Ein‐ und zweikernige Rhodiumkomplexe mit Arsino(phosphino)methanen in unterschiedlichen Koordinationsformen

Mono‐ and Dinuclear Rhodium Complexes with Arsino(phosphino)methanes in Different Coordination Modes The cyclooctadiene complex [Rh(η⁴‐C₈H₁₂)(κ²‐tBu₂AsCH₂PiPr₂)](PF₆) ( 1a ) reacts with CO and CNtBu to give the substitution products [Rh(L)₂(κ²‐tBu₂AsCH₂PiPr₂)](PF₆) ( 2 , 3 ). From 1a and Na(acac) in the presence of CO the neutral compound [Rh(κ²‐acac)(CO)(κ‐P‐tBu₂AsCH₂PiPr₂)] ( 4 ) is formed. The reactions of 1a , the corresponding B(Ar_F)₄‐salt 1b and [Rh(η⁴‐C₈H₁₂)(κ²‐iPr₂AsCH₂PiPr₂)](PF₆) ( 5 ) with acetonitrile under a H₂ atmosphere affords the complexes [Rh(CH₃CN)₂(κ²‐R₂AsCH₂PiPr₂)]X ( 6a , 6b , 7 ), of which 6a (R = tBu; X = PF₆) gives upon treatment with Na(acac‐f₆) the bis(chelate) compound [Rh(κ²‐acac‐f₆)(κ²‐tBu₂AsCH₂PiPr₂)] ( 8 ). From 8 and CH₃I a mixture of two stereoisomers of composition [Rh(CH₃)I(κ²‐acac‐f₆)(κ²‐tBu₂AsCH₂PiPr₂)] ( 9/10 ) is generated by oxidative addition, and the molecular structure of the racemate 9 has been determined. The reactions of 1a and 5 with CO in the presence of NaCl leads to the formation of the “A‐frame” complexes [Rh₂(CO)₂(μ‐Cl)(μ‐R₂AsCH₂PiPr₂)₂](PF₆) ( 11 , 12 ), which have been characterized crystallographically. From 11 and 12 the dinuclear substitution products [Rh₂(CO)₂(μ‐X)(μ‐R₂AsCH₂PiPr₂)₂](PF₆) ( 13 ‐ 16 ) are obtained by replacing the bridging chloride for bromide, hydride or hydroxide, respectively. While 12 (R = iPr) reacts with NaI to give the related “A‐frame” complex 18 , treatment of 11 (R = tBu) with NaI yields the mononuclear chelate compound [RhI(CO)(κ²‐tBu₂AsCH₂PiPr₂)] ( 20 ). The reaction of 20 with CH₃I affords the acetyl complex [RhI₂{C(O)CH₃}(κ²‐tBu₂AsCH₂PiPr₂)] ( 21 ) with five‐coordinate rhodium atom.     

Homolytic C−H Bond Activation by Phosphine−Quinone-Based Radical Ion Pairs

Herein, we present the formation of transient radical ion pairs (RIPs) by single-electron transfer (SET) in phosphine−quinone systems and explore their potential for the activation of C−H bonds. PMes₃ (Mes=2,4,6-Me₃C₆H₂) reacts with DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone) with formation of the P−O bonded zwitterionic adduct Mes₃P−DDQ ( 1 ), while the reaction with the sterically more crowded PTip₃ (Tip=2,4,6-iPr₃C₆H₂) afforded C−H bond activation product Tip₂P(H)(2-[CMe₂(DDQ)]-4,6-iPr₂-C₆H₂) ( 2 ). UV/Vis and EPR spectroscopic studies showed that the latter reaction proceeds via initial SET, forming RIP [PTip₃]⋅⁺[DDQ]⋅⁻, and subsequent homolytic C−H bond activation, which was supported by DFT calculations. The isolation of analogous products, Tip₂P(H)(2-[CMe₂{TCQ−B(C₆F₅)₃}]-4,6-iPr₂-C₆H₂) ( 4 , TCQ=tetrachloro-1,4-benzoquinone) and Tip₂P(H)(2-[CMe₂{oQ^tBu−B(C₆F₅)₃}]-4,6-iPr₂-C₆H₂) ( 8 , oQ^tBu=3,5-di-tert-butyl-1,2-benzoquinone), from reactions of PTip₃ with Lewis-acid activated quinones, TCQ−B(C₆F₅)₃ and oQ^tBu−B(C₆F₅)₃, respectively, further supports the proposed radical mechanism. As such, this study presents key mechanistic insights into the homolytic C−H bond activation by the synergistic action of radical ion pairs.     

