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1.
The branched triphosphanyltetrasilane PhSi(SiMe2PH2)3 ( 1 ) could be obtained in a three‐stage synthesis. It was characterised by multi‐nuclear NMR spectroscopy, mass spectrometry and IR spectroscopy. Deprotonation of 1 with GaiPr3 or [M{N(SiMe3)2}2(thf)2] (M = Ca, Sr, Ba) yields new phosphorus bridged polynuclear complexes of these metals with phosphorus atoms connected through tetrasilane fragments. While trinuclear complexes with single deprotonated phosphanyl groups could be obtained from the reactions of 1 with GaiPr3, calcium or barium silazanide (compounds 2 , 3 and 5 ), the tetranuclear complex [Sr4{PhSi(SiMe2PH)2(SiMe2P)}2(dme)6] ( 4 ) was formed in the reaction of 1 with strontium silazanide. In this compound, two of six phosphorus atoms are deprotonated twice. Compounds 2 – 5 were characterised by single‐crystal X‐ray diffraction, elemental analysis as well as IR spectroscopy and as far as possible by NMR spectroscopic techniques.  相似文献   

2.
We report on the synthesis of new derivatives of silylated clusters of the type [Ge9(SiR3)3]? (R = SiMe3, Me = CH3; R = Ph, Ph = C6H5) as well as on their reactivity towards copper and zinc compounds. The silylated cluster compounds were synthesized by heterogeneous reactions starting from the Zintl phase K4Ge9. Reaction of K[Ge9{Si(SiMe3)3}3] with ZnCl2 leads to the already known dimeric compound [Zn(Ge9{Si(SiMe3)3}3)2] ( 1 ), whereas upon the reaction with [ZnCp*2] the coordination of [ZnCp*]+ to the cluster takes place (Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl) under the formation of [ZnCp*(Ge9{Si(SiMe3)3}3)] ( 2 ). A similar reaction leads to [CuPiPr3(Ge9{Si(SiMe3)3}3)] ( 3 ) from [CuPiPr3Cl] (iPr=isopropyl). Further we investigated the novel silylated cluster units [Ge9(SiPh3)3]? ( 4 ) and [Ge9(SiPh3)2]? ( 5 ), which could be identified by mass spectroscopy. Bis‐ and tris‐silylated species can be synthesized by the respective stoichiometric reactions, and the products were characterized by ESI‐MS and NMR experiments. These clusters show rather different reactivity. The reaction of the tris‐silylated anion 4 with [CuPiPr3Cl] leads to [(CuPiPr3)3Ge9(SiPh3)2]+ as shown from NMR experiments and to [(CuPiPr3)4{Ge9(SiPh3)2}2] ( 6 ), which was characterized by single‐crystal X‐ray diffraction. Compound 6 shows a new type of coordination of the Cu atoms to the silylated Zintl clusters.  相似文献   

3.
Synthesis and Structures of Sr6P8 Polyhedra in Mixed Phosphanides/Phosphandiides of Strontium The strontiation of H2PSiiPr3 ( 1 ) with (THF)2Sr[N(SiMe3)2]2 in THF yields colorless tetrakis(tetrahydrofuran‐O)strontium bis(triisopropylsilylphosphanide) ( 3 ). The central alkaline earth metal atom has an octahedral environment with the phosphanide ligands in trans position. The homometalation in toluene leads to the elimination of 1 and THF. Cooling of this solution gives crystals of colorless tetrakis(tetrahydrofuran‐O)hexastrontium‐tetrakis(triisopropylsilylphosphanide)‐tetrakis(triisopropylsilylphosphandiide) ( 4 ). The equimolar reaction of H2PSitBu3 ( 2 ) with (THF)2Sr[N(SiMe3)2]2 in toluene yields in the first step heteroleptic dimeric {(Me3Si)2NSr(THF)2[P(H)SitBu3]}2 ( 5 )2. This compounds monomerizes in THF to (Me3Si)2N–Sr(THF)4[P(H)SitBu3] ( 6 ), which forms an equilibrium with the homoleptic dismutation products (THF)2Sr[N(SiMe3)2]2 and (THF)4Sr[P(H)SitBu3]2 ( 7 ). Compound ( 5 )2 undergoes a intramolecular strontiation and bis(tetrahydrofuran‐O)hexastrontium‐tetrakis[tri(tert‐butyl)silylphosphanide]‐tetrakis[tri(tert‐butyl)silylphosphandiide] ( 8 ) is isolated. The central Sr6P8‐polyhedra of 4 and 8 are very similar.  相似文献   

4.
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.  相似文献   

5.
The reactions of the diphosphanylsiloxane O(SiiPr2PH2)2 (1) with MiPr3 (M = Ga, In) produced the polycyclic compounds [O{SiiPr2(PH)MiPr2}{SiiPr2(P)MiPr}] 2 (2, 3). Compounds 2 and 3 are composed of three M2P2 rings forming a ladder structure and two OSi2P2M rings. By reactions of 1 with n-BuLi the polymeric compound [O(SiiPr2PHLi)2(THF)(TMEDA)] · THF (4) was obtained.  相似文献   

