Synthese und Charakterisierung neuer cyclischer und käfigartiger Indium‐Phosphor‐ und Indium‐Arsen‐Verbindungen

Synthesis and Characterization of New Cyclic and Cage‐like Indium — Phosphorus and Indium — Arsenic Compounds The reaction of InEt₃ with H₂ESiiPr₃ initially yields the cyclic compound [Et₂InP(H)SiiPr₃]₂ ( 2 ). 2 appears as a mixture of cis and trans isomers and has been characterized by ³¹P‐NMR spectroscopy, IR spectroscopy, and mass spectrometry. 2 decomposes in solution under elimination of ethane during a few days to form [EtInPSiiPr₃]₄ ( 3 ) with a cage‐like structure. The analogous arsenic compound [EtInAsSiiPr₃]₄ ( 4 ) can be prepared by reaction of InEt₃ with H₂AsSiiPr₃. Central structural motif of 3 and 4 is an In₄E₄ heterocubane like structure (E = P, As), whereas the reaction of InEt₃ with H₂PSiMe₂Thex (Thex = CMe₂iPr) yields [EtInPSiMe₂Thex]₆ ( 5 ) with a hexagonal prismatic structure.     

Aromatic Osmacyclopropenefuran Bicycles and Their Relevance for the Metal‐Mediated Hydration of Functionalized Allenes

The aromatic osmacyclopropenefuran bicycles [OsTp{κ³‐C¹,C²,O‐(C¹H₂C²CHC(OEt)O)}(PⁱPr₃)]BF₄ (Tp=hydridotris(1‐pyrazolyl)borate) and [OsH{κ³‐C¹,C²,O‐(C¹H₂C²CHC(OEt)O)}(CO)(PⁱPr₃)₂]BF₄, with the metal fragment in a common vertex between the fused three‐ and five‐membered rings, have been prepared via the π‐allene intermediates [OsTp(η²‐CH₂=CCHCO₂Et)(OCMe₂)(PⁱPr₃)]BF₄ and [OsH(η²‐CH₂=CCHCO₂Et)(CO)(OH₂)(PⁱPr₃)₂]BF₄, and their aromaticity analyzed by DFT calculations. The bicycle containing the [OsH(CO)(PⁱPr₃)₂]⁺ metal fragment is a key intermediate in the [OsH(CO)(OH₂)₂(PⁱPr₃)₂]BF₄‐catalyzed regioselective anti‐Markovnikov hydration of ethyl buta‐2,3‐dienoate to ethyl 4‐hydroxycrotonate.     

Untersuchungen zu Reaktionen des Diphosphanylsilans iPr2Si(PH2)2 mit Erdalkalimetallsilazaniden

The reaction of iPr₂Si(PH₂)₂ ( 1 ) with [Ca{N(SiMe₃)₂}₂(THF)₂] at 25 °C in molar ratio 1:1 yields the compound [Ca₃{iPr₂Si(PH)₂}₃(THF)₆] ( 2 ). Compound 2 consists of two Ca₂P₃ trigonal bipyramids with one conjoint calcium corner and SiiPr₂ bridged phosphorus atoms. In contrast, the same reaction at 60 °C yield the complex [Ca({P(SiiPr₂)₂PH}₂(THF)₄] ( 3 ). The isotype strontium compound [Sr({P(SiiPr₂)₂PH}₂(THF)₄] ( 4 ) was obtained from the reaction of iPr₂Si(PH₂)₂ with [Sr{N(SiMe₃)₂}₂(DME)₂]. The Compounds 2 – 4 were characterised by single crystal X‐ray diffraction, elemental analysis as well as IR and NMR spectroscopic techniques.     

Substituted Ferrocenylboranes – Potential Ligand Precursors for ansa‐ Metallocenes,Constrained Geometry Complexes and ansa‐Diamido Complexes

A wide range of potential ligand precursors and related compounds have been synthesized from ferrocenyldibromoborane and ferrocenylenebis(dibromoborane) via salt elimination reactions. These comprise ligand precursors suitable for the preparation of (i) ansa‐metallocenes such as [FcB(η¹‐C₅H₅)₂] ( 2 ), [FcB(1‐C₉H₇)₂] ( 3 ), [FcB(3‐C₉H₇)₂] ( 4 ) and [1,1′‐fc{B(3‐C₉H₇)₂}₂] ( 11 ), (ii) constrained geometry complexes such as [FcB(1‐C₉H₇)N(H)Ph] ( 7 ) and [FcB(3‐C₉H₇)N(H)Ph] ( 8 ), (iii) ansa‐diamido complexes such as [FcB(N(H)Ph)₂] ( 9 ) as well as (iv) the related compounds [FcB(Br)N(H)tBu] ( 5 ), [FcB(Br)N(H)Ph] ( 6 ), [1,1′‐fc{B(Br)N(SiMe₃)₂}₂] ( 12 ) and [1,1′‐fc{B(Br)NiPr₂}₂] ( 13 ) (Fc = ferrocenyl, fc = ferrocenylene, C₅H₅ = cyclopentadienyl, C₉H₇ = indenyl). All new compounds have been characterised by multinuclear NMR spectroscopic techniques and in the case of 7 and 12 by X‐ray diffraction methods.     

Iridium(I)‐ und Iridium(III)‐Komplexe mit Triisopropylarsan als Ligand

Iridium(I) and Iridium(III) Complexes with Triisopropylarsane as Ligand The ethene complex trans‐[IrCl(C₂H₄)(AsiPr₃)₂] ( 2 ), which was prepared from [IrCl(C₂H₄)₂]₂ and AsiPr₃, reacted with CO and Ph₂CN₂ by displacement of ethene to yield the substitution products trans‐[IrCl(L)(AsiPr₃)₂] ( 3 : L = CO; 4 : L = N₂). UV irradiation of 2 in the presence of acetonitrile gave via intramolecular oxidative addition the hydrido(vinyl)iridium(III) compound [IrHCl(CH=CH₂)(CH₃CN)(AsiPr₃)₂] ( 5 ). The reaction of 2 with dihydrogen led under argon to the formation of the octahedral complex [IrH₂Cl(C₂H₄)(AsiPr₃)₂] ( 7 ), whereas from 2 under 1 bar H₂ the ethene‐free compound [IrH₂Cl(AsiPr₃)₂] ( 6 ) was generated. Complex 6 reacted with ethene to afford 7 and with pyridine to give [IrH₂Cl(py)(AsiPr₃)₂] ( 8 ). The mixed arsane(phosphane)iridium(I) compound [IrCl(C₂H₄)(PiPr₃)(AsiPr₃)] ( 11 ) was prepared either from the dinuclear complex [IrCl(C₂H₄)(PiPr₃)]2 ( 9 ) and AsiPr₃ or by ligand exchange from [IrCl(C₂H₄)(PiPr₃)(SbiPr₃)] ( 10 ) und triisopropylarsane. The molecular structure of 5 was determined by X‐ray crystallography.     

Syntheses and Characterization of Samarium and Erbium Borohydrido Complexes Supported by N‐Aryliminopyrrole Ligand

Reaction of potassium salt of N‐aryliminopyrrole ligand [2‐(2, 6‐iPr₂C₆H₃N=CH)–C₄H₃NK] ( 1 ) with samarium tris‐boro‐hydride [Sm(BH₄)₃(THF)₃] gave a samarium ate complex [η²‐{2‐(2, 6‐iPr₂C₆H₃N=CH)–C₄H₃N}₃Sm(η¹‐BH₄){K(THF)₆] ( 2 ); whereas similar treatment with erbium borohydride [Er(BH₄)₃(THF)₃] afforded the mono(iminopyrrolyl) complex [η²‐{2‐(2, 6‐iPr₂C₆H₃N=CH)–C₄H₃N}Er(η³‐BH₄)₂(THF)₂] ( 3 ). In the solid‐state structures, the samarium complex 2 shows a rarely observed η¹ and the erbium complex 3 shows a usual η³ coordination mode of the borohydrido ligand.     

Der Dihydridoiridium(III)‐Komplex [IrH2Cl(PiPr3)2] als Molekülbaustein für unsymmetrische Rhodium–Iridiumund Iridium–Iridium‐Zweikernverbindungen

The Dihydridoiridium(III) Complex [IrH₂Cl(P i Pr₃)₂] as a Molecular Building Block for Unsymmetrical Binuclear Rhodium–Iridium and Iridium–Iridium Compounds The title compound [IrH₂Cl(PiPr₃)₂] ( 3 ) reacts with the chloro‐bridged dimers [RhCl(PiPr₃)₂]₂ ( 1 ) and [IrCl(C₈H₁₄)(PiPr₃)]₂ ( 5 ) by cleavage of the Cl‐bridges to give the unsymmetrical binuclear complexes 4 and 6 with Rh(μ‐Cl)₂Ir and Ir(μ‐Cl)₂Ir as the central building block. The reactions of 3 with the bis(cyclooctene) and (1,5‐cyclooctadiene) compounds [MCl(C₈H₁₄)₂]₂ ( 7 , 8 ) and [MCl(η⁴‐C₈H₁₂)]₂ ( 9 , 10 ) (M = Rh, Ir) occur analogously and afford the rhodium(I)‐iridium(III) and iridium(I)‐iridium(III) complexes 11 – 14 in 70–80% yield. Treatment of [(η⁴‐C₈H₁₂)M(μ‐Cl)₂IrH₂(PiPr₃)₂] ( 13 , 14 ) with phenylacetylene leads to the formation of the substitution products [(η⁴‐C₈H₁₂)M(μ‐Cl)₂IrH(C≡CPh)(PiPr₃)₂] ( 15 , 16 ) without changing the central molecular core. Similarly, the compound [(η⁴‐C₈H₁₂)Rh(μ‐Br)₂IrH(C≡CPh)(PiPr₃)₂] ( 18 ) has been prepared; it was characterized by X‐ray crystallography.     

A Nickel Complex Containing a Pyramidalized,Ambiphilic Pincer Germylene Ligand

Reaction of N-heterocyclic carbene (NHC)-stabilized PGeP-type germylene Ge{o-(PiPr₂)C₆H₄}₂⋅^MeIiPr ( 1 ) (^MeIiPr=1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) with Ni(cod)₂ gave pincer germylene complex Ni[Ge{o-(PiPr₂)C₆H₄}₂](^MeIiPr) ( 2 ), in which the Ge center of 2 is significantly pyramidalized. Theoretical calculation on 2 predicted the ambiphilicity of the germanium center, which was confirmed by reactivity studies. Thus, complex 2 reacted with both Lewis base ^MeIMe (^MeIMe=1,3,4,5-tetramethylimidazol-2-ylidene) and Lewis acid BH₃⋅SMe₂ at the germanium center to afford the adducts Ni[Ge{o-(PiPr₂)C₆H₄}₂⋅^MeIMe](^MeIiPr) ( 3 ) and Ni[Ge{o-(PiPr₂)C₆H₄}₂⋅BH₃](^MeIiPr) ( 4 ), respectively. Furthermore, the former was slowly converted to dinuclear complex Ni₂[Ge{o-(PiPr₂)C₆H₄}₂]₂(^MeIMe)₂ ( 5 ) at room temperature. Complex 5 can be regarded as a dimer of the ^MeIMe analog of 2 with a Ni-Ge-Ge-Ni linkage.     

