane.