Tetrakis(triphenylphosphaniminato)tantalonium-hexachlorotantalat, [Ta(NPPh3)4]TaCl6. Synthese,IR-Spektrum,Kristallstruktur und Ab-initio-Rechnungen am [Ta(NPH3)4]+-Ion

Tetrakis(triphenylphosphane-iminato)tantalonium hexachlorotantalate, [Ta(NPPh₃)₄]TaCl₆. Synthesis, IR Spectrum, Crystal Structure, and ab initio Calculations of the [Ta(NPH₃)₄]⁺ Ion The title compound has been prepared by the reaction of tantalum pentachloride with Me₃SiNPPh₃ in acetonitrile, forming colourless moisture sensitive crystals, which were characterized by IR spectroscopy and by an X-ray structure determination (Space group P1 , Z = 4, 6479 observed unique reflections, R = 0.053. Lattice dimensions at 20°C: a = 1268.4(3), b = 2361.0(6), c = 2400.0(6) pm, α = 85.81(2)°, β = 87.47(3)°, γ = 87.27(3)°). The compound consists of two symmetry-independent cations [Ta(NPPh₃)₄]⁺ and anions TaCl₆^?, respectively. In the cations the tantalum atoms are surrounded in a distorted tetrahedral fashion by the four nitrogen atoms of the phosphane-iminato ligands. The TaN and PN bond lengths in both individuals correspond well with double bonds. According to twisting phenomena of the phenyl rings the TaNP bond angles are different in the two cation species. The investigation is supplemented by ab initio calculations of the [Ta(NPH₃)₄]⁺ ion.     

Bis(triphenylphosphaniminato)niobtrichlorid, [NbCl3(NPPh3)2], ein Komplex mit fünffach koordiniertem Niob

Bis(triphenylphosphorane-iminato)niobium Trichloride, [NbCl₃(NPPh₃)₂], a Complex with Coordination Number Five at the Niobium Atom The title compound has been prepared from niobium pentachloride with Me₃SiNPPh₃ in acetonitrile solution, forming colourless, moisture sensitive crystals. They were characterized by IR spectroscopy and by an X-ray structure determination. [NbCl₃(NPPh₃)₂] crystallizes monoclinically in the space group Cc with four formula units per unit cell, 3682 observed, unique reflections, R = 0.042%. Lattice dimensions at 20°C: a = 1025.1(2); b = 1870.6(6); c = 1832.5(5) pm, β = 91.83(2)°. The niobium atom of the complex is coordinated in a distorted trigonal bipyramidal fashion, while the nitrogen atoms of the two phosphorane iminato ligands are in equatorial position along with one chlorine atom. NbN and PN distances accord with double bonds; with a mean value of 242.0 pm the Nb Cl distances are remarkably long.     

Kristallstrukturen von [TiF3(NPPh3)(HNPPh3)]2 und von HNPPh3

Crystal Structures of [TiF₃(NPPh₃)(HNPPh₃)]₂ and of HNPPh₃ The phosphoraneiminato-phosphaneimine complex [TiF₃(NPPh₃)(HNPPh₃)]₂ was obtained by the reaction of TiF₄ with Me₃SiNPPh₃ in boiling dichloromethane. It crystallizes from 1,2-dichloroethane as yellow crystals which include four molecules C₂H₄Cl₂ per dimeric formula unit. Space group P2₁/n, Z = 2, structure solution with 7270 independent reflections, R = 0.060 for reflections with I > 2σ(I). Lattice dimensions at ?50°C: a = 1417.5, b = 1896.9, c = 1586.6 pm, β = 101.22°. The compound forms centrosymmetric dimeric molecules via μ₂-F bridges with TiF distances of 194.6 and 223.3 pm, the longer one being in trans-position to the N atom of the (NPPh₃)^? ligand. Its TiN bond length of 177.7 pm corresponds with a double bond. The TiN bond length of the HNPPh₃ donor molecule of 213.4 pm is typical for a donor acceptor bond. According to the crystal structure determination the phosphaneimine HNPPh₃ forms monomeric molecules without intermolecular hydrogen bridges with a PN bond length of 152.4 pm. Space group P2₁/c, Z = 4, structure solution with 3229 independent reflections, R = 0.062 for reflections with I > 2σ(I). Lattice dimensions at ?70°C: a = 1460.4, b = 928.9, c = 1096.6 pm, β = 93.35°.     

