Chiral functionalized bisphosphine ligands: Transition metal complexes of 1,2-bis(tert-Butylchlorophosphino)-1,2-dicarba-closo-dodecaborane(12)

When rac- or meso-1,2-bis(tert-butylchlorophosphino)-1,2-dicarba-closo-dodecaborane(12) (1a or 1b) is reacted with [M(CO)₄(NBD)] (M = Cr, Mo, NBD = norbornadiene), [Mo(CO)₄(EtCN)₂] or [W(CO)₆], rac-[Cr(CO)₄{1,2-(P^tBuCl)₂C₂B₁₀H₁₀}] (2), rac- or meso-[Mo(CO)₄{1,2-(P^tBuCl)₂C₂B₁₀H₁₀}] (3a or 3b) and rac-[W(CO)₄{1,2-(P^tBuCl)₂C₂B₁₀H₁₀}] (4) could be isolated as pure diastereomers. UV irradiation of 1 with [Cr(CO)₆] in moist THF proceeds with hydrolysis and formation of [Cr(CO)₄{1,2-(P(OH)^tBu)₂C₂B₁₀H₁₀}] (5) which contains the metal complex-stabilized phosphinous acid. Compounds 2–5 were characterized spectroscopically (¹H, ³¹P, ¹¹B, ¹³C NMR), by mass spectrometry and by X-ray structure determination.     

Eine neue Synthese von Tetrachlordiphosphan sowie Untersuchungen zur 1,2-Addition an Cycloalkene

A New Synthesis of Tetrachlorodiphosphane and Investigations Concerning the 1,2-Addition to Cycloalkenes . The phosphorus subhalide P₂Cl₄ has been synthesized by co-condensation of PCl₃ and Cu vapour in 14% yield. The ³¹P-NMR chemical shift of P₂Cl₄ has the value of δ=155. P₂Cl₄ decomposes during several hours at 0°C in a N₂ atmosphere by a disproportionation process to yield PCl₃ and a yellow polymeric compound of the approximately composition (PCl)_x. P₂Cl₄ is flammable in air to give POCl₃ and (PCl)_x. Investigations regarding the addition of P₂Cl₄ to cyclooctyne, cyclohexene, and cyclohexa-1,4-diene has been carried out. Surprisingly, cyclooctyne does not react with P₂Cl₄ but cyclohexene as well as cyclohexa-1,4-diene undergo 1,2-addition to yield the trans-1,2-bis(dichlorophosphino) substituted carbonhydrides. By derivatization with Me₃Si—NMe₂ the corresponding trans-1,2-bis[bis(dimethylamino)phosphino] compounds are synthesized.     

1,2-Diphosphaferrocene als Liganden in Übergangsmetallkomplexen. Röntgenstrukturanalyse von [(η5-1,3-tBu2C5H3){η5-1,2-[Co2(CO)6]-3,4-(Me3SiO)2-5-(Me3Si)P2C3}]

1,2-Diphosphaferrocenes as Ligands in Transition Metal Complexes. X-Ray Structure Analysis of [(η⁵-1,3-tBu₂C₅H₃){η⁵-1,2-[Co₂(CO)₆]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}] Reaction of metallo-1,2-diphosphapropene (η⁵-tBuC₅H₄)(CO)₂Fe? P(SiMe₃)? P?C(SiMe₃)₂ with (Z-cyclooctene)Cr(CO)₅ afforded the pentacarbonylchromium adduct of a 1,2-diphosphaferrocene [(η⁵-tBuC₅C₅H₄){η⁵-1-[Cr(CO)₅]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 1 c ). Diphosphaferrocene [(η⁵-tBuC₅H₄){η⁵-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 2 c ) was formed when (η⁵-tBuC₅H₄)(CO)₂FeBr was treated with (Me₃Si)₂P? P?C(SiMe₃)₂ in toluene at 60°C. Photolysis of molybdenum- and tungsten hexacarbonyl in the presence of [(η⁵-1,3-tBu₂C₅H₃){η⁵-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 2 b ) gave the pentacarbonylmetal adducts 8 (M = Mo) and 9 (M = W), respectively. A corresponding manganese derivative resulted from the photochemical reaction of 2 b and (MeC₅H₄)Mn(CO)₃. Treatment of 2 b with Co₂(CO)₈ yielded trinuclear [(η⁵-1,3-tBu₂C₅H₃){η⁵-1,2-[Co₂(CO)₆]-3,4-(Me₃SiO)₂-5-(Me₃Si)P₂C₃}Fe] ( 11 ). Constitution and configuration of compounds 1 c, 2 c, 8 – 11 were determined by elemental analyses and spectra (IR, ¹H-, ¹³C-, ³¹P-NMR, MS). In addition the molecular structure of 11 was established by single crystal X-ray analysis.     