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.     

Hexakis(2,4,6‐triisopropylphenyl)cyclotristannoxane – a Molecular Diorganotin Oxide with Kinetically Inert Sn–O Bonds

The single‐crystal X‐ray structure analysis of hexakis(2,4,6‐triisopropylphenyl)cyclotristannoxane, cyclo‐[(2,4,6‐i‐Pr₃‐C₆H₂)₂SnO]₃ ( 1 ), is reported and reveals this compound to contain an almost planar six‐membered ring. Redistribution reactions of 1 with cyclo‐(t‐Bu₂SnO)₃ and t‐Bu₂SiCl₂, respectively, failed and indicate an unusual kinetic inertness of the Sn–O bonds in 1 as compared to related molecular diorganotin oxides containing less bulkier substituents. The redistribution reaction of cyclo‐(t‐Bu₂SnO)₃ with cyclo‐(t‐Bu₂SnS)₂ leads to an equilibrium involving the trimeric diorganotin oxysulphides cyclo‐t‐Bu₂Sn(OSnt‐Bu₂)₂S ( 2 a ) and cyclo‐t‐Bu₂Sn(SSnt‐Bu₂)₂O ( 2 b ).     

Charge Effects in PCP Pincer Complexes of NiII bearing Phosphinite and Imidazol(i)ophosphine Coordinating Jaws: From Synthesis to Catalysis through Bonding Analysis

This contribution reports on a new family of Ni^II pincer complexes featuring phosphinite and functional imidazolyl arms. The proligands ^RPIMC^HOP^R′ react at room temperature with Ni^II precursors to give the corresponding complexes [(^RPIMCOP^R′)NiBr], where ^RPIMCOP^R=κ^P,κ^C,κ^P‐{2‐(R′₂PO),6‐(R₂PC₃H₂N₂)C₆H₃}, R=iPr, R′=iPr ( 3 b , 84 %) or Ph ( 3 c , 45 %). Selective N‐methylation of the imidazole imine moiety in 3 b by MeOTf (OTf=OSO₂CF₃) gave the corresponding imidazoliophosphine [(^iPrPIMIOCOP^iPr)NiBr][OTf], 4 b , in 89 % yield (^iPrPIMIOCOP^iPr=κ^P,κ^C,κ^P‐{2‐(iPr₂PO),6‐(iPr₂PC₄H₅N₂)C₆H₃}). Treating 4 b with NaOEt led to the NHC derivative [(NHCCOP^iPr)NiBr], 5 b , in 47 % yield (NHCCOP^iPr=κ^P,κ^C,κ^C‐{2‐(iPr₂PO),6‐(C₄H₅N₂)C₆H₃)}). The bromo derivatives 3–5 were then treated with AgOTf in acetonitrile to give the corresponding cationic species [(^RPIMCOP^R)Ni(MeCN)][OTf] [R=Ph, 6 a (89 %) or iPr, 6 b (90 %)], [(^RPIMIOCOP^R)Ni(MeCN)][OTf]₂ [R=Ph, 7 a (79 %) or iPr, 7 b (88 %)], and [(NHCCOP^R)Ni(MeCN)][OTf] [R=Ph, 8 a (85 %) or iPr, 8 b (84 %)]. All new complexes have been characterized by NMR and IR spectroscopy, whereas 3 b , 3 c , 5 b , 6 b , and 8 a were also subjected to X‐ray diffraction studies. The acetonitrile adducts 6 – 8 were further studied by using various theoretical analysis tools. In the presence of excess nitrile and amine, the cationic acetonitrile adducts 6 – 8 catalyze hydroamination of nitriles to give unsymmetrical amidines with catalytic turnover numbers of up to 95.     

Formation and Reactivity of an Aluminabenzene Ligand at Pentadienyl‐Supported Rare‐Earth Metals

The half‐open rare‐earth‐metal aluminabenzene complexes [(1‐Me‐3,5‐tBu₂‐C₅H₃Al)(μ‐Me)Ln(2,4‐dtbp)] (Ln=Y, Lu) are accessible via a salt metathesis reaction employing Ln(AlMe₄)₃ and K(2,4‐dtbp). Treatment of the yttrium complex with B(C₆F₅)₃ and tBuCCH gives access to the pentafluorophenylalane complex [{1‐(C₆F₅)‐3,5‐tBu₂‐C₅H₃Al}{μ‐C₆F₅}Y{2,4‐dtbp}] and the mixed vinyl acetylide complex [(2,4‐dtbp)Y(μ‐η¹:η³‐2,4‐tBu₂‐C₅H₄)(μ‐CCtBu)AlMe₂], respectively.     