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.     

Phosphaniminato-Komplexe des Titans. Die Kristallstrukturen von [TiCl2(NPPh3)2] und [TiCl3(NPMe2Ph)(CH3CN)]2

Phosphorane Iminato Complexes of Titanium. The Crystal Structures of [TiCl₂(NPPh₃)₂] and [TiCl₃(NPMe₂Ph)(CH₃CN)]₂ [TiCl₂(NPPh₃)₂] has been prepared by the reaction of [TiCl₃(NPPh₃)] with excess Me₃SiNPPh₃ in a melt at 220°C, forming colourless crystals. [TiCl₃(NPMe₂Ph)(CH₃CN)]₂ is formed as yellow, moisture sensitive crystals from acetontrile solutions of [TiCl₃(NPMe₂Ph)]₂, which on its part has been obtained by the reaction of TiCl₄ with Me₃SiNPMe₂Ph. The complexes are characterized by IR spectroscopy and by crystal structure determinations. [TiCl₂(NPPh₃)₂] . Space group Fdd2, Z = 8, structure refinement with 2875 observed unique reflections, R = 0.039. Lattice dimensions at 19°C: a = 2080.9, b = 3308.5, c = 973.6 pm. The compound forms monomeric molecules with bond lengths TiN of 179.0 pm and PN of 156.8 pm, which correspond with double bonds. The bond angle TiNP is 166.6°. [TiCl₃(NPMe₂Ph)(CH₃CN)]₂ . Space group P1 , Z = 1, structure refinement with 2577 unique reflections, R = 0.039 for reflections with I > 2σ(I). Lattice dimensions at 20°C: a = 856.6, b = 923.1, c = 1008.3 pm, α = 81.23°, β = 71.63°, γ = 81.41°. The compound forms centrosymmetric, dimeric molecules, in which the titanium atoms are linked via chloro bridges TiCl₂Ti with TiCl bond lengths of 243.9 and 270.3 pm. In trans-position to the longer TiCl bonds the nitrogen atoms of the phosphorane iminato groups are coordinated with bond lengths TiN of 173.9 pm and PN of 161.4 pm which again correspond with double bonds. The bond angle TiNP is 156.4°.     

[VCl3(NPPh3)(OPPh3)], ein Phosphaniminato-Komplex von Vanadium(IV)

[VCl₃(NPPh₃)(OPPh₃)], a Phosphorane Iminato Complex of Vanadium(IV) The title compound has been prepared from vanadium tetrachloride and Me₃SiNPPh₃ in the presence of OPPh₃ in CCl₄ solution, forming orange-red, moisture sensitive crystals, which were characterized by an X-ray structure determination. Space group Cc, Z = 4, 2 560 observed unique reflections, R = 0.049. Lattice dimensions at 0°C: a = 1 018(1), b = 1 826(2), c = 1 859(2) pm, β = 93.65(9)° [VCl₃(NPPh₃)(OPPh₃)] forms monomeric molecules, in which the vanadium atom is coordinated in a distorted square pyramidal fashion with the (NPPh₃)^? ligand in apical position. The three chlorine atoms and the oxygen atom of the OPPh₃ molecule occupy the basal positions. The phosphorane iminato group V?N?PPh₃ is nearly linear (bond angle VNP 161.4°), the bond lengths VN (169 pm) and PN (162 pm) correspond with double bonds.     