Bis(1,2-dimethoxyethan-O,O′)lithium-phosphanid, -arsanid und -chlorid – drei neue Vertreter des Bis(1,2-dimethoxyethan-O,O′)lithium-bromid-Typs

Metal Derivatives of Molecular Compounds. IX. Bis(1,2-dimethoxyethane- O,O′ )lithium Phosphanide, Arsanide, and Chloride – Three New Representatives of the Bis(1,2-dimethoxyethane- O,O′ )lithium Bromide Type Experiments to obtain thermally unstable lithium silylphosphanide at –60 °C from a 1,2-dimethoxyethane solution resulted in the isolation of its dismutation product bis(1,2-dimethoxyethane-O,O′)lithium phosphanide ( 1 ). The homologous arsanide 2 precipitated after a frozen solution of arsane in the same solvent had been treated with lithium n-butanide at –78 °C. Unexpectedly, too, the analogous chloride 3 and bromide 4 were formed in reactions of 1-chloro-2,2-bis(trimethylsilyl)-1λ³-phosphaethene with (1,2-dimethoxyethane-O,O′)lithium bis(trimethylsilyl)stibanide and of lithium 1,2,3,4,5-pentaphenyl-2,3-dihydro-1λ³-phosphol-3-ide with ω-bromostyrene, respectively. The monomeric complexes 1 {–100 ± 3 °C; a = 1391.1(4); b = 809.8(2); c = 1249.1(3) pm; β = 102.84(2)°}, 2 {–100 ± 3 °C; a = 1398.3(4); b = 819.8(3); c = 1258.5(4) pm; β = 103.35(2)°} and 3 {–100 ± 3 °C; a = 1308.4(2); b = 788.2(1); c = 1195.6(1) pm; β = 95.35(1)°} crystallize in the monoclinic space group C2/c with four solvated ion pairs in the unit cell; they are isotypic with bis(1,2-dimethoxyethane-O,O′)lithium bromide ( 4 ) {–73 ± 2 °C; a = 1319.0(2); b = 794.1(1); c = 1214.3(2) pm; β = 96.22(1)°}, already studied by Rogers et al. [13] at room temperature. The neutral complexes show a trigonal bipyramidal configuration of symmetry C₂, pnicogenanide or halide anions occupying equatorial sites {Li–P 260.4(4); Li–As 269.8(6); Li–Cl 238.6(7); Li–Br 256.3(10) pm} and the chelate ligands spanning equatorial and axial positions {Li–O_eq 205.4(4) to 207.4(4); Li–O_ax 208.9(3) to 215.5(2) pm}. The coordination within the (dme)₂Li fragment, the Li–X distances (X = P, As, Cl, Br), the structure of the chelate rings, and the packing of the neutral complexes are discussed in detail.     

Photochemical reactions of metal carbonyls [M(CO)6 (M=Cr,Mo, W)] with N,N′ -bis(salicylidene)-1,2-bis- ( o -aminophenoxy)ethane

The complexes [M(CO)₄(η²-H₂L)] [M?=?Cr; 1, Mo; 2, W; 3] have been synthesized by photochemical reactions of VIB metal carbonyls [M(CO)₆] [M?=?Cr,?Mo,?W] with N,N′-bis(salicylidene)-1,2-bis-(o-aminophenoxy)ethane (H₂L) in THF and characterized by elemental analyses, FTIR, ¹H?NMR and mass spectra. The H₂L ligand is coordinated to the central metal as a bidentate ligand via the central azomethine nitrogen atoms in 1–3.     

