Dichlorphosphato-Komplexe von Zinn,Titan und Molybdän Die Kristallstruktur von (AsPh4)2[MoOCl3(PO2Cl2)]2

Dichlorophosphato Complexes of Tin, Titanium, and Molybdenum. Crystal Structure of (AsPh₄)₂[MoOCl₃(PO₂Cl₂)]₂ The dichlorophosphate complexes (AsPh₄)₂[SnCl₄(PO₂Cl₂)]₂ ( I ), (AsPh₄)₂[TiCl₄(PO₂Cl₂)]₂ ( II ) and (AsPh₄)₂[MoOCl₃(PO₂Cl₂)]₂ ( III ) are prepared by the reactions of SnCl₄, TiCl₄, and MoCl₅, respectively, with AsPh₄[PO₂Cl₂] in dichlormethan solutions. According to their i.r. spectra, the complex anions form dimeric species via the oxygen atoms of the dichlorophosphate groups; the ¹¹⁹Sn Mössbauer spectra of I are reported in addition. The crystal structure of III is solved by X-ray diffraction methods and refined to R = 4.3%. (AsPh₄)₂[MoOCl₃(PO₂Cl₂)]₂ crystallizes in the triclinic space group P1 with one formula unit pro unit cell. The structure consists of tetraphenylarsonium cations and centrosymmetric anions [MoOCl₃(PO₂Cl₂)]₂^2?. The molybdenum atoms of the anions are linked via the O atoms of the dichlorophosphate groups forming nonplanar Mo₂O₄P₂ eight-membered rings.     

Dithiolylium‐Chlorooxomolybdate(V): Synthese und Kristallstruktur von (C3Cl3S2)[MoOCl4] und (C3Cl3S2)[Mo2O2Cl7]

Dithiolylium Chlorooxomolybdates(V): Synthesis and Crystal Structure of (C₃Cl₃S₂)[MoOCl₄] and (C₃Cl₃S₂)[Mo₂O₂Cl₇] The reaction of 3, 4, 5‐Trichlor‐1, 2‐dithiolylium chloride with MoOCl₃ in dichlormethane under solvothermal conditions at 65 °C simultaneously yields the green tetrachlorooxomolybdate(V) (C₃Cl₃S₂)[MoOCl₄] and the yellow‐brown heptachlorodioxodimolybdate(V) (C₃Cl₃S₂)[Mo₂O₂Cl₇]. The crystal structures of both compounds contain nearly planar (C₃Cl₃S₂)⁺ ions with a S—S bond length of 203 pm. The discrete [MoOCl₄]^— ion in the structure of (C₃Cl₃S₂)[MoOCl₄] has the shape of a square pyramid with the oxygen atom at the apex. The molybdenum atom is displaced by 58 pm from the basal plane towards the oxygen atom. The [Mo₂O₂Cl₇]^— ion in the structure of (C₃Cl₃S₂)[Mo₂O₂Cl₇] has the form of a face‐sharing double octahedron. It is formally composed of a [MoOCl₄]^— ion and a MoOCl₃ molecule connected by one symmetrical and two unsymmetrical chloro bridges. The molybdenum atoms placed in the centers of such connected octahedra are 357 pm apart, indicating no Mo—Mo bond.     

Nitrosylkomplexe des Molybdän(+II) Die Kristallstrukturen von [Mo(NO)Cl3 · POCl3]2 und von [AsPh4]2[Mo(NO)Cl5] · 2 CH2Cl2