Synthese,Struktur und Photochemie von Olefiniridium(I)‐Komplexen mit Acetylacetonatoliganden

Synthesis, Structure, and Photochemical Behavior of Olefine Iridium(I) Complexes with Acetylacetonato Ligands The bis(ethene) complex [Ir(κ²‐acac)(C₂H₄)₂] ( 1 ) reacts with tertiary phosphanes to give the monosubstitution products [Ir(κ²‐acac)(C₂H₄)(PR₃)] ( 2 – 5 ). While 2 (R = iPr) is inert toward PiPr₃, the reaction of 2 with diphenylacetylene affords the π‐alkyne complex [Ir(κ²‐acac)(C₂Ph₂)(PiPr₃)] ( 6 ). Treatment of [IrCl(C₂H₄)₄] with C‐functionalized acetylacetonates yields the compounds [Ir(κ²‐acacR^1,2)(C₂H₄)₂] ( 8 , 9 ), which react with PiPr₃ to give [Ir(κ²‐acacR^1,2)(C₂H₄)(PiPr₃)] ( 10 , 11 ) by displacement of one ethene ligand. UV irradiation of 5 (PR₃ = iPr₂PCH₂CO₂Me) and 11 (R² = (CH₂)₃CO₂Me) leads, after addition of PiPr₃, to the formation of the hydrido(vinyl)iridium(III) complexes 7 and 12 . The reaction of 2 with the ethene derivatives CH₂=CHR (R = CN, OC(O)Me, C(O)Me) affords the compounds [Ir(κ²‐acac)(CH₂=CHR)(PiPr₃)] ( 13 – 15 ), which on photolysis in the presence of PiPr₃ also undergo an intramolecular C–H activation. In contrast, the analogous complexes [Ir(κ²‐acac)(olefin)(PiPr₃)] (olefin = (E)‐C₂H₂(CO₂Me)₂ 16 , (Z)‐C₂H₂(CO₂Me)₂ 17 ) are photochemically inert.     

Isomorphous rare‐earth tris[bis(2,6‐diisopropylphenyl) phosphate] complexes and their catalytic properties in 1,3‐diene polymerization and in the inhibited oxidation of polydimethylsiloxane

Crystals of mononuclear tris[bis(2,6‐diisopropylphenyl) phosphato‐κO]pentakis(methanol‐κO)lanthanide methanol monosolvates of lanthanum, [La(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 1 ), cerium, [Ce(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 2 ), and neodymium, [Nd(C₂₄H₃₄O₄P)₃(CH₃OH)₅]·CH₃OH, ( 3 ), have been obtained by reactions between LnCl₃(H₂O)_n (n = 6 or 7) and lithium bis(2,6‐diisopropylphenyl) phosphate in a 1:3 molar ratio in methanol media. Compounds ( 1 )–( 3 ) crystallize in the monoclinic P2₁/c space group and have isomorphous crystal structures. All three bis(2,6‐diisopropylphenyl) phosphate ligands display a κO‐monodentate coordination mode. The coordination number of the metal atom is 8. Each [Ln{O₂P(O‐2,6‐ⁱPr₂C₆H₃)₂}₃(CH₃OH)₅] molecular unit exhibits four intramolecular O—H…O hydrogen bonds, forming six‐membered rings. The unit forms two intermolecular O—H…O hydrogen bonds with one noncoordinating methanol molecule. All six hydroxy H atoms are involved in hydrogen bonding within the [Ln{O₂P(O‐2,6‐ⁱPr₂C₆H₃)₂}₃(CH₃OH)₅]·CH₃OH unit. This, along with the high steric hindrance induced by the three bulky diaryl phosphate ligands, prevents the formation of a hydrogen‐bond network. Complexes ( 1 )–( 3 ) exhibit disorder of two of the isopropyl groups of the phosphate ligands. The cerium compound ( 2 ) demonstrates an essential catalytic inhibition in the thermal decomposition of polydimethylsiloxane in air at 573 K. Catalytic systems based on the neodymium complex tris[bis(2,6‐diisopropylphenyl) phosphato‐κO]neodymium, ( 3′ ), which was obtained as a dry powder of ( 3 ) upon removal of methanol, display a high catalytic activity in isoprene and butadiene polymerization.     