Synthese,Struktur und Reaktivität von η3‐1,2‐Diphosphaallylkomplexen sowie von [{(η5‐C5H5)(CO)2W–Co(CO)3}{μ‐AsCH(SiMe3)2}(μ‐CO)]

Syntheses, Structure and Reactivity of η³‐1,2‐Diphosphaallyl Complexes and [{(η⁵‐C₅H₅)(CO)₂W–Co(CO)₃}{μ‐AsCH(SiMe₃)₂}(μ‐CO)] Reaction of ClP=C(SiMe₂iPr)₂ ( 3 ) with Na[Mo(CO)₃(η⁵‐C₅H₅)] afforded the phosphavinylidene complex [(η⁵‐C₅H₅)(CO)₂Mo=P=C(SiMe₂iPr)₂] ( 4 ) which in situ was converted into the η¹‐1,2‐diphosphaallyl complex [η⁵‐(C₅H₅)(CO)₂Mo{η³‐tBuPPC(SiMe₂iPr)₂] ( 6 ) by treatment with the phosphaalkene tBuP=C(NMe₂)₂. The chloroarsanyl complexes [(η⁵‐C₅H₅)(CO)₃M–As(Cl)CH(SiMe₃)₂] [where M = Mo ( 9 ); M = W ( 10 )] resulted from the reaction of Na[M(CO)₃(η⁵‐C₅H₅)] (M = Mo, W) with Cl₂AsCH(SiMe₃)₂. The tungsten derivative 10 and Na[Co(CO)₄] underwent reaction to give the dinuclear μ‐arsinidene complex [(η⁵‐C₅H₅)(CO)₂W–Co(CO)₃{μ‐AsCH(SiMe₃)₂}(μ‐CO)] ( 11 ). Treatment of [(η⁵‐C₅H₅)(CO)₂Mo{η³‐tBuPPC(SiMe₃)₂}] ( 1 ) with an equimolar amount of ethereal HBF₄ gave rise to a 85/15 mixture of the saline complexes [(η⁵‐C₅H₅)(CO)₂Mo{η²‐tBu(H)P–P(F)CH(SiMe₃)₂}]BF₄ ( 18 ) and [Cp(CO)₂Mo{F₂PCH(SiMe₃)₂}(tBuPH₂)]BF₄ ( 19 ) by HF‐addition to the PC bond of the η³‐diphosphaallyl ligand and subsequent protonation ( 18 ) and/or scission of the PP bond by the acid ( 19 ). Consistently 19 was the sole product when 1 was allowed to react with an excess of ethereal HBF₄. The products 6 , 9 , 10 , 11 , 18 and 19 were characterized by means of spectroscopy (IR, ¹H‐, ¹³C{¹H}‐, ³¹P{¹H}‐NMR, MS). Moreover, the molecular structures of 6 , 11 and 18 were determined by X‐ray diffraction analysis.     

Reaktionen von [B12H12–n(OH)n]2–, n = 1, 2 mit Säuredichloriden und Kristallstruktur von Cs2[1,2-B12H10(ox)] · CH3OH