Synthesis and X-ray crystal structures of [Ph2PMe2][(η-C5H4Bu)2Li] and [(η-C5H4Bu)2Yb(Cl)CH2P(Me)Ph2]

The interaction of [(η⁵-C₅H₄Bu^t)₂YbCl · LiCl] with one equivalent of Li[(CH₂) (CH₂)PPh₂] in tetrahydrofuran gave [Ph₂PMe₂][(η⁵-C₅H₄Bu^t)₂Li] (1) and [(η⁵-C₅H₄Bu^t)₂Yb(Cl)CH₂P(Me)Ph₂] (2) in 10% and 30% yields, respectively. 1 could also be prepared in 70% yield from the reaction of [Ph₂PMe₂][CF₃SO₃] with two equivalents of (C₅H₄Bu^t)Li. Both compounds have been fully characterized by analytical, spectroscopic and X-ray diffraction methods. The solid state structure of 1 reveals a sandwich structure for the [(η⁵-C₅H₄Bu^t)₂Li]⁻ anion.     

The Synthesis of tert‐Butyl(dichloromethyl)bis(trimethylsilyl)silane and (Dibromomethyl)ditert‐butyl(trimethylsilyl)silane and their Reactions with Organolithium Derivatives

tert‐Butyl(dichloromethyl)bis(trimethylsilyl)silane ( 4 ), prepared by the reaction of tert‐butylbis(trimethylsilyl)silane with trichloromethane and potassium tert‐butoxide, reacted with 2,4,6‐triisopropylphenyllithium (TipLi) (molar ratio 1 : 2) at room temperature to give (after hydrolytic workup) the silanol tBu(2,4,6‐iPr₃C₆H₂)Si(OH)–CH(SiMe₃)₂ ( 15 ). The formation of 15 is discussed as proceeding through the indefinitely stable silene tBu(2,4,6‐iPr₃C₆H₂)Si=C(SiMe₃)₂ ( 13 ), but attempts to isolate the compound failed. Treatment of (dibromomethyl)ditert‐butyl(trimethylsilyl)silane ( 7 ), made from tBu₂(Me₃Si)SiH, HCBr₃ and KOtBu, with methyllithium (1 : 3) at –78 °C afforded tBu₂MeSi–CHMeSiMe₃ ( 19 ); 7 and phenyllithium (1 : 3) under similar conditions gave tBu₂PhSi–CH₂SiMe₃ ( 20 ). The reaction paths leading to 15 , 19 and 20 are discussed. Reduction of 7 with lithium in THF produced the substituted ethylene tBu₂(Me₃Si)SiCH=CHSitBu₂SiMe₃ ( 21 ). For 21 the results of an X‐ray structural analysis are given.     

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.     

Facile synthesis of zwitterionic organoaluminum complexes containing formally dianionic homoscorpionate ligands

A series of zwitterionic aluminum complexes of the type AlX[(2‐O‐3,5‐tBu₂C₆H₂)₃PZ] (AlX [O₃PZ]; X = Cl, Me, Et, and iBu; Z = H, Me) containing C₃‐symmetric, formally dianionic, facially tridentate ligands [O₃PZ]^2? were prepared and structurally characterized. Although serendipitous, these complexes can be readily synthesized by partial protonolysis of AlX₃ with equal molar (2‐HO‐3,5‐tBu₂C₆H₂)₃P (H₃[O₃P]) or [(2‐HO‐3,5‐tBu₂C₆H₂)₃p.m.e](OTf) ({H₃[O₃PMe]}OTf) in THF at 25°C or elevated temperatures. Alcoholysis of AlMe[O₃PMe] ( 2 ) with an excess amount of MeOH in refluxing toluene generates AlOMe[O₃PMe] ( 10 ). Salt metathesis of AlCl[O₃PMe] ( 6 ) with nBuM (M = Li, MgCl) and NaOR (R = tBu, Ph) in ethereal solutions affords AlnBu[O₃PMe] ( 9 ) and AlOR[O₃PMe] (R = tBu ( 11 ), Ph ( 12 )), respectively. Reactivity of 10 , 11 , and 12 with respect to catalytic ring‐opening polymerization of ε‐caprolactone is assessed.     

