(PPh3Me)2[{MoCl4(NO)}2 (μ-S2N2)]; Synthese,IR-Spektrum und Kristallstruktur

(PPh₃Me)₂[{MoCl₄(NO)}₂(μ-S₂ N₂)]; Synthesis, I.R. Spectrum, and Crystal Structure The title compound is prepared by the reaction of (PPh₃Me)₂[MoCl₃(NO)₂]₂ with trithiazyl chloride in CH₂Cl₂ solution. It forms yellow, only slightly moisture sensitive crystals, which are characterized by their IR spectrum as well as by an X-ray structure determination. (PPh₃Me)₂[{MoCl₄(NO)}₂ (μ-S₂N₂)] crystallizes triclinic in the space group P1 with one formula unit in the unit cell (5952 independent, observed reflexions, R = 0.045). The lattice dimensions are at 20°C: a = 1021, b = 1143, c = 1243, pm; α = 64,15°, β = 68.24°, γ = 80.85°. The compound consists of PPh₃Me⊕ cations and anions [{MoCl₄(NO)}₂(μ-S₂N₂)]²?, in which the molybdenum atoms are bridged by the N-atoms of the planar S₂N₂ ring. In the trans-positions of these N-atoms the linear nitrosyl groups are coordinated via Mo ? N ? O .     

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.     

Komplexe des Rheniums mit planarer ReN2S2-Fünfringstruktur Synthesen und Kristallstrukturen von AsPh4[ReCl4(N2S2)] und PPh4[ReBr4(N2S2)]

Complexes of Rhenium with Planar ReN₂S₂ Rings. Syntheses and Crystal Structures of AsPh₄[ReCl₄(N₂S₂)] and PPh₄[ReBr₄(N₂S₂)] The complex [ReCl₄(N₂S₂)]^? can be obtained as PPh₄^⊕ or AsPh₄^⊕ salt by the action of S(NSiMe₃)₂ and of diphenylacetylene, respectively, on the chlorothionitrene complex [ReCl₄(NSCl)₂]^?. Another method of synthesis is the reaction of [ReCl₃(NSCl)₂(POCl₃)] with SbPh₃. [ReBr₃(N₂S₂)]₂ is obtained from excess Me₃SiBr and [ReCl₃(NSCl)₂(POCl₃)]. The anionic complex [ReBr₄(N₂S₂)]^? forms from either [ReCl₄(NSCl)₂]^? or [ReCl₄(N₂S₂)]^? with Me₃SiBr. All compounds are black, diamagnetic, and sensitive to moisture; the PPh₄^⊕ and AsPh₄^⊕ salts are soluble in CH₂Cl₂ and CH₂Br₂. The IR spectra are reported. The crystal structures of AsPh,₄[ReCl₄(N₂S₂)] and PPh₄[ReBr₄(N₂S₂)] were determined by X-ray diffraction. AsPh₄[ReCl₄(N₂S₂)]: space group P2/n, Z = 2, a = 1244.5, b = 1429.3, c = 791.1 pm, γ = 96.89° (1715 observed reflexions, R = 0.082). PPh₄[ReBr₄[ReBr₄(N₂S₂)]: space group P2₁/n, Z = 4, a = 961.7, b = 1397.4, c = 2205.7 pm, β = 102.10° (1787 observed reflexions, R = 0.073). In both compounds the [ReX₄(N₂S₂)]? anions have the same type of structure, the Re atoms forming part of planar ReN₂S₂ rings; the bond lengths are ReN 177 pm, NS 152 pm, and SS 259 for the chloro compound and ReN 184 pm, NS 153 pm, and SS 264 pm for the bromo compound. In AsPh₄[ReCl₄(N₂S₂)] the cations are stacked to form columns in the c-direction; in PPh₄[ReBr₄(N₂S₂)], there is considerable distortion form this packing principle.     

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.     