Phosphaniminato-Komplexe des Schwefels. Synthese und Kristallstrukturen von [SO(Cl)(NPPh3)], [SO2(Cl)(NPPh3)] und [SCl(NPPh3)2]Cl

Phosphorane Iminato Complexes of Sulfur. Synthesis and Crystal Structures of [SO(Cl)(NPPh₃)], [SO₂(Cl)(NPPh₃)], and [SCl(NPPh₃)₂]Cl The title compounds have been prepared by the reaction of Me₃SiNPPh₃ with SOCl₂, SO₂Cl₂, and SCl₂, respectively. They form colourless, moisture sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. [SO(Cl)(NPPh₃)]: Space group P2₁/n, Z = 4, structure determination with 2 434 observed unique reflections, R = 0.047. Lattice dimensions at 19°C: a = 1 304.8, b = 996.5, c = 1 339.5 pm, β = 93.75°. The compound forms monomeric molecules with a remarkably long S? Cl bond of 234.2 pm and distances SN and PN of 154.6 and 161.6 pm, respectively, which agree with double bonds. [SO₂(Cl)(NPPh₃)]: Space group P2₁/n, Z = 4, structure solution with 2 872 observed, unique reflections, R = 0.047. Lattice dimensions at 20°C: a = 956.9, b = 1 909, c = 1 002.0 pm, β = 106.06°. The compound forms monomeric molecules with distances S? Cl of 207.1 pm, SN of 154.5 pm, and PN of 161.6 pm. [SCl(NPPh₃)₂]Cl: Space group P2₁/c, Z = 4, structure solution with 5 224 observed, unique reflections, R = 0.042. Lattice dimensions at 20°C: a = 1 108.6, b = 1 603.8, c = 1 840.5 pm, β = 99.98°. The compound forms ions [SCl(NPPh₃)₂]⁺ and Cl^?. In the cation the sulfur atom is φ-tetrahedrally coordinated with a long S? Cl distance of 248.5 pm and SN bond lengths of 154.5 and 156.0 pm.     

Phosphaniminato-Komplexe des Schwefels. Synthese und Kristallstrukturen von [O3SS(NPPh3)2] · CH3CN, [SO(NPPh3)2] und [SCl(NPMe3)2]Cl

Phosphorane Iminato Complexes of Sulfur. Syntheses and Crystal Structures of [O₃SS(NPPh₃)₂] · CH₃CN, [SO(NPPh₃)₂], and [SCl(NPMe₃)₂]Cl The title compounds have been prepared by the reaction of Me₃SiNPPh₃ with SO₂ and SOCl₂, respectively, and by the reaction of Me₃SiNPMe₃ with S₂Cl₂. They form colourless, moisture sensitive crystals, which were characterized by IR spectroscopy and by crystal structure determinations. [O₃SS((NPPh₃)₂)] · CH₃CN : Space group Pca2₁, Z = 4, structure solution with 4016 observed unique reflections, R = 0.050. Lattice dimensions at ?60°C: a = 1865.1, b = 1168.4, c = 1569.0 pm. The compound has a zwitterionic structure with a S? S bond length of 218.2 pm and bond lengths S? N of 161.2 and P? N of 160.1 pm. [SO(NPPh₃)₂] : Space group P2₁/c, Z = 4, structure solution with 2854 observed unique reflections, R = 0.113. Lattice dimensions at ?50°C: a = 1173.1, b = 1585.6, c = 1619.2 pm, b? = 98.13°. The compound forms monomeric molecules, in which the positions of S and N atoms are disordered in two positions. The bond lengths are S? N 166 pm and P? N 163 pm in average. [SCl(NPMe₃)₂]Cl : Space group P1 , Z = 2, structure solution with 2416 observed unique reflections, R = 0.038. Lattice dimensions at 20°C: a = 613.2, b = 1030.3, c = 1111.4 pm, α = 88.48°, b? = 88.01°, γ = 83.10°. The compound forms ions [SCl(NPMe₃)₂]⁺ and Cl^?. In the cation the sulfur atom is ?-tetrahedrally coordinated with a long S? Cl distance of 246.9 pm and bond lengths S? N of 155.3 pm and P? N of 164.3 pm in average.     

