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.     

Phase-transfer Tsuji—Trost allylation of CH-acids with the assistance of palladium complexes with bidentate P<Superscript>III</Superscript>—N—P<Superscript>III</Superscript> ligands

The Tsuji—Trost allylation of CH acids, in particular, those of the YCH₂CO₂Et type (Y = CO₂Et, C(O)Me, CN), with allylic acetates in the K₂CO₃—DMF system in the presence of palladium catalysts with ligands RN(PPh₂)₂ (R = Ph, Prⁱ, c-C₆H₁₁) is accomplished.     

Platinum Indolylphosphine Fluorido and Polyfluorido Complexes: An Interplay between Cyclometallation,Fluoride Migration,and Hydrogen Bonding

The reaction of [PtCl₂(COD)] (COD=1,5-cyclooctadiene) with diisopropyl-2-(3-methyl)indolylphosphine (iPr₂P(C₉H₈N)) led to the formation of the platinum(ii ) chlorido complexes, cis-[PtCl₂{iPr₂P(C₉H₈N)}₂] ( 1 ) and trans-[PtCl₂{iPr₂P(C₉H₈N)}₂] ( 2 ). The cis-complex 1 reacted with NEt₃ yielding the complex cis-[PtCl{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}] ( 3 ) bearing a cyclometalated κ²-(P,N)-phosphine ligand, while the isomer 2 with a trans-configuration did not show any reactivity towards NEt₃. Treatment of 1 or 3 with (CH₃)₄NF (TMAF) resulted in the formation of the twofold cyclometalated complex cis-[Pt{κ²-(P,N)-iPr₂P(C₉H₇N)}₂] ( 4 ). The molecular structures of the complexes 1–4 were determined by single-crystal X-ray diffraction. The fluorido complex cis-[PtF{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}] ⋅ (HF)₄ ( 5 ⋅ (HF)₄) was formed when complex 4 was treated with different hydrogen fluoride sources. The Pt(ii ) fluorido complex 5 ⋅ (HF)₄ exhibits intramolecular hydrogen bonding in its outer coordination sphere between the fluorido ligand and the NH group of the 3-methylindolyl moiety. In contrast to its chlorido analogue 3 , complex 5 ⋅ (HF)₄ reacted with CO or the ynamide 1-(2-phenylethynyl)-2-pyrrolidinone to yield the complexes trans-[Pt(CO){κ²-(P,C)-iPr₂P(C₉H₇NCO)}{iPr₂P(C₉H₈N)}][F(HF)₄] ( 7 ) and a complex, which we suggest to be cis-[Pt{C=C(Ph)OCN(C₃H₆)}{κ²-(P,N)-iPr₂P(C₉H₇N)}{iPr₂P(C₉H₈N)}][F(HF)₄] ( 9 ), respectively. The structure of 9 was assigned on the basis of DFT calculations as well as NMR and IR data. Hydrogen bonding of HF and NH to fluoride was proven to be crucial for the existence of 7 and 9 .     

Elusive Terminal Copper Arylnitrene Intermediates

We report herein three new modes of reactivity between arylazides N₃Ar with a bulky copper(I) β-diketiminate. Addition of N₃Ar^X3 (Ar^X3=2,4,6-X₃C₆H₂; X=Cl or Me) to [ⁱPr₂NN]Cu(NCMe) results in triazenido complexes from azide attack on the β-diketiminato backbone. Reaction of [ⁱPr₂NN]Cu(NCMe) with bulkier azides N₃Ar leads to terminal nitrenes [ⁱPr₂NN]Cu]=NAr that dimerize via formation of a C−C bond at the arylnitrene p-position to give the dicopper(II) diketimide 4 (Ar=2,6-ⁱPr₂C₆H₃) or undergo nitrile insertion to give diazametallocyclobutene 8 (Ar=4-Ph-2,6-iPr₂C₆H₂). Importantly, reactivity studies reveal both 4 and 8 to be “masked” forms of the terminal nitrenes [ⁱPr₂NN]Cu=NAr that undergo nitrene group transfer to PMe₃, ^tBuNC, and even into a benzylic sp³ C−H bond of ethylbenzene.     