Verbindungen des Germainums und Zinns. 17. Alkylarylstannylen-Komplexe des Chroms und Molybdäns ohne Donorstabilisierung

Compounds of Germanium and Tin. 17 [1]. Alkylarylstannylene Complexes of Chromium and Molybdenum without Donor Stabilization Reaction of the complexes [(OC)₅M(THF)], M = Cr, Mo, with the alkylarylstannylene RR′Sn: R = 2,4,6-tBu₃C₆H₂, R′ = CH₂C(CH₃)₂-3,5-tBu₂C₆H₂, provides the donor-free stannylene complexes [(OC)₅Cr?SnRR′] ( 6 ) and [(OC)₅Mo?SnRR′] ( 8 ), respectively. The X-ray structure analyses of the isotypic compounds 6 and 8 reveal the three coordinate tin atoms in strictly planar environments and acute CSnC angles of 91.2° ( 6 ) and 91.3° ( 8 ).     

Die Struktur von [Li(tmeda)2][Zn(2,4,6-i-Pr3C6H2)3]

X-Ray Structure of [Li(tmeda)₂][Zn(2,4,6- i Pr₃C₆H₂)₃] A side reaction of zinc halide containing VCl₂(tmeda)₂ and Li(2,4,6-iPr₃C₆H₂) formed [Li(tmeda)₂][Zn(2,4,6-iPr₃C₆H₂)₃] · 0,5[(tmeda)Li(μ-Cl)]₂. The crystal structure (orthorhombic, Pbca, a = 26,226(2), b = 19,739(2), c = 27,223(5) Å, Z = 8, R = 0,062, wR² = 0,154) contains trigonal planar zinc anions with Zn–C distances of 2,039(7) Å (average) and a propeller like arrangement of the aryl rings.     

Lanthanide borohydrido complexes for MMA polymerization: syndio‐ vs iso‐ stereocontrol

This paper presents an extensive study of the polymerization of MMA with borohydrido lanthanide complexes for the first time. Catalytic systems are made from a lanthanide derivative bearing zero one, or two bulky ligands: substituted cyclopentadienyl (Cp^*′ = C₅Me₄nPr, Cp⁴ⁱ = C₅HiPr₄, Cp^Ph3 = H₂C₅Ph₃‐1,2,4), and/or diketiminate ([(p‐tol)NN] = [(p‐CH₃C₆H₄)N(CH₃)C]₂CH), in the presence of variable quantities of alkylating agent. With BuLi in apolar medium, highly isotactic polymer (up to 95.6%) is formed. In THF, syndiotactic‐rich PMMA is obtained whatever the nature of the co‐catalyst (BuLi or MgⁿBu₂). The presence of an electron‐withdrawing ligand such as Cp^Ph3 allows high syndioregularity, up to 81.8% at 0 °C, together with the highest conversion. There is quite good concordance between calculated and experimental molecular data in THF. Divalent Cp^*′₂Sm^II(THF) and (Cp^Ph3)₂Sm^II(THF) are active as single‐component initiators; the former affords PMMA 88% syndiotactic at 0 °C. Copyright © 2005 John Wiley & Sons, Ltd.     

Novel unsymmetrical PCP′ pincer ligands and their palladium(II) complexes

Synthetic routes towards novel PCP′ pincer ligands were devised. Ligand 1-(Pr₂ⁱPOCH₂)-3-(Bu₂^tPCH₂)(C₆H₄) is prepared in a three step synthesis from 1,3-benzenedimethanol and 1-(Pr₂ⁱPO)-3-(Bu₂^tPCH₂)(C₆H₄) is accessible in three steps from 3-hydroxybenzylalcohol. Both their palladium(II) complexes are prepared in good yields but are distinctly different since [PdCl{(C₆H₃)(OPPr₂ⁱ)-2-(CH₂PBu₂^t)-6}] possesses two five-membered palladacycles, whereas [PdCl{(C₆H₃)(CH₂PBu₂^t)-2-(CH₂OPPr₂ⁱ)-6}] is unusual for a pincer complex in that it contains both five- and six-membered palladacycles. Both compounds also represent the first examples of pincer complexes where one donor is a phosphinite and the other is a phosphine. The X-ray structures of these complexes were solved and are discussed. The data reveal that an increase in the metallacycle ring-size leads to changes in bond lengths, but more importantly to significant increases in the bond angles.     

Syntheses and structure of the first eight-membered fluoro and chloro hafnium siloxane complexes

The eight-membered chloro hafnium siloxane complex [Cl₂HfOtBu₂SiO(THF)₂]₂ 2 has been prepared by the reaction of hafnium tetrachloride and tBu₂Si(OSnMe₃)₂ 1 . The X-ray single crystal structure of [Cl₂HfOtBu₂SiO(THF)₂]₂ is reported. The reaction of 2 with Me₃SnF in a molar ratio of 1:4 leads to the corresponding fluoro complex 3 . The reaction of [(C₅Me₅)HfCl₃] with the lithiated silanediol tBu₂Si(OLi)₂ yields [(C₅Me₅)ClHfOtBu₂SiO]₂ 4 .     