[MoN(NPPh3)3] – ein monomerer Nitrido-Komplex des Molybdäns

[MoN(NPPh₃)₃] – a Monomeric Nitrido Complex of Molybdenum [MoN(NPPh₃)₃] ( 1 ) has been prepared from [MoCl₃(N₃S₂)]₂ and LiNPPh₃ in toluene suspension in good yields. From n-hexane/dichloromethane solutions 1 · 2 CH₂Cl₂ crystallizes as colourless single crystals, which were suitable for a crystal structure determination. 1 forms monomeric molecules with a Mo≡N distance of 166.6 pm for the nitrido ligand, which corresponds to a triple bond, and MoN-bonds of 193.6 pm on average of the NPPh₃^–-ligands, corresponding to shortened single bonds.     

Synthese und Kristallstruktur des Selenyl-Phosphaniminato-Komplexes SeO(NPPh3)2

Synthesis and Crystal Structure of the Selenyl-Phosphoraneiminato Complex SeO(NPPh₃)₂ SeO(NPPh₃)₂ has been prepared from SeO₂ and Me₃SiNPPh₃ in a SeO₂ suspension in acetonitrile, forming colourless crystals. The compound is characterized by IR spectroscopy and by a crystal structure determination. Space group P1 , Z = 2, structure solution with 5 344 observed unique reflections, R = 0.064. Lattice dimensions at ?40°C: a = 931.6, b = 947.6, c = 1 762 pm, α = 77.50°, β = 81.78°, γ = 79.23°. The compound forms monomeric molecules in which the selenium atom is φ-tetrahedrally surrounded with bond lengths SeO = 161.7 pm and SeN = 179.9 and 181.6 pm.     

Phosphaniminato-Komplexe von Titan(IV). Die Kristallstrukturen von [TiCl3(NPEt3)]2, [TiCl3(NPEt3)(THF)2] und [TiCl4{Me2Si(NPEt3)2}]

Phosphoraneiminato Complexes of Titanium(IV). Crystal Structures of [TiCl₃(NPEt₃)]₂, [TiCl₃(NPEt₃)(THF)₂], and [TiCl₄{Me₂Si(NPEt₃)₂}] [TiCl₃(NPEt₃)]₂ ( 1 ) is formed from titanium(IV) chloride and the silylated phosphaneimine Me₃SiNPEt₃ in dichloromethane as reddish-brown, moisture-sensitive crystals. According to the crystal structure analysis these crystals show centrosymmetric Ti₂N₂ four-membered rings with Ti–N distances of 184.7 and 210.3 pm. With tetrahydrofurane 1 forms yellow, moisture sensitive crystals of the solvate [TiCl₃(NPEt₃)(THF)₂] ( 2 ), in which the titanium atom is octahedrally coordinated. The THF molecule which is in trans position to the phosporaneiminato ligand realizes but a very weak Ti–O bond of 238.0 pm, the cis THF molecule shows a Ti–O distance of 213.7 pm. With 173.4 pm along with a TiNP bond angle of 160.0° the TiN distance is very short. The bis(phosphaneimine) complex [TiCl₄{Me₂Si(NPEt₃)₂}] ( 3 ) is formed as colourless crystals in low yield in the reaction of titanium(IV) chloride with Me₃SiNPEt₃ and trimethylcyclopentadienylsilane. In 3 the titanium atom is surrounded by four chlorine atoms in a distorted octahedral fashion and by the two N atoms of the Me₂Si(NPEt₃)₂ molecule with TiN distances of 205.6 pm.     