Reactions of [B₁₂H_12–n(OH)_n]^2–, n = 1, 2 with Acid Dichlorides and Crystal Structure of Cs₂[1,2-B₁₂H₁₀(ox)] · CH₃OH By treatment of [B₁₂H₁₁(OH)]^2– with organic and inorganic acid dichlorides in acetonitrile the bridged dicluster compounds [B₁₂H₁₁(ox)B₁₂H₁₁)]^4– ( 1 ), [B₁₂H₁₁(p-OOCC₆H₄COO)B₁₂H₁₁]^4– ( 2 ), [B₁₂H₁₁(m-OOCC₆H₄COO)B₁₂H₁₁]^4– ( 3 ), [B₁₂H₁₁(SO₃)B₁₂H₁₁]^4– ( 4 ), [B₁₂H₁₁(SO₄)B₁₂H₁₁]^4– ( 5 ) are obtained in good yields. The dihydroxododecaborates [1,2-B₁₂H₁₀(OH)₂]^2– and [1,7-B₁₂H₁₀(OH)₂]^2– afford clusters with an anellated ring: [1,2-B₁₂H₁₀(ox)]^2– ( 6 ), [1,2-B₁₂H₁₀(SO₄)]^2– ( 7 ) and [1,7-B₁₂H₁₀(OOC(CH₂)₈COO)]^2– ( 8 ). Isomerically pure [1,7-B₁₂H₁₀(OH)₂]^2– ( 9 ) is formed by reaction of (H₃O)₂[B₁₂H₁₂] with ethylene glycol. All new compounds are characterized by vibrational, ¹¹B, ¹³C and ¹H NMR spectra. The crystal structure of Cs₂[1,2-B₁₂H₁₀(ox)] · CH₃OH (monoclinic, space group P 2₁/c, a = 9.616(2), b = 10.817(1), c = 15.875(6) Å, β = 95.84(8)°, Z = 4) reveals a distortion of the B₁₂ icosahedron caused by the anellated six-membered heteroring.     

1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolan und 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborin: Synthese und Struktur sowie Berechnungen zur Molekülstruktur

1,2-Bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane and 1,2-Bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine: Synthesis and Structure as well as Calculations on the Molecular Structure The diphosphides K₂[(C₆H₅)P? (C₆H₅)P? P(C₆H₅)], 4 or K₂[(tBuP)? (tBuP)₂? P(tBu)], 5 , react with (ClBNMe₂)₂ to form the binary 5-membered ring system 1,2-bis(dimethylamino)-3,4,5-triphenyl-3,4,5-triphospha-1,2-diborolane (C₆H₅P)₃(BNMe₂)₂, 2a , and the 6-membered ring system 1,2-bis(dimethylamino)-3,4,5,6-tetra-tbutyl-3,4,5,6-tetraphospha-1,2-diborine, (tBuP)₄(BNMe₂)₂, 3a , respectively. 2a and 3a could be obtained in a pure form and characterized NMR spectroscopically and by X-ray structure analyses. The two ring systems are folded; 2a exists in the ?envelope”?- 3a in the ?boat”?-conformation. Ab initio computations for 3,4,5-triphospha-1,2-diborolane M5 show that the global minimum is characterized by one B? P double bond. The parent compound geometry M6 is characterized by transannular bonding in the PH? BH? BH? PH moiety which differs in character from those in the four- and five-membered rings (BH)₂(PH)₂ and (BH)₂(PH)₃ M5 d , respectively. Explicit calculation of the influence of amino substituents on boron improved agreement of the bond length between computed and X-ray data.     

Synthesis of 1,2-bis(methoxyamino)cycloalkanes from alicyclic 1,2-bis(hydroxyamines)

Derivatives of 1,4-dihydroxypiperazine-2,3-dione were obtained by reaction of cis-1,2-bis(hydroxyamino)cycloalkanes with diethyl oxalate. Their alkylation with CH₂N₂ or Mel afforded 1,4-dimethoxypiperazine-2,3-diones. Hydrolysis of the latter gave 1,2-bis(methoxyamino)cycloalkanes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 925–929, April, 1996.     

Bildung und Struktur von [μ‐(1,2 : 2‐η‐tBu2P–P){Mo(CO)2cp′}2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXIV. Formation and Structure of [μ‐(1,2 : 2‐η‐^tBu₂P–P){Mo(CO)₂cp′}₂] [cp′Mo(CO)₂]₂ (cp′ = C₅H₄^tBu) reacts with ^tBu₂P–P=P(Me)^tBu₂ to yield the compound [μ‐(1,2 : 2‐η‐^tBu₂P–P){Mo(CO)₂cp′}₂], which crystallizes in the space group P2₁2₁2₁ with a = 1202.42(7), b = 1552.48(8), and c = 1765.3(1) pm.     