The “Metallo”-Diels–Alder Reactions: Examining the Metalloid Behavior of Germanimines

Addition of MesN₃ (Mes=2,4,6-Me₃C₆H₂) to germylene [(NON^tBu)Ge] (NON^tBu=O(SiMe₂NtBu)₂) ( 1 ) gives germanimine, [(NON^tBu)Ge=NMes] ( 2 ). Compound 2 behaves as a metalloid, showing reactivity reminiscent of both transition metal-imido complexes, undergoing [2+2] addition with heterocumulenes and protic sources, as well as an activated diene, undergoing a [4+2] cycloaddition, or “metallo”-Diels–Alder, reaction. In the latter case, the diene includes the Ge=N bond and π-system of the Mes substituent, which is reactive towards dienophiles including benzaldehyde, benzophenone, styrene, and phenylacetylene.     

Factors affecting product distributions in ethylene/styrene copolymerization by (aryloxo)(cyclopentadienyl)titanium complexes‐MAO catalyst systems

Ethylene/styrene copolymerizations using Cp′TiCl₂(O‐2,6‐ⁱPr₂C₆H₃) [Cp′ = Cp* (C₅Me₅, 1 ), 1,2,4‐Me₃C₅H₂ ( 2 ), tert‐BuC₅H₄ ( 3 )]‐MAO catalyst systems were explored under various conditions. Complexes 2 and 3 exhibited both high catalytic activities (activity: 504–6810 kg‐polymer/mol‐Ti h) and efficient styrene incorporations at 25, 40°C (ethylene 6 atm), affording relatively high molecular weight poly (ethylene‐co‐styrene)s with unimodal molecular weight distributions as well as with uniform styrene distributions (M_w = 6.12–13.6 × 10⁴, M_w/M_n = 1.50–1.71, styrene 31.7–51.9 mol %). By‐productions of syndiotactic polystyrene (SPS) were observed, when the copolymerizations by 1 – 3 ‐MAO catalyst systems were performed at 55, 70 °C (ethylene 6 atm, SPS 9.0–68.9 wt %); the ratios of the copolymer/SPS were affected by the polymerization temperature, the [styrene]/[ethylene] feed molar ratios in the reaction mixture, and by both the cyclopentadienyl fragment (Cp′) and anionic ancillary donor ligand (L) in Cp′TiCl₂(L) (L = Cl, O‐2,6‐ⁱPr₂C₆H₃ or N=C^tBu₂) employed. Co‐presence of the catalytically‐active species for both the copolymerization and the homopolymerization was thus suggested even in the presence of ethylene; the ratios were influenced by various factors (catalyst precursors, temperature, styrene/ethylene feed molar ratio, etc.). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4162–4174, 2008     

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.     

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.     

Reaktionen von tBu2P–P=P(Me)tBu2 mit (Et3P)2NiCl2 und [{η2‐C2H4}Ni(PEt3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXIII. Reactions of ^tBu₂P–P=P(Me)^tBu₂ with (Et₃P)₂NiCl₂ and [{η²‐C₂H₄}Ni(PEt₃)₂] ^tBu₂P–P=P(Me)^tBu₂ ( 1 ) forms with (Et₃P)₂NiCl₂ ( 2 ) and Na(Nph) the [μ‐(1,3 : 2,3‐η‐^tBu₂P₄^tBu₂){Ni(PEt₃)Cl}₂] ( 3 ) as main product. Using Na/Hg instead as reducing agent the Ni⁰ compounds [{η²‐^tBu₂P–P}Ni(PEt₃)₂] ( 4 ), [{η²‐^tBu₂P–P=P–P^tBu₂}Ni(PEt₃)₂] ( 5 ) and [(Et₃P)Ni(μ‐P^tBu₂)]₂ ( 6 ) with four‐membered Ni₂P₂ ring result. [{η²‐C₂H₄}Ni(PEt₃)₂] yields with 1 also 4 . The compounds were characterized by ¹H and ³¹P{¹H} NMR investigations and 3 also by a single crystal X‐ray analysis. It crystallizes triclinic in the space group P 1 with a = 1129.4(2), b = 1256.8(3), c = 1569.5(3) pm, α = 72.44(3)°, β = 70.52(3)° and γ = 74.20(3)°.