[Mo(NPPh3)4]2+ [MoNCl3(NPPh3)]2− · C7H8, ein Phosphaniminato-Komplex mit einem Dikation von Molybdän(VI)

[Mo(NPPh₃)₄]²⁺ [MoNCl₃(NPPh₃)]₂^? · C₇H₈, a Phosphoraneiminato Complex with a Dication of Molybdenum(VI). The title compound was prepared by the reaction of MoNCl₃ with Me₃SiNPPh₃ in acetonitrile solution. Red single crystals separated upon addition of toluene. They were characterized by IR spectroscopy and by an X-ray structure determination. (Space group P1 , Z = 2, 6918 observed unique reflections, R = 0.059. Lattice dimensions at 20°C: a = 1 181.4, b = 2 021.4, c =2 409.7pm; α = 65.87°, β = 101.09°, γ= 78.97°). In the dication [Mo(NPPh₃)₄]²⁺ the molybdenum atom is surrounded in a tetrahedral fashion by the four nitrogen atoms of the phosphorane iminato ligands. The MoN and PN bond lengths correspond well with double bonds. In the two anions [MoNCl₃(NPPh₃)]^?, which occur in different conformations, the molybdenum atoms are fivefold coordinated by the terminal nitride ligand Mo?N: in axial positions and by the three chlorine atoms and the nitrogen atom of the (NPPh₃)^? ligand in the equatorial positions.     

Synthesen und Strukturen der Titan(III)‐siloxane [Ti(OSiPh3)3(thf)2] und [Ti(OSiPh3)3(py)2]

Syntheses and Structures of the Titanium(III) Siloxanes [Ti(OSiPh₃)₃(thf)₂] and [Ti(OSiPh₃)₃(py)₂] The new titaniumtrioxysilanes [Ti(OSiPh₃)₃(thf)₂] ( 1 ) and [Ti(OSiPh₃)₃(py)₂] ( 2 ) have been obtained from the reaction of titaniumtrichloride with LiOSiPh₃ in the presence of the corresponding bases tetrahydrofurane (thf) and pyridine (py). From the crystal structures of both compounds it is evident that the titanium atoms are in the centres of trigonal‐bipyramidal coordination figures, with the donor atoms in axial positions. The compounds 1 and 2 have slightly different structures (mean values: 1 : Ti‐O(Si) 1.897(9), Ti‐O(C) 2.136(8) Å; 2 : Ti‐O 1.902(9), Ti‐N2.252(8) Å) and have a single absorption band in the visible region of the UV‐spectrum. The exchange of the thf‐ligands in 1 by pyridine (in high molar excess) seems to be hindered as deduced from UV‐spectroscopy.     

[W(NPPh3)4]Cl2 — Ein Phosphaniminato-Komplex mit einem Wolfram-Dikation

[W(NPPh₃)₄]Cl₂ — a Phosphoraneiminato Complex with a Dication of Tungsten The title compound has been prepared by the reaction of Me₃SiNPPh₃ with WNCl₃ and WO₂Cl₂, respectively, in acetonitrile, forming colourless crystals, which were characterized by IR spectroscopy and by an X-ray structure determination. Space group P2₁/n, Z = 4, 4 424 observed unique reflections, R = 0.045. Lattice dimensions at 20°C: a = 1 206.5(2), b = 2 225.3(2), c = 2 421.0(3) pm, β = 101.09(1)°. In the dication [W(NPPh₃)₄]²⁺ the tungsten atom is surrounded in a tetrahedral fashion by the four nitrogen atoms of the phosphoraneiminato ligands. The bond lengths WN and PN correspond with double bonds.     

[(Me3PN)3SNS(NPMe3)2]Cl2, ein gemischtvalenter Phosphaniminato-Komplex des Schwefels

[(Me₃PN)₃SNS(NPMe₃)₂]Cl₂, a Mixed Valenced Phosphorane Iminato Complex of Sulfur The title compound has been prepared from trithiazyl chloride and the silylated phosphaneimine Me₃SiNPMe₃ in acetonitrile solution, forming red crystals, which were characterized by IR spectroscopy and by a crystal structure determination. Space group P2₁/c, Z = 4, structure solution with 4250 independent reflections, R = 0.054. Lattice dimensions at 20°C: a = 1077.8, b = 2036.6, c = 1480.5 pm, β = 102.39°. The compound consists of dications [(Me₃PN)₃SNS(NPMe₃)₂]²⁺ and chloride ions. In the cations the sulfur atoms of oxidation number +VI and +IV are connected by an asymmetric, bent nitrido bridge with SN bond lengths of 156.9 and 167.0 pm.     