[PPh3Cl]⊕[ReCl4(N2S2)]⊖ Synthese,IR-Spektrum und Kristallstruktur

[PPh₃Cl]^⊕[ReCl₄(N₂S₂)]^?; Synthese, IR-Spektrum und Kristall Strukture The title compound is prepared by the reaction of [ReCl₃(NSCl)₂(POCl₃)] with triphenylphosphane; it formes black crystals. The crystal structure determination was solved with X-ray methods (2861 observed independent reflexions, R = 0.038). The compound crystallizes monoclinic in the space group P2₁/n with four formula units per unit cell. The structure consists of [PPh₃Cl]^⊕ cations and [ReCl₄(N₂S₂)]^? anions, in which the rhenium atom is surrounded octahedrally by four chlorine ligands and the N atoms of a ReN₂S₂-five-membered ring in cis-position (symmetry C_2v). The Re? N bond lengths (181 pm) and the NS bond lengths (152 pm) are in the range of double bonds; the S? S distance is very long (253 pm). The i.r. spectrum is reported.     

Diiodacetylenkomplexe von Wolfram(IV). Die Kristallstruktur von PPh4[WCl5(C2l2)] · 0,5 CH2Cl2

Diiodoacetylene Complexes of Tungsten(IV). Crystal Structure of PPh₄[WCl₅(C₂I₂)] · 0.5 CH₂Cl₂ Tungsten hexachloride and diiodoacetylene react in CCl₄ solution forming [WCl₄(I? C?C? I)]₂ which has a dimer structure with chloro bridges. In CH₂Cl₂, it reacts with PPh₄Cl yielding PPh₄[WCl₅(I? C?C? I)] · 0.5 CH₂Cl₂. In both compounds the C₂I₂ ligands attain a marked increase in thermal stability by their side-one coordination to the tungsten atoms. The crystal structure of the PPh₄^⊕ salt was determined with X-ray diffraction data (3879 observed reflexions, R = 0.050). PPh₄[WCl₅(C₂I₂)] · 0.5 CH₂Cl₂ crystallizes in the space group P2₁/n with 8 formula units per unit cell. The lattice constants are a = 1723.0, b = 1681.2, c = 2214.6 pm and β = 94.38°. There are two crystallographically independent [WCl₅(C₂I₂)]^? ions which differ only slightly from one another. The C₂I₂ ligand has a staggered arrangement relative to the W? Cl groups, with C? C bond lengths of 127 pm. The infrared spectra are discussed.     

Thiokomplexe des Molybdäns Kristallstruktur eines Mischkristalls (PPh3Me)2[Mo2Br6(NO)4]/(PPh3Me)2[Mo2Br6S2(NO)2]

Thiocomplexes of Molybdenum. Crystal Structure of a Mixed Single Crystal (PPh₃Me)₂[Mo₂Br₆(NO)₄]/(PPh₃Me)₂[Mo₂Br₆S₂(NO)₂] The reactions of (PPh₄)₂MoS₄ with MoBr₄ and MoBr₂(NO)₂ resp. lead to the binuclear complexes (PPh₄)₂[S₂MoS₂MoBr₃(SMe₂)] and (PPh₄)[S₂MoS₂MoBr₂(NO)₂], in which the molybdenum atoms are linked by sulfido bridges. The preparation of (PPh₃Me)₂S₆ and (AsPh₄)₂S₇ from Na₂S₄ and PPh₃MeBr, and AsPh₄Cl, respectively, in ethanol solution is described. Disulfido briges are a feature of (AsPh₄)₂[Mo₂Br₆(S₂)₂(SMe₂)₂], which is obtained from MoBr₄(SMe₂)₂ and (AsPh₄)₂S₇. Mixed single crystals containing 2/3 (PPh₃Me)₂[Mo₂Br₆(NO)₄] and 1/3 (PPh₃Me)₂[Mo₂Br₆S₂(NO)₂] are formed in the reaction of MoBr₂(NO)₂ with (PPh₃Me)₂S₆, as shown by X-ray single crystal structure determination. The compound crystallizes monoclinic in the space group C2/c (Internat. Tab. Nr. 15) with four formula units per unit cell (2351 independent observed reflexions, R_w = 0.037). The cell parameters are a = 1603 pm, b = 1549 pm, c = 1863 pm; β = 92.2°. The complexes consist of PPh₃Me^⊕ cations and the dimeric anions [Mo₂Br₆(NO)₄]^2? and [Mo₂Br₆S₂(NO)₂]^2? which occur in the ratio 2:1. In these the molybdenum atoms are connected via MoBr₂Mo bridges of slightly different lengths (Mo? Br 265 pm and 267 pm) forming a controsymmetric double octahedron. All molybdenum atoms have two terminal bromo ligands with Mo? Br bond lengths of 258 pm and 260 pm; in the [Mo₂Br₆(NO)₄]^2? ion each molybdenum has two covalently bonded nitrosyl groups on cis-position with Mo? N bond lengths of 183 pm. In the [Mo₂Br₆S₂(NO)₂]^2? ion one of the two nitrosyl groups at each metal atom is substituted by a terminal sulfido ligand with a Mo? S bond length of 240 pm. The i.r. spectra are reported.     