Synthesis and characterization of three dinuclear copper(I) complexes of 1,2‐bis(diphenylphosphino)‐1,2‐dicarba‐closo‐dodecaborane

Three dinuclear copper(I) complexes, [Cu₂(µ‐Cl)₂(1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀)₂]·2CH₂Cl₂ ( 1 ), [Cu₂(µ‐Br)₂(1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀)₂]·2THF ( 2 ) and {Cu₂(µ‐I)₂[1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀]₂} ( 3 ) have been synthesized by the reactions of CuX (X = Cl, Br and I) with the closo ligand 1,2‐(PPh₂)₂‐1,2‐C₂B₁₀H₁₀. All these complexes were characterized by elemental analysis, FT‐IR, ¹H and ¹³C NMR spectroscopy and X‐ray structure determination. Single crystal X‐ray structure determinations show that every complex contained di‐µ‐X‐bridged structure involving a crossed parallelogram plane formed by two Cu atoms and two X atoms (X = Cl, Br, I). The geometry at the Cu atom was a distorted tetrahedron, in which two positions were occupied by two P atoms of the PPh₂ groups connected to the two C atoms of carborane (Cc), and the other two resulted from two X atoms which bridged the other Cu atom at the same time. To the best of our knowledge, this is the first example of copper(I) complexes with 1,2‐diphenylphosphino‐1,2‐dicarba‐closo‐dodecaborane as ligand characterized by X‐ray diffraction. The catalytic property of the complex 3 for the amination of iodobenzene with aniline was also investigated. Copyright © 2005 John Wiley & Sons, Ltd.     

Photochemical reactions of <Emphasis Type="Italic">cis</Emphasis>-[(η<Superscript>4</Superscript>-NBD)M(CO)<Subscript>4</Subscript>] (NBD = norbornadiene; M = Cr,Mo) olefin complex with ligand,containing S and N donor atoms

New complexes cis-[M(CO)₄-DABRd] (M = Cr(I), Mo(II) and fac-[M(CO)₃-SAT] (M = Cr(III), Mo(IV)) have been synthesized by the photochemical reactions of cis-[(η⁴-NBD)M(CO)₄] (NBD is norbornadiene; M=Cr, Mo) with 5-(4-dimethylaminobenzylidene) rhodanine (DABRd) and salicylidene-3-amino-1,2,4-triazole (SAT) ligands and characterized by elemental analysis, FT-IR and ¹H NMR spectroscopy, and mass spectrometry. The spectroscopic studies show that the DABRd ligand acts as a bidentate ligand coordinating via both NH-(S)C=S sulfur donor atoms in I and II and SAT ligand behaves as a tridentate ligand coordinating via its all imine nitrogen-C=N-donor atoms in III and IV to the metal center. The article was submitted by the authors in English.     

Komplexchemie P-reicher Phosphane und Silylphosphane. XI [1]. Bildung,Reaktionen und Strukturen von Chromcarbonylkomplexen aus Reaktionen von Li(THF)2[η2-(tBu2P)2P] mit Cr(CO)5 · THF und Cr(CO)4 · NBD