[Zr2Cl4(NPMe3)4(HNPMe3)] · CH3CN,ein Phosphaniminato-Komplex mit ZrN-Doppelbindungen

[Zr₂Cl₄(NPMe₃)₄(HNPMe₃)] · CH₃CN, a Phosphorane Iminato Complex with Zr?N Double Bonds The title compound has been prepared from a molten mixture of ZrCl₄ with Me₃SiNPMe₃ in the presence of potassium fluoride and subsequent extraction with acetonitrile. According to the crystal structure determination the zirconium atoms are linked by three μ₂-N atoms of two NPMe₃^? groups and by the HNPMe₃ molecule. Two terminal bounded chlorine atoms and a terminally coordinated NPMe₃^? ligand complete the distorted octahedral surrounding of the zirconium atoms thus forming an edge sharing double octahedron. The ZrN bond lengths of the terminal NPMe₃^? groups of 194.6 pm correspond with double bonds.     

Phosphaniminato-Trichloroselenate(II): Synthese und Kristallstrukturen von [SeCl(NPPh3)2]+SeCl3− und [Me3SiN(H)PMe3]2+[Se2Cl6]2−

Phosphorane Iminato-Trichloroselenates(II): Syntheses and Crystal Structures of [SeCl(NPPh₃)₂]⁺SeCl₃^? and [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2? [SeCl(NPPh₃)₂]⁺SeCl₃^? has been synthesized by the reaction of Se₂Cl₂ with Me₃SiNPPh₃ in acetonitrile solution, forming orangered crystals, whereas red crystals of [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2? were obtained by the reaction of Me₃SiNPMe₃ with SeOCl₂ in acetonitrile solution. Both complexes were characterized by X-ray structure determinations. [SeCl(NPPh₃)₂]⁺SeCl₃^?: Space group P2₁/n, Z = 4, structure solution with 7 489 observed unique reflections, R = 0.057. Lattice dimensions at ?60°C: a = 1 117.0; b = 2 241, c = 1 407.5 pm, β = 95.61°. In the cation [SeCl(NPPh₃)₂]⁺ the selenium atom is φ-tetrahedrally coordinated by the chlorine atom and by the nitrogen atoms of the phosphorane iminato ligands, whereas the anion SeCl₃^? has a T-shaped structure with φ-trigonal-bipyramidale surrounding of the selenium atom. [Me₃SiN(H)PMe₃]₂⁺[Se₂Cl₆]^2?: Space group P2₁/c, Z = 4, structure solution with 2 093 observed unique reflections, R = 0.080. Lattice dimensions at ?70°C: a = 956, b = 828, c = 1 973 pm, β = 93.80°. The structure consists of [Me₃SiN(H)PMe₃]⁺ ions and planar [Se₂Cl₆]^2? anions, in which the selenium atoms are bridged nearly symmetrically by two chlorine atoms.     

Tris(triphenylphosphaniminato)boran,B(NPPh3)3

Tris(triphenylphosphoraneiminato)borane, B(NPPh₃)₃ B(NPPh₃)₃ has been prepared by the reaction of BF₃ · OEt₂ with LiNPPh₃ in toluene/tetrahydrofuran. Moisture sensitive single crystals of B(NPPh₃)₃ · 0.5 C₇H₈ were obtained and characterized by NMR and IR spectroscopy as well as by a crystal structure determination. Space group P2₁/n, Z = 4, lattice dimensions at –70 °C; a = 2147.8(3), b = 978.5(2), c = 2423.8(2) pm, β = 114.11(1)°, R₁ = 0.070. The compound forms monomeric molecules with a planar BN₃ skeleton and BN bond lengths of 144.7 pm on average.     