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.     

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°.     

[ReCl2(NS)(NSCl)(Pyridin)2], ein Thionitrosyl-chlorthio-nitrenkomplex des Rheniums

[ReCl₂(NS)(NSCl)(Pyridine)₂], a Thionitrosyl-chlorothionitrene Complex of Rhenium The title compound was obtained by the reaction of pyridine with either [ReCl₃(NSCl)₂POCl₃] or [ReCl₃(NSCl)₂]₂ · (μ-N₂S₂) under the reducing action of dichloromethane. It is slightly soluble in CH₂Cl₂, from which it can be obtained in form of black crystals. The IR spectrum is reported. The crystal structure of [ReCl₂(NS)(NSCl)(Pyridine)₂] was determined by X-ray diffraction (R = 0.027 for 2105 observed reflexions). Crystal data: a = 1551.6, b = 694.9, c = 1513.2 pm, β = 96.50°, space group P2₁/c, Z = 4. In the monomer molecules, each rhenium atom has a distorted octahedral coordination of two cis-chlorine atoms, two cis-nitrogen atoms of the pyridine ligands and two cis-nitrogen atoms of the thionitrosyl and chloro thionitrene ligands. One of the pyridine groups is in trans position to the nearly linear thionitrosyl group (angle ReNS 176°) with distances ReN of 177 pm and NS of 152 pm. However, in the trans position of the chlorothionitrene group (angle ReNS 159°, distances ReN 189 pm, NS 149 pm) a chlorine atom is found.     

Synthese und Kristallstruktur von Tetraphenylphosphonium-Aquabis(tetrasulfido)thionitrosyl-Osmat,PPh4[Os(NS)(S4)2(H2O)]

Synthesis and Crystal Structure of Tetraphenylphosphonium Aqua-bis(tetrasulfido)thionitrosyl Osmate, PPh₄[Os(NS)(S₄)₂(H₂O)] PPh₄[Os(NS)(S₄)₂(H₂O)] has been prepared as redbrown crystals by reacting PPh₄[OsNCl₄] with a solution of excess disodium tetrasulfide in dimethylformamide/H₂O and characterized by IR spectroscopy and by a crystal structure determination. Space group P2₁/n, Z = 4, structure solution with 4162 independent reflections, R = 0.059 for reflections with I > 2σ(I). Lattice dimensions at ?40°C: a = 1138.9(5), b = 1301.4(4), c = 2092.7(7) pm, β = 104.74(3)º. Os? N, Os? O, and Os? S distances are 175.2(12), 219.8(12), and 237.5(4)?239.1(4) pm, respectively. The Os?N?S moiety is approximately linear, with an OsNS angle of 171.2(7)º.     