Accessing Cationic α-Silylated and α-Germylated Phosphorus Ylides

The synthesis and full characterization of α-silylated (α-SiCPs; 1 – 7 ) and α-germylated (α-GeCPs; 11 – 13 ) phosphorus ylides bearing one chloride substituent R₃PC(R¹)E(Cl)R²₂ (R=Ph; R¹=Me, Et, Ph; R²=Me, Et, iPr, Mes; E=Si, Ge) is presented. The molecular structures were determined by X-ray diffraction studies. The title compounds were applied in halide abstraction studies in order to access cationic species. The reaction of Ph₃PC(Me)Si(Cl)Me₂ ( 1 ) with Na[B(C₆F₅)₄] furnished the dimeric phosphonium-like dication [Ph₃PC(Me)SiMe₂]₂[B(C₆F₅)₄]₂ ( 8 ). The highly reactive, mesityl- or iPr-substituted cationic species [Ph₃PC(Me)SiMes₂][B(C₆F₅)₄] ( 9 ) and [Ph₃PC(Et)SiiPr₂][B(C₆F₅)₄] ( 10 ) could be characterized by NMR spectroscopy. Carrying out the halide abstraction reaction in the sterically demanding ether iPr₂O afforded the protonated α-SiCP [Ph₃PCH(Et)Si(Cl)iPr₂][B(C₆F₅)₄] ( 6 dec ) by sodium-mediated basic ether decomposition, whereas successfully synthesized [Ph₃PC(Et)SiiPr₂][B(C₆F₅)₄] ( 10 ) readily cleaves the F−C bond in fluorobenzene. Thus, the ambiphilic character of α-SiCPs is clearly demonstrated. The less reactive germanium analogue [Ph₃PC(Me)GeMes₂][B{3,5-(CF₃)₂C₆H₃}₄] ( 14 ) was obtained by treating 11 with Na[B{3,5-(CF₃)₂C₆H₃}₄] and fully characterized including by X-ray diffraction analysis. Structural parameters indicate a strong C_Ylide−Ge interaction with high double bond character, and consequently the C−E (E=Si, Ge) bonds in 9 , 10 and 14 were analyzed with NBO and AIM methods.     

Reactivity of Cationic Agostic and Carbene Structures Derived from Platinum(II) Metallacycles

This paper describes the formation of new platinacyclic complexes derived from the phosphine ligands PiPr₂Xyl, PMeXyl₂, and PMe₂Ar (Xyl=2,6‐Me₂C₆H₃ and Ar=2,6‐(2,6‐Me₂C₆H₃)₂‐C₆H₃) as well as reactivity studies of the trans‐[Pt(C^P)₂] bis‐metallacyclic complex 1 a derived from PiPr₂Xyl. Protonation of compound 1 a with [H(OEt₂)₂][BAr_F] (BAr_F=B[3,5‐(CF₃)₂C₆H₃]₄) forms a cationic δ‐agostic structure 4 a , whereas α‐hydride abstraction employing [Ph₃C][PF₆] produces a cationic platinum carbene trans‐[Pt{PiPr₂(2,6‐CH(Me)C₆H₃}{PiPr₂(2,6‐CH₂(Me)C₆H₃}][PF₆] ( 8 ). Compounds 4 a and 8 react with H₂ to yield the same 1:3 equilibrium mixture of 4 a and trans‐[PtH(PiPr₂Xyl)₂][BAr_F] ( 6 ), in which one of the phosphine ligands participates in a δ‐agostic interaction. DFT calculations reveal that H₂ activation by 8 occurs at the highly electrophilic alkylidene terminus with no participation of the metal. The two compounds 4 a and 8 experience C–C coupling reactions of a different nature. Thus, 4 a gives rise to complex trans‐[PtH{(E)‐1,2‐bis(2‐(PiPr₂)‐3‐MeC₆H₃)CH?CH}] ( 7 ) that contains a tridentate diphosphine–alkene ligand, through agostic C?H oxidative cleavage and C–C reductive coupling steps, whereas the C–C coupling reaction in 8 involves classical migratory insertion of its [Pt?CH] and [Pt?CH₂] bonds promoted by platinum coordination of CO or CNXyl. The mechanisms of the C?C bond‐forming reactions have also been investigated by computational methods.     