Addition Reactions of Me3SiCN with Aldehydes Catalyzed by Aluminum Complexes Containing in their Coordination Sphere O,S, and N Ligands

The reaction of one equivalent of LAlH₂ ( 1 ; L=HC(CMeNAr)₂, Ar=2,6‐iPr₂C₆H₃, β‐diketiminate ligand) with two equivalents of 2‐mercapto‐4,6‐dimethylpyrimidine hydrate resulted in LAl[(μ‐S)(m‐C₄N₂H)(CH₂)₂]₂ ( 2 ) in good yield. Similarly, when N‐2‐pyridylsalicylideneamine, N‐(2,6‐diisopropylphenyl)salicylaldimine, and ethyl 3‐amino‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐2‐carboxylate were used as starting materials, the corresponding products LAl[(μ‐O)(o‐C₆H₄)CN(C₅NH₄)]₂ ( 3 ), LAlH[(μ‐O)(o‐C₄H₄)CN(2,6‐iPr₂C₆H₃)] ( 4 ), and LAl[(μ‐NH)(o‐C₈SH₈)(COOC₂H₅)]₂ ( 5 ) were isolated. Compounds 2 – 5 were characterized by ¹H and ¹³C NMR spectroscopy as well as by single‐crystal X‐ray structural analysis. Surprisingly, compounds 2 – 5 exhibit good catalytic activity in addition reactions of aldehydes with trimethylsilyl cyanide (TMSCN).     

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.     

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.     

An H-Substituted Rhodium Silylene

Divergent reactivity of organometallic rhodium(I) complexes, which led to the isolation of neutral rhodium silylenes, is described. Addition of PhRSiH₂ (R=H, Ph) to the rhodium cyclooctene complex (^iPrNNN)Rh(COE) (1-COE; ^iPrNNN=2,5-[iPr₂P=N(4-iPrC₆H₄)]₂N(C₆H₂)⁻, COE=cyclooctene) resulted in the oxidative addition of an Si−H bond, providing rhodium(III) silyl hydride complexes (^iPrNNN)Rh(H)SiHRPh (R=H, 2 -SiH₂Ph; Ph, 2 -SiHPh₂). When the carbonyl complex (^iPrNNN)Rh(CO) ( 1 -CO) was treated with hydrosilanes, base-stabilized rhodium(I) silylenes κ²-N,N-(^iPrNNN)(CO)Rh=SiRPh (R=H, 3 -SiHPh; Ph, 3 -SiPh₂) were isolated and characterized using multinuclear NMR spectroscopy and X-ray crystallography. Both silylene species feature short Rh−Si bonds [2.262(1) Å, 3 -SiHPh; 2.2702(7) Å, 3 -SiPh₂] that agree well with the DFT-computed structures. The overall reaction led to a change in the ^iPrNNN ligand bonding mode (κ³→κ²) and loss of H₂ from PhSiRH₂, as corroborated by deuterium labelling experiments.     

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.     

A Capped Octahedral MHC6 Compound of a Platinum Group Metal

A MHC₆ complex of a platinum group metal with a capped octahedral arrangement of donor atoms around the metal center has been characterized. This osmium compound OsH{κ²‐C,C‐(PhBIm‐C₆H₄)}₃, which reacts with HBF₄ to afford the 14 e^? species [Os{κ²‐C,C‐(PhBIm‐C₆H₄)}(Ph₂BIm)₂]BF₄ stabilized by two agostic interactions, has been obtained by reaction of OsH₆(PiPr₃)₂ with N,N′‐diphenylbenzimidazolium chloride ([Ph₂BImH]Cl) in the presence of NEt₃. Its formation takes place through the C,C,C‐pincer compound OsH₂{κ³‐C,C,C‐(C₆H₄‐BIm‐C₆H₄)}(PiPr₃)₂, the dihydrogen derivative OsCl{κ²‐C,C‐(PhBIm‐C₆H₄)}(η²‐H₂)(PiPr₃)₂, and the five‐coordinate osmium(II) species OsCl{κ²‐C,C‐(PhBIm‐C₆H₄)}(PiPr₃)₂.     

Syntheses and Structures of Zinc Bis(phosphinimino)methanide Complexes

Reactions of bis(phosphinimino)methanes H₂C(PPh₂NR)₂ [R = SiMe₃ (L¹H), Ph (L²H), 2,6‐iPr₂‐C₆H₃ (DIPP) (L³H)] with ZnR₂ (R = Me, Et) yielded the corresponding bis(phosphinimino)methanide zinc complexes LZnMe [L² ( 1 ), L³ ( 2 )] and LZnEt [L¹ ( 3 ), L² ( 4 ), and L³ ( 5 )]. Complexes 1 – 5 were characterized by heteronuclear NMR (¹H, ¹³C, ³¹P) and IR spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction.     

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.     