Synthese und Struktur des μ-Sulfido-μ-disulfido-octabromodiwolframat(V)-Ions [W2S3Br8]2−

Synthesis and Structure of μ-Sulfido-μ-disulfido-octabromoditungstate(V), [W₂S₃Br₈]^?2 Tungsten hexabromide reacts with H₂S in dichloromethane yielding a brown product which, by addition of tetraphenylphosphonium bromide in CH₂Cl₂, is converted to brown, crystalline (PPh₄)₂[Br₄W(μ-S)(μ-S₂)WBr₄] · CH₂Cl₂ · CH₂S. Its IR spectrum is reported, its crystal structure was determined by X-ray diffraction (2330 reflexions, R = 0.097). Crystal data: orthorhombic, Pnma, a = 1 766.5, b = 2 412.7, c = 1 416.3 pm, Z = 4. In the diamagnetic [W₂S₃Br₈]^2? ions the two W atoms are linked via a sulfido and a disulfido bridge and by a W? W bond.     

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.     

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°.     

(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.     

Phosphanimin- und Phosphaniminato-Komplexe von Eisen. Die Kristallstrukturen von [FeCl3(Me3SiNPEt3)], [FeCl2(Me3SiNPEt3)]2, [FeCl2(NPEt3)]2 und [Fe(O2C?CH3)2(NPEt3)]2

Phosphanimine and Phosphoraneiminato Complexes of Iron. The Crystal Structures of [FeCl₃(Me₃SiNPEt₃)], [FeCl₂(Me₃SiNPEt₃)]₂, [FeCl₂(NPEt₃)]₂, and [Fe(O₂C? CH₃)₂(NPEt₃)]₂ The phosphanimine complexes [FeCl₃(Me₃SiNPEt₃)] (red-orange) and [FeCl₂(Me₃SiNPEt₃)]₂ (colourless) have been prepared by reactions of Me₃SiNPEt₃ with FeCl₃ and FeCl₂, respectively, in CH₂Cl₂ suspensions. Thermal decomposition of these donor-acceptor complexes in boiling toluene leads to the phosphoraneiminato complex [FeCl₂(NPEt₃)]₂ (black), whereas [Fe(O₂C? CH₃)₂(NPEt₃)]₂ (brown) is formed from iron(II) acetate and Me₃SiNPEt₃ in boiling acetonitrile. The complexes are characterized by IR spectroscopy and by crystal structure determinations. [FeCl₃(Me₃SiNPEt₃)] (1) : Space group P2₁/c, Z = 8, structure determination with 4 673 unique reflections, R = 0.033. Lattice dimensions at ?15°C: a = 1 607.8, b = 1 602.0, c = 1 417.2 pm, β = 106.56°. 1 forms monomeric molecules with tetrahedrally coordinated iron atoms. Bond lengths in average: Fe? N = 196.9 pm, Fe? Cl = 219.7 pm. [FeCl₂(Me₃SiNPEt₃)]₂ (2) : Space group P2₁/c, Z = 4, structure determination with 4 992 unique reflections, R = 0.048. Lattice dimensions at 20°C: a = 1 457.9, b = 1 685.4, c = 1 507.3 pm, β = 116.74°. 2 forms dimeric molecules, which are associated by chloro bridges. The iron atoms are tetrahedrally coordinated with trans positions of the phosphanimine ligands. Both lengths in average: Fe? N = 202.2 pm, Fe? Cl_terminal = 224.7 pm, Fe? Cl bridge = 241.0 pm. [FeCl₂(NPEt₃)]2 (3): Space group P2₁/n, Z = 2, structure determination with 2763 unique reflections, R = 0.039. Lattice dimensions at ?70°C: a = 799.1, b = 1009.0, c = 1441.9 pm, β = 93.45°. 3 forms centrosymmetric dimeric molecules, in which the tetrahedrally coordinated iron atoms are associated by the nitrogen atoms of the phosphoraneiminato ligands. Bond lengths in average: Fe? N = 191.4 pm, Fe? Cl = 222.7 pm. [Fe(O₂C? CH₃)₂(NPEt₃]2 (4): Space group P2₁/n, Z = 2, structure determination with 3005 observed unique reflections, R = 0.034. Lattice dimensions at -65°C: a = 886.4, b = 1444.6 pm, β = 90.60°. 4 forms centrosymmetric dimeric molecules, in which the octahedrally coordinated iron atoms are associated by the nitrogen atoms of the phosphoraneiminato ligands with bond lengths Fe? N of 191.9 and 195.0 pm. The acetate groups are coordinated in a chelating fashion.     

