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1.
The reactions of vanadocene and its halides Cp2VCl and Cp2VCl2 with R3MNCX (M  Sn, Si, X  O, S) and R2M(NCX)2 in various molar ratios have been studied. The reactions proceed either by an exchange of groups, with no change in the oxidation state of vanadium, or by an oxidative addition of pseudohalide ligand: VII → VIII; VIII → VIV. Oxidative addition results in the formation of (R3M)2 or gaseous hydrogen (in the reaction with HCl) in the reaction products.We have prepared the first ever monomeric and readily oxidisable d2-complexes of VIII of Cp2VNCX-type and asymmetric d1-complexes of Cp2V(Cl)NCX type, which, although rather stable in air, undergo disproportionation into symmetric d1-complexes on heating. In transmetallation reactions the ligand activity is found to increase in the order C1 < NCO < NCS. The complexes were characterised by GLC analysis, IR and ESR spectroscopy. A general scheme for the disproportionation reaction of asymmetric complexes of vanadocene is supported by differential thermal analysis data.  相似文献   

2.
Reaction of Trimethylsilylethers of Unsaturated Alcohols with Schwartz Reagent – Stabilisation of Cyclic Zirconiumorganic Compounds by the Moiety Cp2ZrH2 Besides the normal product of hydrozirconation the reaction of allyltrimethylsilylethers CH2? CHC(R1R2)OSi(CH3)3 ( I : R1 = R2 = H, VIII : R1 = R2 = CH3, X : R1 = H, R2 = CH3) with Cp2Zr(H)Cl yields, as a result of a hydrogenation of the Si? O bond, trimethylsilane and a series of compounds with a Zr? O bond. Depending on the substitution of the α-C atom either dimeric chelates ( III ) or binuclear complexes of the type Cp2Zr(Cl)CH2CH2C(R1R2)OZr(Cl)Cp2 ( IX : R1 = R2 = CH3; XII : R1 = H, R2 = CH3) are formed. Starting with X and excess Cp2Zr(H)Cl the binuclear compound XIII is obtained which may be considered as an adduct of Cp2ZrH2 to the unsaturated chelate Compound XVII with a structure analogous to XIII is synthesized by the reaction of IX with Cp2ZrH2. The 1H-NMR spectrum is in accordance with the existence of cis-trans-isomers of this complex.  相似文献   

3.
The use of [Cp′′2Zr(η1:1-E4)] (E=P ( 1 a ), As ( 1 b ), Cp′′=1,3-di-tert-butyl-cyclopentadienyl) as phosphorus or arsenic source, respectively, gives access to novel stable polypnictogen transition metal complexes at ambient temperatures. The reaction of 1 a/1 b with [CpRNiBr]2 (CpR=CpBn (1,2,3,4,5-pentabenzyl-cyclopentadienyl), Cp′′′ (1,2,4-tri-tert-butyl-cyclopentadienyl)) was studied, to yield novel complexes depending on steric effects and stoichiometric ratios. Besides the transfer of the complete En unit, a degradation as well as aggregation can be observed. Thus, the prismane derivatives [(Cp′′′Ni)2(μ,η3:3-E4)] ( 2 a (E=P); 2 b (E=As)) or the arsenic containing cubane [(Cp′′′Ni)33-As)(As4)] ( 5 ) are formed. Furthermore, the bromine bridged cubanes of the type [(CpRNi)3{Ni(μ-Br)}(μ3-E)4]2 (CpR=Cp′′′: 6 a (E=P), 6 b (E=As), CpR=CpBn: 8 a (E=P), 8 b (E=As)) can be isolated. Here, a stepwise transfer of En units is possible, with a cyclo-E42− ligand being introduced and unprecedented triple-decker compounds of the type [{(CpRNi)3Ni(μ3-E)4}2(μ,η4:4-E′4)] (CpR=CpBn, Cp′′′; E/E′=P, As) are obtained.  相似文献   

4.
N–O Bond Cleavage in O-silylated Oximes by Reaction with a Titanocene-Alkyne Complex Cp2Ti(Me3SiC2SiMe3) 1 reacts with alicyclic and aliphatic O-silylated ketoximes of type R1R2C=NOSiMe3 ( 2 : R1R2 = (CH2)5; 3 : R1 = R2 = Me) under N–O bond breaking to the titanocene complexes Cp2Ti(OSiMe3)(N=CR1R2) 6 (R1R2 = (CH2)5) and 7 (R1 = R2 = Me). The structure of 6 was obtained by X-ray crystal structure analysis ( 6 : triclinic, space group P1, Z = 2, a = 9.486(1), b = 9.865(1), c = 12.305(2) Å, α = 107.19(1), β = 96.08(1), γ = 111.08(1)°).  相似文献   