Synthese und eigenschaften neur kupfer- und gold-komplexe des typs C5H5MPR3, C5Me5MPR3 und R″C2MPR3 (M = Cu,Au) sowie die kristallstruktur von C5H5AuPPr3i

The complexes C₅H₅CuPR₃ (R = Me, Prⁱ), C₅H₅AuPR₃ (R = Me, Prⁱ), C₅Me₅CuPR₃ (R = Me, Prⁱ, Ph) and C₅Me₅AuPR₃ (R = Prⁱ, Ph) are prepared from [ClCuPR₃]_n or ClAuPR₃ and LiC₅H₅ (TlC₅H₅) or LiC₅Me₅, respectively. According to the ¹H and ¹³C NMR spectra, the cyclopentadienyl and pentamethylcyclopentadienylgold compounds are fluxional in solution. The X-ray crystal structure of C₅H₅AuPPr₃ⁱ has been determined at ?120°C. The gold atom is in a linear arrangement (PAuC(1) = 177.0(2)°) and primarily σ-bonded to the cyclopentadienyl ring which shows a weak “slip distortion” toward a η³-mode of coordination. The complexes C₅R′₅AuPR₃ (R′ = H, Me) and C₅Me₅CuPPr₃ⁱ react with 1-alkynes such as C₂H₂, HC₂Ph and HC₂CO₂Me to form alkinylgold and copper compounds R″C₂MPR₃. They have been characterized by IR, UV and NMR (¹H, ¹³C, ³¹P) spectroscopy.     

CycloSiFA: The Next Generation of Silicon-Based Fluoride Acceptors for Positron Emission Tomography (PET)

The ring-opening Si-fluorination of a variety of azasilole derivatives cyclo-1-(iPr₂Si)−4-X−C₆H₃−2-CH₂NR ( 4 : R=2,6-iPr₂C₆H₃, X=H; 4 a : R=2,4,6-Me₃C₆H₂, X=H; 9 : R=2,6-iPr₂C₆H₃, X=tBuMe₂SiO; 10 : R=2,6-iPr₂C₆H₃, X=OH; 13 : R=2,6-iPr₂C₆H₃, X=HCCCH₂O; 22 : R=2,6-iPr₂C₆H₃, X=tBuMe₂SiCH₂O) with different ¹⁹F-fluoride sources was studied, optimized and the experience gained was used in a translational approach to create a straightforward ¹⁸F-labelling protocol for the azasilole derivatives [¹⁸F] 6 and [¹⁸F] 14 . The latter constitutes a potential clickable CycloSiFA prosthetic group which might be used in PET tracer development using Cu-catalysed triazole formation. Based on our findings, CycloSiFA has the potential to become a new entry into non-canonical labelling methodologies for radioactive PET tracer development.     

Stabilization of a Silaaldehyde by its η2 Coordination to Tungsten

Treatment of pyridine‐stabilized silylene complexes [(η⁵‐C₅Me₄R)(CO)₂(H)W?SiH(py)(Tsi)] (R=Me, Et; py=pyridine; Tsi=C(SiMe₃)₃) with an N‐heterocyclic carbene ^MeIⁱPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) caused deprotonation to afford anionic silylene complexes [(η⁵‐C₅Me₄R)(CO)₂W?SiH(Tsi)][H^MeIⁱPr] (R=Me ( 1‐Me ); R=Et ( 1‐Et )). Subsequent oxidation of 1‐Me and 1‐Et with pyridine‐N‐oxide (1 equiv) gave anionic η²‐silaaldehydetungsten complexes [(η⁵‐C₅Me₄R)(CO)₂W{η²‐O?SiH(Tsi)}][H^MeIⁱPr] (R=Me ( 2‐Me ); R=Et ( 2‐Et )). The formation of an unprecedented W‐Si‐O three‐membered ring was confirmed by X‐ray crystal structure analysis.     