Nitrosyl Complexes of Molybdenum (+II). Crystal Structures of [Mo(NO)Cl₃ · POCl₃]₂ and [AsPh₄]₂[Mo(NO)Cl₅] · 2 CH₂Cl₂ Solutions of MoCl₅ in POCl₃ react with NOCl forming the nitrosyl compound Mo(NO)Cl₃ · 2POCl₃ ( I ), which in CH₂Cl₂ cleaves off one solvate molecule, yielding the dimeric complex [Mo(NO)Cl₃ · POCl₃]₂ ( II ). Reaction with AsPh₄Cl in dichloro methane leads to the nitrosyl complexes AsPh₄[Mo(NO)Cl₄] · CH₂Cl₂ ( III ) and [AsPh₄]₂[Mo(NO)Cl₅] · 2CH₂Cl₂ ( IV ), respectively. The i.r. spectra are recorded and assigned. [Mo(NO)Cl₃ · POCl₃]₂ crystallizes monoclinic in the space group P2₁/c with two dimeric units per unit cell. The crystal structure was determined by X-ray diffraction methods (R = 0.040; 1391 observed, independent reflexions). Complex II is linked by chlorine bridges, forming a dimeric, centrosymmetric molecule of symmetry C_i. The N? O bond of the nitrosyl ligand is extremely short (108 pm), the Mo? N bond (181 pm) corresponds to a double bond. In trans position to the NO ligand, which is coordinated in linear array, there is the O atom of the solvate molecule POCl₃. [AsPh₄]₂[Mo(NO)Cl₅] · 2 CH₂Cl₂ crystallizes triclinic in the space group P1 with two units per unit cell (R = 0.039; 1967 observed, independent reflexions). The molybdenum atom is coordinated octahedrally by five Cl ligands and a nitrosyl group, as well coordinated in linear array (Mo? N? O 174°). The nitrosyl ligand exerts a significant trans-effect (r Mo? Cl_(trans) = 247 pm, r MoCl_4(eq)(average) = 239 pm).     

Die Reaktion von Molybdänpentachlorid mit Trichlornitromethan; die Kristallstruktur von [MoOCl3 · POCl3]2

Reaction of Molybdenum Pentachloride with Trichloronitromethane. Crystal Structure of [MoOCl₃ · POCl₃]₂ An improved method for the preparation of MoO₂Cl₂ by the reaction of MoCl₅ with CCl₃NO₂ is reported. In the presence of the solvens POCl₃, molybdenum pentachloride reacts with trichloronitromethane forming the oxonitrosyl complex Mo(NO)OCl₃ · POCl₃. In CH₂Cl₂ solution this complex is decomposed forming [MoOCl₃ · POCl₃]₂. The crystal structure was solved by X-ray methods. [MoOCl₃ · POCl₃]₂ crystallizes monoclinic in the space group P2₁/c with two dimers in the unit cell (R = 0.07, 2327 independent reflexions). The complex dimerizes by symmetric chloro bridges; the oxoligand is in terminal position. The MoO bond length of 163 pm corresponds with a Mo?O triple bond. The POCl₃ molecule is coordinated in position trans to the oxoligand. The IR spectra are reported and assigned.     

Nitrosyl-tetrachloro-dichlorphosphato-molybdat(+II); Darstellung,IR-Spektrum und Kristallstruktur von (AsPh4)2[Mo(NO)Cl4(O2PCl2)]

Nitrosyl-tetrachloro-dichlorophosphate-molybdate(+II); Preparation, I.R. Spectrum and Crystal Structure of (AsPh₄)₂[Mo(NO)Cl₄(O₂PCl₂)] The title compound is prepared by the reaction of AsPh₄[Mo(NO)Cl₄] with AsPh₄? [PO₂Cl₂] in dichloromethane solution. It forms orange crystals which are only little sensitive to moisture. The complex crystallizes triclinic in the space group P1 with two formula units in the unit cell. The structure was solved by X-ray diffraction methods (2498 observed, independent reflexions, R = 5.4%). The compound consists of AsPh₄^⊕ cations and [Mo(NO)Cl₄(PO₂Cl₂)]^2? anions. The NO ligand is coordinated in linear array \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop {{\rm MO}}\limits^ \ominus = \mathop {\rm N}\limits^ \oplus = {\rm O}(177^{\circ}) $\end{document}. The dichlorophosphate group is coordinated in trans position to the NO ligand with one of its oxygen atoms. The Mo?N bonding of the NO ligand causes the bond angle NMoCl of 93.2° in average. The IR spectrum is recorded and assigned.     