5.
Two transition-metal atoms bridged by hydrides may represent a useful structural motif for N2 activation by molecular complexes and the enzyme active site. In this study, dinuclear MoIV-FeII complexes with bridging hydrides, CpRMo(PMe3)(H)(μ-H)3FeCp* ( 2 a ; CpR=Cp*=C5Me5, 2 b ; CpR=C5Me4H), were synthesized via deprotonation of CpRMo(PMe3)H5 ( 1 a ; CpR=Cp*, 1 b ; CpR=C5Me4H) by Cp*FeN(SiMe3)2, and they were characterized by spectroscopy and crystallography. These Mo−Fe complexes reveal the shortest Mo−Fe distances ever reported (2.4005(3) Å for 2 a and 2.3952(3) Å for 2 b ), and the Mo−Fe interactions were analyzed by computational studies. Removal of the terminal Mo−H hydride in 2 a – 2 b by [Ph3C]+ in THF led to the formation of cationic THF adducts [CpRMo(PMe3)(THF)(μ-H)3FeCp*]+ ( 3 a ; CpR=Cp*, 3 b ; CpR=C5Me4H). Further reaction of 3 a with LiPPh2 gave rise to a phosphido-bridged complex Cp*Mo(PMe3)(μ-H)(μ-PPh2)FeCp* ( 4 ). A series of Mo−Fe complexes were subjected to catalytic silylation of N2 in the presence of Na and Me3SiCl, furnishing up to 129±20 equiv of N(SiMe3)3 per molecule of 2 b . Mechanism of the catalytic cycle was analyzed by DFT calculations.  相似文献   

6.
Synthesis and Characterization of Metallocene Chelates of Heterocyclic 1,2-Diselenolates Synthesis and properties of metallocen diselenolates Cp2RML (CpR = η5-C5H4CH3 (Cp′); η5-C5(CH3)4 C2H5 (Cpo)) of titanium(IV) and vanadium(IV) with L = dsit (1,3-dithiole-2-thione-4,5-diselenolate), dsise (1,3-dithiole-2-selone-4,5-diselenolate) dsitse (1,3-thiaselenole-2-selone-4,5-diselenolate) and dsis (1,3-diselenole-2-selone-4,5-diselenolate) are described. The structures of these compounds in solution are discussed using 1H, 13C, 77Se NMR and EPR data. Their voltammetric behaviour is investigated in dichloromethane. The activation parameters of the chelate ring inversion of the titanocene diselenolates (Cp2RTiL) and the x-ray structures of Cp2′Ti(dsit), Cp2oTi(dsit); Cp2oTi(dsise) (2 modifications) and Cp2oTi(dsis) are reported.  相似文献   

7.
Hydrogenolysis of alkyl‐substituted cyclopentadienyl (CpR) ligated thorium tribenzyl complexes [(CpR)Th(p‐CH2‐C6H4‐Me)3] ( 1 – 6 ) afforded the first examples of molecular thorium trihydrido complexes [(CpR)Th(μ‐H)3]n (CpR=C5H2(tBu)3 or C5H2(SiMe3)3, n=5; C5Me4SiMe3, n=6; C5Me5, n=7; C5Me4H, n=8; 7 – 10 and 12 ) and [(Cp#)12Th13H40] (Cp#=C5H4SiMe3; 13 ). The nuclearity of the metal hydride clusters depends on the steric profile of the cyclopentadienyl ligands. The hydrogenolysis intermediate, tetra‐nuclear octahydrido thorium dibenzylidene complex [(Cpttt)Th(μ‐H)2]4(μ‐p‐CH‐C6H4‐Me)2 (Cpttt=C5H2(tBu)3) ( 11 ) was also isolated. All of the complexes were characterized by NMR spectroscopy and single‐crystal X‐ray analysis. Hydride positions in [(CpMe4)Th(μ‐H)3]8 (CpMe4=C5Me4H) were further precisely confirmed by single‐crystal neutron diffraction. DFT calculations strengthen the experimental assignment of the hydride positions in the complexes 7 to 12 .  相似文献   