Neue Kupferkomplexe mit Phosphaalkenliganden. Molekülstruktur von [Cu{P(Mes*)C(NMe2)2}2]BF4 (Mes* = 2,4,6‐tBu3C6H2)

New Copper Complexes Containing Phosphaalkene Ligands. Molecular Structure of [Cu{P(Mes*)C(NMe₂)₂}₂]BF₄ (Mes* = 2,4,6‐tBu₃C₆H₂) Reaction of equimolar amounts of the inversely polarized phosphaalkene tBuP=C(NMe₂)₂ ( 1a ) and copper(I) bromide or copper(I) iodide, respectively, affords complexes [Cu₃X₃{μ‐P(tBu)C(NMe₂)₂}₃] ( 2 ) (X =Br) and ( 3 ) (X = I) as the formal result of the cyclotrimerization of a 1:1‐adduct. Treatment of 1a with [Cu(L)Cl] (L = PiPr₃; SbiPr₃) leads to the formation of compounds [CuCl(L){P(tBu)C(NMe₂)₂}] ( 4a ) (L = PiPr₃) and ( 4b ) (L = SbiPr₃), respectively. Reaction of [(MeCN)₄Cu]BF₄ with two equivalents of PhP=C(NMe₂)₂ ( 1b ) yields complex [Cu{P(Ph)C(NMe₂)₂}₂]BF₄ ( 5b ). Similarly, compounds [Cu{P(Aryl)C(NMe₂)₂}₂]BF₄ ( 5c (Aryl = Mes and 5d (Aryl = Mes*)) are obtained from ArylP=C(NMe₂)₂ ( 1c : Aryl = Mes; 1d : Mes*) and [(MeCN)₄Cu]BF₄ in the presence of SbiPr₃. Complexes 2 , 3 , 4a , 4b , and 5b‐5d are characterized by means of elemental analyses and spectroscopy (¹H‐, ¹³C{¹H}‐, ³¹P{¹H}‐NMR). The molecular structure of 5d is determined by X‐ray diffraction analysis.     

cis‐Tetracarbonylbis(tricyclohexyl­phosphine)molybdenum(0) and pentacarbonyl(tricyclohexylphos­phine)molybdenum(0)

In the present redetermination of the complex cis‐tetra­carbonyl­bis­(tri­cyclo­hexyl­phosphine)molybdenum(0), (I), [Mo(C₁₈H₃₃P)₂(CO)₄] or cis‐{η¹‐[P(C₆H₁₁)₃]₂}Mo(CO)₄, the Mo atom has a distorted octahedral geometry with a large P—Mo—P angle of 104.8 (1)°. A strong trans influence on the carbonyls in (I) is seen in a shortening of the Mo—C and a lengthening of the C—O distances opposite the phosphines compared with those that are cis. This influence is greatly diminished in the complex penta­carbonyl­(tri­cyclo­hexyl­phosphine)­molyb­denum(0), (II), [Mo(C₁₈H₃₃P)(CO)₅] or {η¹‐[P(C₆H₁₁)₃]}­Mo(CO)₅, the core of which has a slightly distorted C_4v geometry.     

The First [4+2]‐Coordinated Tetraorganolead Compound: Synthesis,Structure and Conversion into a Triorganolead Cation,a Benzoxaphosphaplumbole,and Diorganolead Dihalides

The syntheses and molecular structures, as determined by single‐crystal X‐ray diffraction analysis, of the first intramolecularly [4+2]‐coordinated tetraorganolead compound {4‐t‐Bu‐2, 6‐[P(O)(OEt)₂]₂C₆H₂}PbPh₃ ( 2 ) and the triphenyllead chloride adduct of the first intramolecularly coordinated benzoxaphosphaplumbole {[1(Pb), 3(P)‐Pb(Ph)₂OP(O)(OEt)‐5‐t‐Bu‐7‐P(O)(OEt)₂]C₆H₂·Ph₃PbCl} ( 3a ) are reported. The reaction of 2 with [Ph₃C]⁺ [PF₆]^— and p‐MeC₆H₄SO₃H, respectively, provides the triorganolead salts {4‐t‐Bu‐2, 6‐[P(O)(OEt)₂]₂C₆H₂}PbPh₂⁺X^— ( 4 , X = PF₆; 4a , X = p‐MeC₆H₄SO₃). Reaction of 2 with bromine and hydrogen chloride, respectively, gives the diorganolead dihalides {4‐t‐Bu‐2, 6‐[P(O)(OEt)₂]₂C₆H₂}PbPhX₂ ( 5 , X = Br; 6 , X = Cl).     