[Cl3PNPCl3][MoNCl4], eine Verbindung mit strangartig assoziierten Anionen

[Cl₃PNPCl₃][MoNCl₄], a Compound having Columns of Stacked Anions The title compound is formed by the reaction of [Cl₃PNPCl₃]Cl with MoNCl₃ in CH₂Cl₂ and subsequent precipitation with CCl₄ in from of orange-red crystals. According to the ³¹P-NMR spectrum, the compound exists as its isomer phosphaneiminate [Cl₅Mo(NPCl₂NPCl₃)] in CD₂Cl₂/CH₃CN solution. The crystal structure of [Cl₃PNPCl₃][MoNCl₄] is isotypic with that of [Cl₃PNPCl₃][MoOCl₄] and shows the same kind of two-dimensional disorder. X-ray diffraction patterns show planes of diffuse scattering as well as Bragg reflexions. The latter correspond to an averaged structure with a = 1590.0, b = 1141.6, c = 418.0 pm, space group Pba2, Z = 2. In the averaged structure (606 reflexions, R = 0.071) the atom sites have fractional occupation. The real structure consists of square-pyramidal [MoNCl₄]^? ions stacked to form columns with alternating MoN distances of 175 and 243 pm. The packing of the columns is disordered in that the [MoNCl₄]^? pyramids point either in the +c or ?c direction. The [Cl₃PNPCl₃]⁺ ions are stacked in the c direction and show two types of disorder, namely a displacement parallel to c and a rotation by 120° about the P? P axis.     

95Mo NMR spectral studies on seven-coordinate molybdenum(II) isocyanide complexes

The ⁹⁵Mo NMR spectra of a series of seven-coordinate molybdenum(II) isocyanide complexes of the types [Mo(CNR)_7-nL_n](PF₆)₂ (R = CH₃, CHMe₂, CMe₃, C₆H₁₁, CH₂Ph; L = py, bpy, Me₂bpy, phen, dppe, P-n-Bu₃; n = 0,1,2) [Mo(CNC-Me₃)₆X]PF₆ (X = Cl, Br, I) and [{Mo(CNCMe₃)₄(NN)}₂(μ-CN)](PF₆)₃ (NN = bpy, Me₂bpy, phen) have been studied. The ⁹⁵Mo chemical shift range for this group of complexes is about 1100 ppm. An increase in the size of the R group attached to the isocyanide ligand generally tends to shield the ⁹⁵Mo nucleus. Replacement of the isocyanide ligand with a phosphorus ligand also increases the shielding, whereas the replacement of isocyanide with a heterocyclic nitrogen donor leads to deshielding by 800–900 ppm. This group of complexes shows a normal halogen dependence, i.e. replacement of Cl^? by Br^? and I^? increases the shielding of the ⁹⁵Mo nucleus. The cyano-bridged cations [{Mo(CNCMe₃)₄(NN)}₂(μ-CN)]³⁺ (NN = bpy, Me₂bpy, or phen) show two ⁹⁵Mo NMR signals, one for the molybdenum coordinated to the carbon of the bridging CN and one for the N-coordinated molybdenum. Comparison of the chemical shifts and linewidths of the cyano-bridged species with those of the corresponding mononuclear molybdenum(II) complexes [Mo(CNCMe₃)₅(NN)](PF₆)₂ leads to the assignment of the more deshielded signal to the N-coordinated molybdenum. The ¹⁴N and ³¹P NMR spectra for these complexes have also been measured, as have the ¹³C NMR spectra of the pairs of complexes [Mo(CNCMe₃)₅(NN)](PF₆)₂ and [{Mo(CNCMe₃)₄(NN)}₂(μ-CN)](PF₆)₃ (NN = bpy or phen). The ¹⁸³W NMR spectra for [W(CNR)₅(bpy)](PF₆)₂ (R = CMe₃ and CH₂Ph), show that the δ(¹⁸³W)/δ(⁹⁵Mo) chemical shift ratios for isocyanide complexes are different from the ratio found for M⁰ and M^VI.     