8.
Secondary Hydroxyalkylphosphanes: Synthesis and Characterization of Mono‐, Bis‐ and Trisalkoxyphosphane‐substituted Zirconium Complexes and the Heterobimetallic Trinuclear Complex [Cp2Zr{O(CH2)3PHMes(AuCl)}2] The secondary hydroxyalkylphosphanes RPHCH2OH [R = 2,4,6‐Me3C6H2 (Mes) ( 1 ), 2,4,6‐iPr3C6H2 (Tipp) ( 2 )], 1‐AdPH‐2‐OH‐cyclo‐C6H10 ( 3 ) and RPH(CH2)3OH [R = Ph ( 4 ), Mes ( 5 ), Tipp ( 6 ), Cy ( 7 ), tBu ( 8 )] were obtained from primary phosphanes RPH2 and formaldehyde ( 1 , 2 ) or from LiPHR and cyclohexene oxide ( 3 ) or trimethylene oxide ( 4 ‐ 8 ). Starting from 5 or 7 and [CpR2ZrMe2] [CpR = C5EtMe4 (Cp°), C5H5 (Cp), C5MeH4 (Cp′)], the monoalkoxyphosphane‐substituted zirconocene complexes [CpR2Zr(Me){O(CH2)3PHMes}] [CpR = Cp° ( 9 ), Cp ( 10 )] were prepared. With [CpR2ZrCl2], the bisalkoxyphosphane‐substituted complexes [Cp′2Zr{O(CH2)3PHMes}2] ( 11 ) and [Cp2Zr{O(CH2)3PHCy}2] ( 12 ) are obtained, and with [TpRZrCl3], the trisalkoxyphosphane‐substituted zirconium complexes [TpRZr{O(CH2)3PHMes}3] [TpR = trispyrazolylborato (Tp) ( 13 ), TpR = tris(3,5‐dimethyl)pyrazolylborato (Tp*) ( 14 )] are prepared. The reaction of 5 with [AuCl(tht)] (tht = tetrahydrothiophene) yielded the mononuclear complex [AuCl{PHMes(CH2)3OH}] ( 15 ). The trinuclear complex [Cp2Zr{O(CH2)3PHMes(AuCl)}2] ( 16 ) was obtained from [Cp2ZrCl2] and 15 . Compounds 1 ‐ 16 were characterized spectroscopically (1H‐, 31P‐, 13C‐NMR; IR; MS) and compound 2 also by crystal structure determination. The bis‐ and trisalkoxyphosphane‐substituted complexes 11‐14 and 16 were obtained as mixtures of two diastereomers which could not be separated.  相似文献   

9.
The chemistry of polyphosphorus cations has rapidly developed in recent years, but their coordination behavior has remained mostly unexplored. Herein, we describe the reactivity of [P5R2]+ cations with cyclopentadienyl metal complexes. The reaction of [CpArFe(μ‐Br)]2 (CpAr=C5(C6H4‐4‐Et)5) with [P5R2][GaCl4] (R=iPr and 2,4,6‐Me3C6H2 (Mes)) afforded bicyclo[1.1.0]pentaphosphanes ( 1‐R , R=iPr and Mes), showing an unsymmetric “butterfly” structure. The same products 1‐R were formed from K[CpAr] and [P5R2][GaCl4]. The cationic complexes [CpArCo(η4‐P5R2)][GaCl4] ( 2‐R [GaCl4], R=iPr and Cy) and [(CpArNi)23:3‐P5R2)][GaCl4] ( 3‐R [GaCl4]) were obtained from [P5R2][GaCl4] and [CpArM(μ‐Br)]2 (M=Co and Ni) as well as by using low‐valent “CpArMI” sources. Anion metathesis of 2‐R [GaCl4] and 3‐R [GaCl4] was achieved with Na[BArF24]. The P5 framework of the resulting salts 2‐R [BArF24] can be further functionalized with nucleophiles. Thus reactions with [Et4N]X (X=CN and Cl) give unprecedented cyano‐ and chloro‐functionalized complexes, while organo‐functionalization was achieved with CyMgCl.  相似文献   

10.
The influence of differently substituted cyclopentadienyl CpR ligands on the reaction outcome of [CpRFe(CO)2]2 (CpR = C5Me5, EtC5Me4, 1,3-Bu2tC5H3) with As4 is examined. For C5Me5 and EtC5Me4, the pentaarsaferrocene derivatives [CpRFe(η5-As5)] are formed together with [(CpRFe)3As6] and [(CpRFe)3As6{(η3-As3)Fe}], while for 1,3-Bu2tC5H3 only [(CpRFe)3As6] is formed. The reaction of [(Me5C5Fe)3As6{(η3-As3)Fe}] with Tl+ leads to [{(Me5C5Fe)3As6Fe}2(μ,η33-As3)]2+ representing an unexpected dicationic cluster.  相似文献   