Remote Multiproton Storage within a Pyrrolide‐Pincer‐Type Ligand

A chemically non‐innocent pyrrole‐based trianionic (ONO)^3? pincer ligand within [(pyr‐ONO)TiCl(thf)₂] ( 2 ) can access the dianionic [(3H‐pyr‐ONO)TiCl₂(thf)] ( 1‐THF ) and monoanionic [(3H,4H‐pyr‐ONO)TiCl₂(OEt₂)][B{3,5‐(CF₃)₂C₆H₃}₄] ( 3‐Et₂O ) states through remote protonation of the pyrrole γ‐C π‐bonds. The homoleptic [(3H‐pyr‐ONO)₂Zr] ( 4 ) was synthesized and characterized by X‐ray diffraction and NMR spectroscopy in solution. The protonation of 4 by [H(OEt₂)₂][B{C₆H₃(CF₃)₂}₄] yields [(3H,4H‐pyr‐ONO)(3H‐pyr‐ONO)Zr][B{3,5‐(CF₃)₂C₆H₃}₄] ( 5 ), thus demonstrating the storage of three protons.     

Über einige ein‐ und zweikernige Hydroxoiridium(I)‐Komplexe

Some mono‐ and dinuclear Hydroxoiridium(I) Complexes The chloro‐bridged iridium(I) compound [Ir₂(μ‐Cl)₂(C₈H₁₄)₄] ( 1 ) reacts in the biphasic system benzene/water with KOH in the presence of [NEt₃(CH₂Ph)]Cl (TEBA) to give the corresponding dinuclear complex [Ir₂(μ‐OH)₂(C₈H₁₄)₄] ( 2 ). Stepwise substitution of the cyclooctene ligands by PiPr₃ and ethene affords via the intermediate [Ir₂(μ‐OH)₂(C₈H₁₄)₂(PiPr₃)₂] (isolated as a mixture of isomers 3 a , b ) the product [Ir₂(μ‐OH)₂(C₂H₄)₂(PiPr₃)₂] ( 4 ) in excellent yield. Reaction of 4 with PiPr₃in the molar ratio of 1:2 leads to the formation of the mononuclear compound trans‐[Ir(OH)(C₂H₄)(PiPr₃)₂] ( 5 ), the ethene ligand of which cannot be replaced by CPh₂ upon treatment with Ph₂CN₂.     

Synthese und Metallierung des Diaminosiloxans O(SiiPr2NH2)2

Synthesis and Metalation of the Diaminosiloxane O(SiiPr₂NH₂)₂ The 1,3‐diaminoldisiloxane O(SiiPr₂NH₂)₂ ( 1 ) was obtained from the reaction of O(SiiPr₂Cl)₂ with NH₃. The reactions of 1 with AlEt₃ or GaEt₃ produced the compounds [O{SiiPr₂N(H)MEt₂}{SiiPr₂NMEt}]₂ ( 2 : M = Al; 3 : M = Ga). The crystal structures of 2 and 3 were determined by single crystal X‐ray diffraction, showing a polycyclic M₄N₄Si₄O₂ core structure of these molecules.     