AsPh4[W2Cl4(N3S2)3] · CCl4; Synthese und Kristallstruktur

AsPh₄[W₂Cl₄(N₃S₂)₃] · CCl₄; Synthesis and Crystal Structure The title compound was obtained in form of black crystals along with other products by the reaction of H₂S and AsPh₄[WCl₄(N₃S₂)] in dichloromethane and subsequent addition of CCl₄. Its crystal structure was determined by X-ray diffraction (3036 observed reflexions, R = 0.051). Crystal data: triclinic, space group P¯1, Z = 2, a = 1369, b = 1398, c = 1441 pm, α = 64.8, β = 68.02 and γ = 58.1°. The compound consists of AsPh₄^⊕ ions, CCl₄ molecules and [W₂Cl₄(N₃S₂)₃]^? ions. In the latter, one tungsten atom is member of one planar WN₃S₂ ring while the second tungsten atom belongs to two such rings forming a nearly planar S₂N₃WN₃S₂ unit. Two nitrogen atoms of this unit are linked to the other tungsten atom forming a WN₂W ring. Two chloro ligands at each tungsten atom complete the coordination sphere to coordination numbers of six.     

The influence of the nature of the ligand,L, on the electrochemical behaviour of dinitrosyl molybdenum complexes,Mo(NO)2L2Cl2, in aprotic media

Electrochemical investigations of the reduction of dicationic, monocationic and neutral dinitrosyl molybdenum complexes in nitromethane and acetonitrile are reported. All the compounds with the general formulae: [Mo(NO)₂L₂L′₂]²⁺, [Mo(NO)₂L₂L′Cl]⁺ and Mo(NO)₂L₂Cl₂ (L = CH₃CN, CH₂CHCN, C₆H₅CN, C₅H₅N, P(C₆H₅)₃, L₂ = 2,2′-bipyridine, L′ = CH₃CN and L′₂ = 2,2′-bipyridine) are reducible by one electron to yield 19-electron complexes. The dicationic complexes undergo a reversible one-electron transfer. For the mono- and dichlorocomplexes, the one-electron transfer induces the facile exchange of the chloroligand in the 19-electron complexes except for L₂ = 2,2′-bipyridine. However, the exchange of the chloroligand is followed by the fast anation by Cl^? of the remaining 18-electron chlorocomplexes to afford [Mo(NO)₂Cl₃L]^? and [Mo(NO)₂Cl₄]^2? which are reducible at higher negative potentials than dichloro- and monochlorocomplexes. The multiple electrochemical step system is not catalytic, but of the electroactivation type.     

(AsPh4)2[(μ-N2S2) (VCI5)2] Synthese,IR-Spektrum und Kristallstruktur

(AsPh₄)₂[(μ-N₂S₂)(VCl₅)₂]. Synthesis, I.R. Spectrum, and Crystal Structure From the reaction of VCl₄ and S₃N₂Cl₂ in CCl₄ solution a solid, black product mixture is obtained. From this, the title compound can be extracted by reaction with AsPh₄Cl in CH₂Cl₂ solution. It can also be synthesized from AsPh₄VCl₅ and S₃N₃Cl₃ in CH₂Cl₂ solution. The i.r. spectra of (AsPh₄)₂[(μ-N₂S₂)(VCl₅)₂] (black crystal plates) and AsPh₄VCl₅ (brown needles) are reported. The crystal structure of (AsPh₄)₂[(μ-N₂S₂)(VCl₅)₂] was determined by X-ray diffraction. It crystallizes in the monoclinic space group P2₁/c with two formula units per unit cell. The lattice constants are a = 1113.9, b = 1712.8, c = 1508.8 pm, β = 106.68°. The centrosymmetric [(μ-N₂S₂)(VCl₅)₂]^2? ion consists of two quadratic-pyramidal VCl₅ units which are linked via the N atoms of a N₂S₂ ring. The N₂S₂ ring shows positional disorder in two different orientations in the crystal. The AsPh₄⊕ ions form (AsPh₄⊕)₂ pairs via inversion centers, each pair is surrounded by eight anions.     