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. XI. Formation, Reactions, and Structures of Chromium Carbonyl Complexes from Reactions of Li(THF)₂[η₂-(^tBu₂P)₂P] with Cr(CO)₅ · THF and Cr(CO)₄ · NBD Reactions of Li(THF)₂[η²-(^tBu₂P)₂P] 1 with Cr(CO)₅ · THF yield Li(THF)₂Et₂O[Cr(CO)₄{η²-(^tBu₂P)₂P}η¹-Cr(CO)₅] 2 and the compounds [Cr(CO)₄{η²-(^tBu₂P)₂PH}] 3 , [Cr(CO)₅{η¹-(^tBu₂P)₂PH}] 4 , (^tBu₂P)₂PH 5 and ^tBu₂PH · Cr(CO)₅ 6 . The formation of 3, 4, 5 and 6 is due to byproducts coming from the synthesis of 1. 2 reacts with CH₃COOH under formation of 3 . After addition of 12-crown-4 1 with NBD · Cr(CO)₄ in THF forms Li(12-crown-4)₂[Cr(CO)₄-{η²-(^tBu₂P)₂P}] 7 (yellow crystals). 7 reacts with CH₃COOH to 3 – which regenerates 7 with LiBu – with Cr(CO)₅THF to compound 2 , with NBD · Cr(CO)₄ in THF to 2 and 3 (ratio 1 : 1). With EtBr, 7 forms [Cr(CO)₄{η²-(^tBu₂P)₂PEt}] 8 , and [Cr(CO)₄{η²-(^tBu₂P)₂PBr}] 9 with BrCH₂? CH₂Br. The compounds were characterized by means of ¹H, ¹³C, ³¹P, ⁷Li NMR spectroscopy, IR spectroscopy, elementary analysis, mass spectra, and 2, 3 and 4 additionally by means of X-ray diffraction analysis. 2 crystallizes in the space group P1 with 2 formula units in the elementary cell; a = 10.137(9), b = 15.295(12), c = 15.897(14) Å; α = 101.82(7), β = 91.65(7), γ = 98.99(7)°; 3 crystallizes in the space group P2_t/n with 4 molecules in the elementary unit; a = 11.914(6), b = 15.217(10), c = 14.534(10) Å; α = 90, β = 103.56(5), γ = 90°. 4 : space group P1 with 2 molecules in the elementary unit; a = 8.844(4), b = 12.291(6), c = 14.411(7) Å, α = 66.55(2), β = 89.27(2), γ = 71.44(2)°.     

Synthesis and molecular structure of [Re2(μ:η-C24H18N4)(CO)6] containing the rtct-tetrakis(2-pyridyl)cyclobutandiyl ligand, derived from the reaction of [Re2(CO)8(MeCN)2] and 1,2-bis(2-pyridyl)ethene

The reaction of the labile compound [Re₂(CO)₈(CH₃CN)₂] with trans-1,2-bis(2-pyridyl)ethene (C₁₂H₁₀N₂) at room temperature in tetrahydrofuran affords the compounds [Re₂(μ:η³-C₁₂H₁₀N₂)(CO)₈] (1) and the oxidative addition product [Re₂(μ-H)(μ:η³-C₁₂H₉N₂)(CO)₇] (2). When the reaction is carried out at temperatures of refluxing tetrahydrofuran, besides compounds 1 and 2, the oxidative addition product [Re₂(μ-H)(μ:η⁴-C₁₂H₉N₂)(CO)₆] (3), the insertion product [Re₂(μ:η⁴-C₁₂H₁₀N₂)(CO)₈] (4) and [Re₂(μ:η⁶-C₂₄H₁₈N₄)(CO)₆] (5) are obtained. Compound 5 contains the organic ligand rtct-tetrakis(2-pyridyl)cyclobutandiyl which is derived from a [2 + 2] cycloaddition of 1,2-bis(2-pyridyl)ethene mediated by its coordination to the bimetallic framework. The molecular structures of 1, 2, 4 and 5 were confirmed by X-ray crystallographic studies.     