Dinuclear neodymium and lanthanum bis(2,6‐diisopropylphenyl) phosphate complexes bearing a hydroxide ligand: catalytic activity of the Nd complex in 1,3‐diene polymerization

The reactions of K[(2,6‐ⁱPr₂C₆H₃‐O)₂POO] either with LaCl₃(H₂O)₇ or with Nd(NO₃)₃(H₂O)₆ in a 3:1 molar ratio, followed by vacuum drying and recrystallization from alkanes, have led to the formation of diaquapentakis[bis(2,6‐diisopropylphenyl) phosphato]‐μ‐hydroxido‐dilanthanum hexane disolvate, [La₂(C₂₄H₃₄O₄P)₅(OH)(H₂O)₂]·2C₆H₁₄, ( 1 )·2(hexane), and tetraaquatetrakis[bis(2,6‐diisopropylphenyl) phosphato]‐μ‐hydroxido‐dineodymium bis(2,6‐diisopropylphenyl) phosphate heptane disolvate, [Nd₂(C₂₄H₃₄O₄P)₄(OH)(H₂O)₄]·2C₆H₁₄, ( 2 )·2(heptane). The compounds crystalize in the P2₁/n and P space groups, respectively. The diaryl‐substituted organophosphate ligand exhibits three different coordination modes, viz. κ²O,O′‐terminal [in ( 1 ) and ( 2 )], κO‐terminal [in ( 1 )] and μ₂‐κ¹O:κ¹O′‐bridging [in ( 1 ) and ( 2 )]. Binuclear structures ( 1 ) and ( 2 ) are similar and have the same unique Ln₂(μ‐OH)(μ‐OPO)₂ core. The structure of ( 2 ) consists of an [Nd₂{(2,6‐ⁱPr₂C₆H₃‐O)₂POO}₄(OH)(H₂O)₄]⁺ cation and a [(2,6‐ⁱPr₂C₆H₃‐O)₂POO]⁻ anion, which are bound via four intermolecular O—H…O hydrogen bonds. The molecular structure of ( 1 ) displays two O—H…O hydrogen bonds between OH/H₂O ligands and a κ¹O‐terminal organophosphate ligand, which resembles, to some extent, the `free' [(2,6‐ⁱPr₂C₆H₃‐O)₂POO]⁻ anion in ( 2 ). NMR studies have shown that the formation of ( 1 ) undoubtedly occurs due to intramolecular hydrolysis during vacuum drying of the aqueous La tris(phosphate) complex. Catalytic experiments have demonstrated that the presence of the coordinated hydroxide anion and water molecules in precatalyst ( 2 ) substantially lowered the catalytic activity of the system prepared from ( 2 ) in butadiene and isoprene polymerization compared to the catalytic system based on the neodymium tris[bis(2,6‐diisopropylphenyl) phosphate] complex, which contains neither OH nor H₂O ligands.     

Reaction of the Pincer‐type Ligand {2, 6‐[P(O)(OEt)2]2‐4‐tert‐Bu‐C6H2}— with [Ph3C]+[PF6]—. Unprecedented Rearrangement and Carbon‐Carbon Bond Formation

The reaction of the organolithium derivative {2, 6‐[P(O)(OEt)₂]₂‐4‐tert‐Bu‐C₆H₂}Li ( 1 ‐Li) with [Ph₃C]⁺[PF₆]^— gave the substituted biphenyl derivative 4‐[(C₆H₅)₂CH]‐4′‐[tert‐Bu]‐2′, 6′‐[P(O)(OEt)₂]₂‐1, 1′‐biphenyl ( 5 ) which was characterized by ¹H, ¹³C and ³¹P NMR spectroscopy and single crystal X‐ray analysis. Ab initio MO‐calculations reveal the intramolecular O···C distances in 5 of 2.952(4) and 2.988(5)Å being shorter than the sum of the van der Waals radii of oxygen and carbon to be the result of crystal packing effects. Also reported are the synthesis and structure of the bromine‐substituted derivative {2, 6‐[P(O)(OEt)₂]₂‐4‐tert‐Bu]C₆H₂}Br ( 9 ) and the structure of the protonated ligand 5‐tert‐Bu‐1, 3‐[P(O)(OEt)₂]₂C₆H₃ ( 1 ‐H). The structures of 1 ‐H, 5 , and 9 are compared with those of related metal‐substituted derivatives.