Kinetics and products of propargyl (C3H3) radical self‐reactions and propargyl‐methyl cross‐combination reactions

Propargyl (HCC CH₂) and methyl radicals were produced through the 193‐nm excimer laser photolysis of mixtures of C₃H₃Cl/He and CH₃N₂CH₃/He, respectively. Gas chromatographic and mass spectrometric (GC/MS) product analyses were employed to characterize and quantify the major reaction products. The rate constants for propargyl radical self‐reactions and propargyl‐methyl cross‐combination reactions were determined through kinetic modeling and comparative rate determination methods. The major products of the propargyl radical combination reaction, at room temperature and total pressure of about 6.7 kPa (50 Torr) consisted of three C₆H₆ isomers with 1,5‐hexadiyne(CHC CH₂ CH₂ CCH, about 60%); 1,2‐hexadiene‐5yne (CH₂CC CH₂ CCH, about 25%); and a third isomer of C₆H₆ (∼15%), which has not yet been, with certainty, identified as being the major products. The rate constant determination in the propargyl‐methyl mixed radical system yielded a value of (4.0 ± 0.4) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ for propargyl radical combination reactions and a rate constant of (1.5 ± 0.3) × 10⁻¹⁰ cm³ molecule⁻¹ s⁻¹ for propargyl‐methyl cross‐combination reactions. The products of the methyl‐propargyl cross‐combination reactions were two isomers of C₄H₆, 1‐butyne (about 60%) and 1,2‐butadiene (about 40%). © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 118–124, 2000     

Syntheses and characterization of [Ru(η5-C5H5) (AsPh3)(L)X] and [Ru(η5-C5H5)(AsPh3)(L)(MeCN)]+mY− (L = PPh3 or AsPh3; X = F,Cl, Br,I, CN,H or SnCl3; Y = HgCl3, Zn2Cl6 or BPh4; m = 1 or 2)

The syntheses of the complexes [(η⁵-C₅H₅)Ru(AsPh₃)(L)X] (L = PPh₃ or AsPh₃; X = Cl, F, Br, I, H, CN or SnCl₃) and [(η⁵-C₅H₅)Ru(AsPh₃)(L)(MeCN)]⁺Y⁻ (Y = HgCl₃, BPh₄ or Zn₂Cl₆) are described. They were characterized by elemental analyses, IR, UV and visible, PMR spectroscopy, X-ray powder diffraction, and mass spectral studies.     

(PPh4)2[MoN(N3)3Cl]2; Synthese,IR-Spektrum und Kristallstruktur

(PPh₄)₂[MoN(N₃)₃Cl]₂; Synthesis, IR Spectrum, and Crystal Structure The title compound is formed in the reaction of molybdenum (II) benzoate with trimethylsilyl azide and PPh₄Cl in dichloro methane forming dark red single crystals. A PPh₃Me⊕ salt of the ion [MoN(N₃)₃Cl]₂^2? is obtained from (PPh₃Me)₂MoNCl₄] treated with silver azide in CH₂Cl₂ suspension. The solvent CH₂Cl₂ participates in both reactions as oxidizing agent. (PPh₄)₂[MoN(N₃)₃Cl₂ is characterized by a structural analysis based upon X-ray data: space group P1 , Z = 1, a = 1050.7 pm; b = 1185.4 pm; c = 1190.8 pm; α = 98.90°; β = 106.87°; γ = 103.97° (4505 independent, observed reflexions, R = 0.039). The compound consists of PPh₄⊕ cations and centrosymmetric anions [MoN(N₃)₃Cl₂^2? in which the molybdenum atoms are bridged by the N_α atoms of two azide groups; the resulting Mo? N bond lengths are 208 pm and 260 pm. In trans position to the long Mo? N bond the terminal nitrido ligand is situated, the Mo?N distance of 164 pm corresponds to a triple bond. Two terminal azido ligands and the chloro ligand are filling up the coordination sphere of the molybdenum atoms to a coordination number of six. The i.r. spectrum is reported and assigned.     