11.
In the in situ Grignard metalation method (iGMM), the addition of bromoethane to a suspension of magnesium turnings and cyclopentadienes [C5H6 (HCp), C5H5-Si(iPr)3 (HCpTIPS)] in diethyl ether smoothly yields heteroleptic [(Et2O)Mg(CpR)(μ-Br)]2 (CpR=Cp ( 1 ), CpTIPS ( 2 )). The Schlenk equilibrium of 2 in toluene leads to ligand exchange and formation of homoleptic [Mg(CpR)2] ( 3 ) and [(Et2O)MgBr(μ-Br)]2 ( 4 ). Interfering solvation and aggregation as well as ligand redistribution equilibria hamper a quantitative elucidation of thermodynamic data for the Schlenk equilibrium of 2 in toluene. In ethereal solvents, mononuclear species [(Et2O)2Mg(CpTIPS)Br] ( 2’ ), [(Et2O)nMg(CpTIPS)2] ( 3’ ), and [(Et2O)2MgBr2] ( 4’ ) coexist. Larger coordination numbers can be realized with cyclic ethers like tetrahydropyran allowing crystallization of [(thp)4MgBr2] ( 5 ). The interpretation of the temperature-dependency of the Schlenk equilibrium constant in diethyl ether gives a reaction enthalpy ΔH and reaction entropy ΔS of −11.5 kJ mol−1 and 60 J mol−1, respectively.  相似文献   

12.
Tetramethylaluminato/halogenido(X) ligand exchange reactions in half-sandwich complexes [CpRLa(AlMe4)2] are feasible in non-coordinating solvents and provide access to large coordination clusters of the type [CpRLaX2]x. Incomplete exchange reactions generate the hexalanthanum clusters [CpR6La6X8(AlMe4)4] (CpR=Cp*=C5Me5, X=I; CpR=Cp′=C5H4SiMe3, X=Br, I). Treatment of [Cp*La(AlMe4)2] with two equivalents Me3SiI gave the nonalanthanum cluster [Cp*LaI2]9, while the exhaustive reaction of [Cp′La(AlMe4)2] with the halogenido transfer reagents Me3GeX and Me3SiX (X=I, Br, Cl) produced a series of monocyclopentadienyl rare-earth-metal clusters with distinct nuclearity. Depending on the halogenido ion size the homometallic clusters [Cp′LaCl2]10 and [Cp′LaX2]12 (X=Br, I) could be isolated, whereas different crystallization techniques led to the aggregation of clusters of distinct structural motifs, including the desilylated cyclopentadienyl-bridged cluster [(μ-Cp)2Cp′8La8I14] and the heteroaluminato derivative [Cp′10La10Br18(AlBr2Me2)2]. The use of the Cp′ ancillary ligand facilitates cluster characterization by means of NMR spectroscopy.  相似文献   

13.
By applying the proper stoichiometry of 1:2 to [CpRFe(η5‐P5)] and CuX (X=Cl, Br) and dilution conditions in mixtures of CH3CN and solvents like CH2Cl2, 1,2‐Cl2C6H4, toluene, and THF, nine spherical giant molecules having the simplified general formula [CpRFe(η5‐P5)]@[{CpRFe(η5‐P5)}12{CuX}25(CH3CN)10] (CpR5‐C5Me5 (Cp*); η5‐C5Me4Et (CpEt); X=Cl, Br) have been synthesized and structurally characterized. The products consist of 90‐vertex frameworks consisting of non‐carbon atoms and forming fullerene‐like structural motifs. Besides the mostly neutral products, some charged derivatives have been isolated. These spherical giant molecules show an outer diameter of 2.24 (X=Cl) to 2.26 nm (X=Br) and have inner cavities of 1.28 (X=Cl) and 1.20 nm (X=Br) in size. In most instances the inner voids of these nanoballs encapsulate one molecule of [Cp*Fe(η5‐P5)], which reveals preferred orientations of π–π stacking between the cyclo‐P5 rings of the guest and those of the host molecules. Moreover, π–π and σ–π interactions are also found in the packing motifs of the balls in the crystal lattice. Electrochemical investigations of these soluble molecules reveal one irreversible multi‐electron oxidation at Ep=0.615 V and two reduction steps (?1.10 and ?2.0 V), the first of which corresponds to about 12 electrons. Density functional calculations reveal that during oxidation and reduction the electrons are withdrawn or added to the surface of the spherical nanomolecules, and no Cu2+ species are involved.  相似文献   