Phosphaniminate von Alkalimetallen: Die Kristallstrukturen von [KNPCy3]4, [KNPCy3]4·2OPCy3, [CsNPCy3]4·4OPCy3 und [Li4(NPPh3)(OSiMe2NPPh3)3(DME)]

The alkalimetal phosphoraneiminates [KNPCy₃]₄, ( 1 ) [KNPCy₃]₄·2OPCy₃ ( 2 ) and [CsNPCy₃]₄·4OPCy₃ ( 3 ) (Cy = cyclohexyl) which are obtainable by the reaction of pottassium amide or cesium amide with Cy₃PI₂ or Cy₃PBr₂ in liquid ammonia, as well as the lithium derivative [Li₄(NPPh₃)(OSiMe₂NPPh₃)₃(DME)] ( 4 ) have been characterized by crystal structure determinations. 4 has been formed by the insertion reaction of silicon greaze (‐OSiMe₂)n into the LiN bonds of [LiNPPh₃]₆ in DME solution (DME = 1, 2‐dimethoxyethane). 1 : Space group P&1macr;, Z = 2, lattice dimensions at 193 K: a = 1389.8(1); b = 1408.1(1); c = 2205.2(2) pm; α = 78.952(10)?; β = 81.215(10)?; γ = 66.232(8)?; R1 = 0.0418. 2 : Space group Pbcn, Z = 4, lattice constants at 193 K: a = 2943.6(2); b = 2048.2(1); c = 1893.8(1) pm; R1 = 0.0428. 3 : Space group Cmc2₁, Z = 4, lattice dimensions at 193 K: a = 2881.6(2); b = 2990.2(2); c = 1883.7(2) pm; R1 = 0.0586. 4 ·1/2DME: Space group R&3macr;c, Z = 12, lattice dimensions at 193 K: a = b = 1583.5(1); c = 11755.3(5) pm; R1 = 0.0495. All complexes have heterocubane structures. In 1‐3 they are formed by four alkali metal atoms and by the nitrogen atoms of the (μ₃‐NPCy₃^‐) groups, whereas 4 forms a "heteroleptic" Li₄NO₃ heterocubane.     

Alkalimetall‐Phosphaniminate. Neue Synthesen und die Kristallstrukturen von [RbNPPh3]6 und [CsNPPh3]4

Alkali Metal Phosphoraneiminates. New Syntheses and Crystal Structures of [RbNPPh₃]₆ and [CsNPPh₃]₄ The alkali‐metal phosphoraneiminates MNPPh₃ with M = Na, K, Rb, Cs have been synthesized by reactions of Ph₃PI₂ with the alkali‐metal amides in liquid ammonia and were obtained as pure samples by subsequent extraction with toluene. The ethyl derivative KNPEt₃ has been prepared by an analogous route from Et₃PBr₂ and extraction with hexane. Single crystals of the phosphoraneiminates of rubidium and cesium are obtainable by crystallization from toluene and toluene/hexane, respectively. They were suitable for crystal structure determinations. [RbNPPh₃]₆ · 4¹/₂ toluene ( 1 ): space group P1, Z = 2, lattice dimensions at 193 K: a = 1525.5(2); b = 1902.9(2); c = 2178.3(2) pm; α = 95.435(12)°; β = 91.145(12)°; γ = 90.448(12)°; R₁ = 0.0529. The compound forms a Rb₆N₆ skeleton of a double cube with a common face of two rubidium and two nitrogen atoms, the latter being fivefold coordinated by four rubidium atoms and the phosphorus atom. [CsNPPh₃]₄ · 2 toluene · 3³/₄ hexane ( 2 a ): space group Fd3, Z = 8, lattice dimensions at 123 K: a = b = c = 2679.7(1) pm; R₁ = 0.0405. [CsNPPh₃]₄ · 2 toluene ( 2 b ): space group P2₁/n, Z = 4, lattice dimensions at 193 K: a = 1418.9(1); b = 2258.9(1); c = 2497.6(1) pm; β = 91.055(6)°; R₁ = 0.0278. Both cesium compounds form Cs₄N₄ heterocubane structures which are different by means of the packing and by different bond angles at the cesium and nitrogen atoms.