Über die Reaktionen von N-Chloracetonimin mit Molybdänpentachlorid und Wolframhexachlorid Die Kristallstruktur von Me2CNH2[MoOCl4]

Reactions of N-Chloroacetoneimine with Molybdenum Pentachloride and Tungsten Hexachloride. Crystal Structure of Me₂C?NH₂[MoOCl₄] WCl₆ reacts with N-chloroacetoneimine under elimination of chlorine and formation of pentachloro-isopropylideneimino-tungsten(VI), Cl₅W?N?CMe₂, a brown-black crystal powder, which was characterized by i.r. spectroscopy. MoCl₅ reacts in a similar way, although only a product mixture can be obtained. Partial hydrolysis of this mixture yields isopropylideneiminium-tetrachlorooxomolybdate(V), Me₂C?NH₂⁺[MoOCl₄]^?, of which the crystal structure was determined (2323 unique observed reflexions, R = 0.049). Space group P2₁/c, Z = 4, a = 878.6, b = 907.2, c = 1252.2 pm, β = 91.29°. The compound consists of Me₂C?NH₂⁺ ions with a planar arrangement of the skeletal atoms and a CN bond length of 126.7 pm and of dimeric, centrosymmetric anions [MoOCl₄]₂^2? having Mo atoms linked via asymmetric chloro bridges (MoCl distances 238.4 and 307.6 pm). The longer Mo? Cl contacts are located in the trans-positions of the terminal oxoligands (MoO distance 164 pm).     

Influence of the chloride counterion on the redox reactivity of tetraammineplatinum(II) cation with octacyanotungstate(V) anion: Crystal structure of [Pt(NH3)4]2[W(CN)8]

The redox reaction between [Pt(NH₃)₄]²⁺ and [W(CN)₈]³⁻ in the presence of Cl⁻ anions in aqueous solution affords single crystals of [Pt^II(NH₃)₄]₂[W^IV(CN)₈] and [Pt^IV(NH₃)₄Cl₂]Cl₂. Trapped cyano ligands of [W(CN)₈]⁴⁻ rectangular antiprisms of D₂ point symmetry between parallel Pt(II) square planes show that the inner-sphere redox pathway is prohibited. The presence of Cl⁻ counterions enables the formation of [Pt(NH₃)₄Cl₂]Cl₂ as the product of the rare outer-sphere pathway of the oxidation of Pt(II) by [W(CN)₈]³⁻.     

Die Reaktion von Ph3AsCl2 mit Acetonitril. Kristallstrukturen von [Ph3AsNC(Me)C(AsPh3)CN]+Cl– und des Palladium‐Molekülkomplexes [Ph3AsNC(Me)C(AsPh3)CN–PdCl3]

The Reaction of Ph₃AsCl₂ with Acetonitrile. Crystal Structures of [Ph₃AsNC(Me)C(AsPh₃)CN]⁺Cl^– and of the Palladium Molecular Complex [Ph₃AsNC(Me)C(AsPh₃)CN–PdCl₃] In the presence of potassium hydride the reaction of Ph₃AsCl₂ with acetonitrile leads to [Ph₃AsNC(Me) · C(AsPh₃)CN]⁺Cl^– ( 1 ), which is characterized by its infrared spectrum and by a crystal structure analysis. 1 can be explained as an insertion reaction of acetonitrile into an ylidic As–C bond of the primarily formed [(Ph₃As)₂CCN]Cl. 1 : Space group P1, Z = 2, lattice dimensions at –70 °C: a = 991.9(1), b = 1255.2(1), c = 1381.3(1) pm, α = 81.64(1)°, β = 80.12(1)°, γ = 78.17(1)°; R₁ = 0.051. 1 reacts with palladium(II) chloride to give the molecular complex [Ph₃AsNC(Me)C(AsPh₃)CN–PdCl₃] ( 2 ) with zwitterionic structure. The fragment {PdCl₃^–} is terminally bonded at the nitrogen atom of the CCN group of the cation of 1 in a linear arrangement CCNPd. 2 · CH₃CN: Space group P2₁, Z = 2, lattice dimensions at –90 °C: a = 1079.2(1), b = 1261.5(1), c = 1560.9(1) pm; β = 110.20(1)°; R₁ = 0.0283.     