Mono- und Di-t-butylcyclopentadienyl-Carbonyl-Komplexe des Eisens und Molybdäns. Die Kristallstruktur von [Cp″Mo(Co)2]2 (Cp″ = n5-C5H3t-Bu2-1,3)

Mono- and Di-t-Butylcyclopentadienyl Carbonyl Complexes of Iron and Molybdenum — Crystal Structure of [Cp″Mo(CO)₂]₂ (Cp″ = n⁵-C₅H₃-t-Bu₂-1,3) Cothermolysis of M(CO)_m (M = Fe, m = 5; M = Mo, m = 6) with t-Bu-substituted cyclopentadienyls constitutes a simple synthesis of complexes of the type [Cp*M(CO)_n]₂ (CP* = n⁵-C₅H₃ (t-Bu), R, R = H, t-Bu; M = Fe, Mo; n = 2, 3). Each synthesis has an optimal temperature. The yield of Fe complexes decreases at temperatures above 130°C because of decomposition of the product. Optimal yields of [Cp*Mo(CO)₃]₂ are obtained at 130–140°C, whereas at 160°C complexes of the type [Cp*Mo(CO)₂]₂ with formal Mo? Mo triple bonds are obtained. The structure of the complexes is discussed on the basis of ¹H-, ¹³C-NMR, IR, and mass spectrometry. The structure of [Cp″Mo(CO)₂]₂ (Cp″ = n⁵-C₅H₃t-Bu₂-1,3) was determined by X-ray crystallography at ?95°C. It crystallises in the space group Pbca, with cell constants a = 1808.6(6), b = 1308.5(4), c = 2507.9(9) pm, Z = 8, R = 0.031 for 3794 reflections. The Mo? Mo bond length of 253.3 pm is very long for a formal triple bond. The Cp″? Mo? Mo? Cp″ axis is non-linear.     

Synthese und Molekülstruktur von [Li(THF)4][{(CO)4Mo}2(μ-PPh2)(μ-PPh2PPh2)]: Die erste Verbindung mit einem 1,3-Dimetalla-cyclopentaphosphan-Gerüst

Synthesis and Molecular Structure of [Li(THF)₄][{(CO)₄Mo}₂(μ-PPh₂)(μ-PPh₂PPh₂)]: The First Compound with an 1,3-Dimetalla-cyclopentaphosphane Ring [Mo(CO)₄(NBD)] (NBD = norbornadiene) reacts with LiPPh₂ and PPh₂PPh₂ in THF at –80 °C to give [Li(THF)₄][{(CO)₄Mo}₂(μ-PPh₂)(μ-PPh₂PPh₂)] ( 1 ). 1 exhibits an A₂X coupling pattern in the ³¹P NMR spectrum. A crystal structure determination showed the presence of bridging phosphanido (PPh₂) and diphosphane ligands (PPh₂PPh₂). The central Mo₂P₃ five-membered ring adopts a half-chair conformation and thus resembles an inorganic cyclopentane.     

Heterobimetallische phosphanido-verbrückte Zweikern-Komplexe - Synthese von cis-rac-[(η-C5H4R)2Zr{μ-PH(2,4,6−iPr3C6H2)}2M(CO)4] (RMe,MCr,Mo; RH,MMo)

Heterobimetallic Phosphanido-bridged Dinuclear Complexes - Syntheses of cis-rac-[(η-C₅H₄R)₂Zr{μ-PH(2,4,6-ⁱPr₃C₆H₂)}₂M(CO)₄] (R?Me, M?Cr, Mo; R?H, M?Mo) The zirconocene bisphosphanido complexes [(η-C₅H₄R)₂Zr{PH(2,4,6-ⁱPr₃C₆H₂)}₂] (R?Me, H) react with [(NBD)M(CO)₄] (NBD?norbornadiene, M?Cr, Mo) to give only one diastereomer of the phosphanido-bridged heterobimetallic dinuclear complexes cis-rac-[(η-C₅H₄R)₂Zr{μ-PH(2,4,6-ⁱPr₃C₆H₂)}₂M(CO)₄] [R?Me, M?Cr ( 1 ), Mo ( 2 ); R?H, M?Mo ( 3 )]. However, no reaction was observed between [(η-C₅H₅)₂Zr{PH(2,4,6-^tBu₃ C₆H₂)}₂] and [Pt(PPh₃)₄]. 1—3 were characterised spectroscopically. For 1—3 , the presence of the racemic isomer was shown by NMR spectroscopy. No reaction was observed at room temperature for 3 and CS₂, (NO)BF₄, Me₃NO or PH(2,4,6-Me₃C₆H₂)₂. With Et₂AlH or PhC?CH decomposition of 3 was observed.     