14.
The oxidation of the 28 VE cyclo‐E6 triple‐decker complexes [(CpRMo)2(μ,η66‐E6)] (E=P, CpR=Cp( 2 a ), Cp*( 2 b ), CpBn( 2 c )=C5(CH2Ph)5; E=As, CpR=Cp*( 3 )) by Cu+ or Ag+ leads to cationic 27 VE complexes that retain their general triple‐decker geometry in the solid state. The obtained products have been characterized by cyclic voltammetry (CV), EPR, Evans NMR, multinuclear NMR spectroscopy, MS, and structural analysis by single‐crystal X‐ray diffraction. The cyclo‐E6 middle decks of the oxidized complexes are distorted to a quinoid ( 2 a ) or bisallylic ( 2 b , 2 c , 3 ) geometry. DFT calculations of 2 a , 2 b , and 3 persistently result in the bisallylic distortion as the minimum geometry and show that the oxidation leads to a depopulation of the σ‐system of the cyclo‐E6 ligands in 2 a – 3 . Among the starting complexes, 2 c is reported for the first time including its preparation and full characterization.  相似文献   

15.
Photolytic replacement of the arene ligand in the cations [CpFe(p-xylene)]+ (Cp = C5Me5) by P(OMe)3 ligands is only possible when a sensitizer (acetone or anthracene) is present and leads to CpFe+{P(OMe3)}3. Photoextrusion of one phosphite ligand from [C5R5Fe{P(OMe)3}3]+ (R = H, Me) or of the carbonyl from [C5R5Fe(P ⌢ P)(CO)]+ (R = H, Me; P ⌢ P = dppm, dppe) in CH3CN leads to CH3CN complexes which are reversibly oxidized.  相似文献   

16.
Under irradiation dimerization of the diphosphenes CpPPCp and Cp*PPR (Cp  Pentamethylcyclopentadienyl, R  2,4,6-Tri-t-butylphenyl) and the phosphaarsene CpAsPR takes place. Further irradiation leads to homolytic cleavage of Cpelement bonds. Intramolecular recombination leads to the bicyclic butterfly-compounds P4R2 and P2As2R2.  相似文献   

17.
A series of tertiary nitriles was synthesized by alkylation of acetonitrile, primary and secondary nitriles, using alkylbromides and sodium amide in liquid ammonia. By reaction of the in situ formed organometallic Lewis acids [CpM(CO)(PPh3)]+ (M = Fe, Ru) with the novel tertiary nitriles, the complexes [CpM(CO)(PPh3)(N≡C–CR1R2R3]BF4 were obtained. A di‐iron complex was formed with 1,6‐dicyanohexane.  相似文献   

18.
Perfluoroalkyl (RF) titanocene reagents [Cp2TiIIIRF] synthesized via [Cp2TiIIICl] rather than [Cp2TiII] show new types of perfluoroalkylation reactions. The [Cp2TiIIIRF] reagents exhibit a wide variety of reactivity with carbonyl compounds including esters and nitriles, and selectivities far higher than those reported for conventional RFLi and RFMgX reagents.  相似文献   

19.
[CpR(OC)Mo(μ‐η2:2‐P2)2FeCpR′] as Educt for Heterobimetallic Dinuclear Clusters with P2 and CnRnP4‐n Ligands (n = 1, 2) The cothermolysis of [CpR(OC)Mo(μ‐η2:2‐P2)2FeCpR′] ( 1 ) and tBuC≡P ( 2 ) as well as PhC≡CPh ( 3 ) affords the heterobimetallic triple‐decker like dinuclear clusters [(Cp'''Mo)(Cp*′Fe)(P3CtBu)(P2)] ( 4 ), Cp''' = C5H2tBu3‐1,2,4, Cp*′ = C5Me4Et, and [(Cp*Mo)(Cp*Fe)(P2C2Ph2)(P2)] ( 5 ) with a bridging tri‐ and diphosphabutadiendiyl ligand. 4 and 5 have been characterized additionally by X‐ray crystallography.  相似文献   

20.
A new and selective one‐step synthesis was developed for the first activation stage of white phosphorus by organic radicals. The reactions of NaCpR with P4 in the presence of CuX or FeBr3 leads to the clean formation of organic substituted P4 butterfly compounds CpR2P4 (CpR: CpBIG=C5(4‐nBuC6H4)5 ( 1 a ), Cp′′′=C5H2tBu3 ( 1 b ), Cp*=C5Me5 ( 1 c ) und Cp4iPr=C5HiPr4 ( 1 d )). The reaction proceeds via the activation of P4 by CpR radicals mediated by transition metals. The newly formed organic derivatives of P4 have been comprehensively characterized by NMR spectroscopy and X‐ray crystallography.  相似文献   

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