Synthesis of ladder polymers containing polydiacetylene backbones connected with methylene chains and their optical properties

The polymers consisting of polydiacetylene (PDA) backbones were obtained from the novel monomer derivatives, R CC CC R′ CC CC R [where R =  (CH₂)₄OCONHCH₂COOC₄H₉, R′ =  (CH₂)_n ; n = 2, 4, 8] [4BCMU4A(n)], in which linear methylene chain is sandwiched between two diacetylene moieties by solid-state 1,4-addition reaction. The polymerization process was investigated in detail by using spectroscopic techniques such as solid-state ¹³C-NMR, visible absorption, and IR absorption spectra. It was estimated that the polymerization of 4BCMU4A(8) and 4BCMU4A(4) takes place by two consecutive 1,4-addition reactions to form two PDA backbones, which constitute the two poles of the respective ladders. The bridging methylene chain length in the monomer was found to play a vital role as far as the polymerization process is concerned. Thus, the monomers with eight or four methylene units could form the ladder–PDAs by a two-step process, whereas the monomer containing two methylene units could only undergo one-step of 1,4-addition reaction. Further, it was found that the crystallinity of the polymers depends on the methylene chain length in the monomers, 4BCMU4A(8) being the most crystalline of all. These structural features strongly affect their absorption spectra. The third-order nonlinear optical susceptibilities (χ⁽³⁾) for these polymers were measured using third-harmonic generation method. The largest χ⁽³⁾ value obtained was 3.4 × 10⁻¹¹ esu for the poly[4BCMU4A(8)] thin film in resonant region. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3537–3548, 1999     

Reductive nitrosylation of tetraoxometallates—XI. Molybdate hydroxylamine reaction in the presence of cyanide: Synthesis of mono- and dinitrosyl cyan

The new molybdenum cyanonitrosyl complexes, R₂[Mo(NO)(CN)₅]·2H₂O (R = Ph₄P and Bu₄N) and [Mo(NO)(CN)₃(L-L)]·H₂O [L-L =     

Luminescent Pincer Platinum(II) Complexes with Emission Quantum Yields up to Almost Unity: Photophysics,Photoreductive C?C Bond Formation,and Materials Applications

Luminescent pincer‐type Pt^II complexes supported by C‐deprotonated π‐extended tridentate R C^N^N R′ ligands and pentafluorophenylacetylide ligands show emission quantum yields up to almost unity. Femtosecond time‐resolved fluorescence measurements and time‐dependent DFT calculations together reveal the dependence of excited‐state structural distortions of [Pt(R C^N^N R′)(CC‐C₆F₅)] on the positional isomers of the tridentate ligand. Pt complexes [Pt(R‐C^N^N R′)(CC‐Ar)] are efficient photocatalysts for visible‐light‐induced reductive C C bond formation. The [Pt(R‐C^N^N R′)(CC‐C₆F₅)] complexes perform strongly as phosphorescent dopants for green‐ and red‐emitting organic light‐emitting diodes (OLEDs) with external quantum efficiency values over 22.1 %. These complexes are also applied in two‐photon cellular imaging when incorporated into mesoporous silica nanoparticles (MSNs).     

Synthese und Kristallstruktur von (PPh4)2[Mo2(S2)2Cl8] · 2 CH3CN und seine topotaktische Umwandlung zu (PPh4)2[Mo2(S2)2Cl8]

Synthesis and Crystal Structure of (PPh₄)₂[Mo₂(S₂)₂Cl₈] · 2 CH₃CN and its Topotactic Transformation to (PPh₄)₂[Mo₂(S₂)₂Cl₈] MoS₂Cl₃ was prepared from molybdenum and S₂Cl₂ at 200 °C. Its reaction with PPh₄Cl in acetonitrile yielded (PPh₄)₂[Mo₂(S₂)₂Cl₈] · 2 CH₃CN. In vacuum or upon warming, it loses the acetronitrile without degradation of the crystals. According to the X-ray crystal structure determinations both compounds, with and without acetonitrile, are triclinic. They contain the same [Cl₄Mo(μ-S₂)₂MoCl₄]^2– ions, in which the Mo atoms are joined by two disulfido groups and an Mo–Mo bond. Details of the crystal packings and their topotactic transformation are given.