Metallderivate von Molekülverbindungen. VII. Bis[1,2-bis(dimethylamino)ethan-N,N′]lithium-disilylphosphanid — Synthese und Struktur

Metal Derivatives of Molecular Compounds. VII. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium Disilylphosphanide — Synthesis and Structure Crystalline lithium phosphanides studied so far show a remarkably high diversity of structure types dependent on the ligands at lithium and the substituents at phosphorus. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium disilylphosphanide ( 1 ) discussed here, belongs to the up to now small group of compounds which are ionic in the solid state. It is best prepared from silylphosphane by twofold lithiation with lithium dimethylphosphanide first and subsequent monosilylation with silyl trifluoromethanesulfonate, followed by complexation. As found by X-ray structure determination (wR = 0.038) on crystals obtained from diethyl ether {monoclinic; space group P2₁/c; a = 897.8(1); b = 1 673.6(2); c = 1 466.8(1) pm; β = 90.73(1)° at ?100 ± 3°C; Z = 4 formula units}, the lithium cation is tetrahedrally coordinated by four nitrogen atoms of two 1,2-bis(dimethylamino)ethane molecules. Characteristic parameters of the disilylphosphanide anion are a shortened average P? Si bond length of 217 pm (standard value 225 pm) and a Si? P? Si angle of 92.3°.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 61. Darstellung und Kristallstruktur von Tetramethyltitan-1,2-bis(dimethylphosphino)ethan

Contributions to the Chemistry of Transition Metal Alkyl Compounds. 61. Preparation and Crystal Structure of Tetramethyltitanium-1,2-bis(dimethylphosphino)ethane The title complex 1 was synthesized by addition of 1,2-bis(dimethylphosphino)ethane to a solution of tetramethyltitanium in diethylether. The complex was characterized by ¹H, ¹³C and ³¹P NMR spectra and by X-ray crystal structure analysis. 1 consists of two independent molecules with distorted octahedral structure.     

Beiträge zur Chemie des Phosphors. 239 [1]. Reaktion von Diphosphan(4) mit Diboran(6) und mit THF-Boran: Bildung von Diphosphan-boran,P2H4 · BH3, und Diphosphan-1,2-bis(boran), BH3 · P2H4 · BH3

Contributions to the Chemistry of Phosphorus. 239. On the Reaction of Diphosphane(4) with Diborane(6) and with THF-Borane: Formation of Diphosphane-borane, P₂H₄ · BH₃, and Diphosphane-1,2-bis(borane), BH₃ · P₂H₄ · BH₃ Diphosphane(4) always reacts with diborane(6) in the temperature range of ?118 to ?78°C, to furnish a mixture of diphosphane-borane, P₂H₄ · BH₃ ( 1 ), and diphosphane-1,2-bis(borane), BH₃ · P₂H₄ · BH₃ ( 2 ), in addition to small amounts of triphosphane-1,3-bis(borane), BH₃ · P₃H₅ · BH₃, and phosphane-borane, BH₃ · PH₃, irrespective of the molar ratios of the reactants employed. The formation of the 1 : 1 adduct P₂H₄ · B₂H₆ reported in the literature [4] could not be confirmed. The structures of compounds 1 and 2 were investigated by nuclear magnetic resonance spectroscopy which revealed the complete, homolytic cleavage of diborane(6). As a result of the bonding of one BH₃ group to diphosphane(4), the Lewis basicity of the other PH₂ group is markedly reduced. Similar mixtures of products are obtained when the borane adduct THF · BH₃ is employed in an analogous reaction. In the case of a 1 : 1 molar ratio of P₂H₄ : THF · BH₃ at ?78°C, the reaction furnishes compound 1 exclusively. This product can be isolated in the pure state and is found to be appreciably more stable than diphosphane(4).