N,N-Dialkylcarbamato Complexes of the d10 cations of copper,silver, and gold

The reaction of CuO'Bu with CO₂, and ⁱPr₂NH in the presence of PPh₃, gives the dialkylcarbamato complex [Cu(O₂CNⁱPr₂)(PPh₃)₂] ( 1 ). The CO₂/R₂NH system (R = Me, Et) in an appropriate organic medium reacts with Ag₂O giving the corresponding N,N-dialkylcarbamato complexes of analytical formula [Ag(C₂CNR₂)] (R = Me, 2 ; R = Et, 3 ). The methyl derivative 2 was characterized by X-ray diffraction methods. Crystal data of 2 : for [Ag₂(O₂CNMe₂)₂], C₆H₁₂Ag₂N₂O₄, mol. wt. 391.9; monoclinic, space group P2₁/c, a = 12.08(1), b = 3.797(2), c = 11.316(7) Å, β = 113.37(6)°, V = 476.3 ų, Z = 2, D_c = 2.732 g cm^?3; μ(MoK_α) = 40.64 cm^?1, F(000) = 376.0; R = 0.059, R_w = 0.067; g.o.f. 1.27. The structure consists of dinuclear [(Ag₂OCNMe₂)₂] units with slightly distorted linearly two-coordinated Ag-atoms containing bridging carbamato groups to form a substantially planar eight-membered ring with an intra-annular Ag? Ag distance of 2.837(2) Å; the dinuclear units are further joined by Ag? O bonds to form an infinite array. Compound 3 , which is presumably dinuclear, as suggested by cryoscopic measurements in benzene, undergoes a structural fission with PPh₃, giving the mononuclear triphenylphosphine derivative [Ag(O₂CNEt₂)(PPh₃)₂] ( 4 ). The amine-catalyzed conversion of Ag₂O into Ag₂CO₃, in the presence of the ⁱPr₂NH/CO₂ system, is also reported. Cl-Exchange from [AuCl(PPh₃)] with [Ag(O₂CNEt₂)] ( 3 ) gives the first N,N-dialkylcarbamato complex of gold, namely [Au(O₂CNEt₂)(PPh₃)] ( 5 ), which crystallizes in the monoclinic system: C₂₃H₂₅AuNO₂P · 0.5 C₇H₁₆, mol. wt. 625.5, space group P2₁/c; a = 13.212(5), b = 12.25(1), c = 16.795(6) Å, β = 109.09(2)°, V = 2568(2) Å₃, Z = 4, D_c, = 1.618 g cm^?3; μ(AgK_α) = 31.40 cm^?1, F(000) = 1236.0; R = 0.058; R_w = 0.064; g.o.f. 2.121. The compound contains two-coordinated Au-atom, namely to the P-atom and to the O-atom of the monodentate carbamato group, the P? Au? O bond angle being 174.7(3)°. The reaction with MeI showed these compounds to react predominantly at the carbamato O-atom giving the corresponding urethanes R₂NCO₂Me. Evidence was gathered for the transient coordination of CO to Ag in 3 .     

Activation of CH bonds by ruthenium hydride complexes. Deuteration of triisopropyl and tricyclohexylphosphine using C6D6 or C7D8 as the deuterium source

Complexes of the type RuH₄P₃ (P=P(Prⁱ)₃, P(C₆H₁₁)₃ or P(N(C₂H₅)₂)₃) in solution in deuterated aromatic solvents undergo H-D exchange between the solvent and the coordinated phosphines. The reaction works better with RuH₄P(Prⁱ₃)₃, in which about 70% of the phosphine protons can be so exchanged. A mechanism involving dissociation of a phosphine followed by activation of the solvent CD bond and the phosphine CH bond is proposed.     

Synthese von verbrückend substituierten sekundären Phosphanen sowie deren Reaktionen mit Triisopropylindium

In this work we report the synthesis and characterisation of the 1.5‐diphosphanyldiethylether O{C₂H₄PH(SiiPr₃)}₂ ( 2 ) in which two silyl‐substituted phosphine groups are linked by an ether bridge as well as the compound O(SiiPr₂PHEt)₂ ( 3 ) where two ethyl substitute phosphine groups are connected by a siloxane bridge. In addition, we describe the metalation of 2 and 3 with triisopropylindium. These reactions lead to the compounds [O{C₂H₄P(SiiPr₃)IniPr₂}₂] ( 4 ) and [O{SiiPr₂P(Et)IniPr₂}₂] ( 5 ) with In₂P₂ ring structures.     

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.     

Synthesis of a C(sp2)-bridged Phosphine-Borane by Ionic Coupling

The vinyl carbenoid H₂C=CBr(Li) has been used as key precursor to prepare a geminal C(sp²)-bridged phosphine-borane. Starting from bromoethene, two sequences of lithiation/electrophilic trapping, with ClPiPr₂ and FBMes₂ respectively, affords iPr₂P–C(=CH₂)–BMes₂ 3 [Mes = 2,4,6-(H₃C)₃C₆H₂]. This new phosphine-borane 3 was characterized by multi-nuclear NMR and mass spectroscopy. It adopts a monomeric open structure without P→B interaction. A few crystals of a secondary product 4 were analyzed by X-ray diffraction, revealing an unusual dimeric structure.