New ruthenium(III) complexes containing tetradentate Schiff bases and their antibacterial activity

Ruthenium(III) complexes, [RuX(EPh₃)(LL)] (X = Cl, Br; E = P, As; LL-acactet, dbm-tet, dbm-o-ph), have been synthesised by reacting [RuCl₃(PPh₃)₃], [RuCl₃(AsPh₃)₃], [RuBr₃(AsPh₃)₃] or [RuBr₃(PPh₃)₂(MeOH)] with tetradentate Schiff bases such as bis(acetylacetone)tetramethylenediimine (H₂acactet), bis(dibenzoylmethane)tetramethylenediimine (H₂dbmtet) and bis(dibenzoylmethane)-o-phenylenediimine (H₂dbm-o-ph). All the complexes have been characterised by elemental analysis, i.r., electronic spectra, e.p.r., magnetic moment and cyclic voltammetric data and an octahedral structure has been tentatively proposed. These new complexes have been tested for their antibacterial activities.     

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).     

Synthese und Kristallstruktur von (PPh4)2[Mo2Cl10]

Synthesis and Crystal Structure of (PPh₄)₂[Mo₂Cl₁₀] The title compound is obtained in the reaction of [MoCl₄(Ph? C?C? Ph)]₂ with tetraphenylphosphonium chloride in dichloro methane, forming brown crystals. It is characterized by the i.r. spectrum and a crystal structure analysis by the aid of X-ray diffraction data. The complex crystallizes triclinic in the space group P1 with one formula unit per unit cell. The cell dimensions are a = 1122 pm, b = 1137 pm, c = 1283 pm; α = 63.4°, β = 69.1°, γ = 86.5°. The crystal structure determination (2959 observed, independent reflexions, R = 4.5%) shows the constants of the unit cell to consist of on centrosymmetric anion, two cations and one disordered molecule of dichloro methane. The distance Mo? Mo in the anion is 380 pm, which excludes direct magnetic interaction between the molybdenum atoms.     

Tridentate Thiolate Ligands: Application to the Synthesis of the Site-Differentiated [4Fe-4S] Cluster having a Hydrosulfide Ligand at the Unique Iron Center

We have designed new trithiols Temp(SH)₃ and Tefp(SH)₃ that can be synthesized conveniently in short steps and are useful for preparation of crystalline [3:1] site-differentiated [4Fe-4S] clusters suitable for X-ray structural analysis. The ethanethiolate clusters (PPh₄)₂[Fe₄S₄(SEt)(TempS₃)] ( 4a ) and (PPh₄)₂[Fe₄S₄(SEt)(TefpS₃)] ( 4b ) were prepared as precursors, and the unique iron sites were then selectively substituted. Upon reaction with H₂S, (PPh₄)₂[Fe₄S₄(SH)(TempS₃)] ( 6a ) and (PPh₄)₂[Fe₄S₄(SH)(TefpS₃)] ( 6b ), which model the [4Fe-4S] cluster in the β subunit of (R)-2-hydroxyisocaproyl-CoA dehydratase, were synthesized. Clusters 6a and 6b were further converted to the sulfido-bridged double cubanes (PPh₄)₄[{Fe₄S₄(TempS₃)}₂(μ²-S)] ( 6b ) and (PPh₄)₄[{Fe₄S₄(TefpS₃)}₂(μ²-S)] ( 7b ), respectively, via intermolecular condensation with the release of H₂S. Conversely, addition of H₂S to 7a , 7b afforded the hydrosulfide clusters 6a , 6b . The molecular structures of the clusters reported herein were elucidated by X-ray crystallographic analysis. Their redox properties were investigated by cyclic voltammetry.