6.
Reactions of Zinc and Cadmium Halides with Tris(trimethylsilyl)phosphane and Tris(trimethylsilyl)arsane ZnCl2 reacts with E(SiMe3)3 (E = P, As) in toluene in the presence of PnPr3 to give the binuclear complexes [Zn2Cl2{E(SiMe3)2}2(PnPr3)2] · C7H8 (E = P 1 , As 2 ). Therefore by the use of PiPr3 clusters consisting of ten metal atoms are obtained, [Zn10Cl12(ESiMe3)4(PiPr3)4] (E = P 3 , As 4 ). As a result of the reaction of CdBr2 with P(SiMe3)3 the compound [CdBr2{P(SiMe3)3}]2 ( 5 ) can be isolated at –40 °C. In the presence of PnPr3 CdBr2 reacts with P(SiMe3)3 forming the binuclear complex [Cd2Br2{P(SiMe3)2}2(PnPr3)2] · thf ( 6 ). The same reaction with PiPr3 yields to the cluster [Cd10Br12(PSiMe3)4{P(SiMe3)3}4] · 2 C7H8 ( 7 ). ZnI2 and CdI2 react with As(SiMe3)3 to yield the complexes [MI2{As(SiMe3)3}]2 (M = Zn 8 , Cd 9 ). In the case of CdI2 additionally the cluster [Cd10I12(AsSiMe3)4 · {As(SiMe3)3}4] · 4,5 C7H8 ( 10 ) is formed which is analogous to the compounds 3 , 4 and 7 . In the presence of [PnBu4]I 8  reacts in THF to give the ionic compound [PnBu4]2[Zn6I6(AsSiMe3)4(thf)2] · C6H6 ( 11 ).  相似文献   

7.
Three new complexes with phosphanylphosphido ligands, [Cu4{μ2‐P(SiMe3)‐PtBu}4] ( 1 ), [Ag4{μ2‐P(SiMe3)‐PtBu2}4] ( 2 ) and [Cu{η1‐P(SiMe3)‐PiPr2}2]–[Li(Diglyme)2]+ ( 3 ) were synthesized and structurally characterized by X‐ray diffraction, NMR spectroscopy, and elemental analysis. Complexes 1 and 2 were obtained in the reactions of lithium derivative of diphosphane tBu2P‐P(SiMe3)Li · 2.7THF with CuCl and [iBu3PAgCl]4, respectively. The X‐ray diffraction analysis revealed that the complexes 1 and 2 present macrocyclic, tetrameric form with Cu4P4 and Ag4P4 core. Complex 3 was prepared in the reaction of CuCl with a different derivative of lithiated diphosphane iPr2P‐P(SiMe3)Li · 2(Diglyme). Surprisingly, the X‐ray analysis of 3 revealed that in this reaction instead of the tetramer the monomeric form, ionic complex [Cu{η1‐P(SiMe3)‐PiPr2}2]–[Li(Diglyme)2]+ was formed.  相似文献   

8.
Syntheses and Crystal Structures of Chalcogenido‐bridged Nickel Cluster Compounds [Ni5Se4Cl2(PPhEt2)6], [Ni12Se12(PnPr3)6], and [Ni18S18(PiPr3)6] The reaction of (R)ESiMe3 (R = SiMe3, Mes = C9H11; E = S, Se) with [NiCl2(PPhEt2)2] and [NiCl2(PR3)2] (R = nPr, iPr) gives new chalcogenido‐bridged nickel cluster compounds [Ni5Se4Cl2(PPhEt2)6]·2THF ( 1 ), [Ni12Se12(PnPr3)6]·2THF ( 2 ), and [Ni18S18(PiPr3)6]·2THF ( 3 ). The structures of these compounds were determined by single crystal X‐ray structural analyses.  相似文献   

9.
Direct treatment of HOdbp (= 2,6-dibenzylphenol) with strontium or barium metal in the absence of solvent at high temperature provides the corresponding phenolates Sr(Odbp)2 and Ba(Odbp)2. Recrystallisation of Ba(Odbp)2 from THF gave a good yield of the crystalline dimer [Ba(Odbp)2(THF)]2 · 2THF. Attempted recrystallisation of Sr(Odbp)2 from THF mostly yielded microcrystalline material characterized as [Sr(Odbp)2]n but on one occasion gave a small crop of crystalline [Sr9(Odbp)8(O2SiMe2)4(OH)2(THF)6(OH2)2] · 6THF derived from the adventitious reaction of Sr(Odbp)2 with dimethylsilicone grease ({OSiMe2}∞). In the solid-state [Ba(Odbp)2(THF)]2 · 2THF displays significant intramolecular Ba?π-arene interactions with the pendant benzyl substituents. [Sr9(Odbp)8(O2SiMe2)4(OH)2(THF)6(OH2)2] · 6THF features a square prismatic [Sr(O2SiMe2)4]6− core capped by two inverse crown-like square [Sr4(Odbp)4(OH)(L)4]3+ units, where L = OH2 or THF, that are staggered with respect to the cuboidal core.  相似文献   

10.
Nanosheet compounds Pd11(SiiPr)2(SiiPr2)4(CNtBu)10 ( 1 ) and Pd11(SiiPr)2(SiiPr2)4(CNMes)10 ( 2 ), containing two Pd7(SiiPr)(SiiPr2)2(CNR)4 plates (R=tBu or Mes) connected with three common Pd atoms, were investigated with DFT method. All Pd atoms are somewhat positively charged and the electron density is accumulated between the Pd and Si atoms, indicating that a charge transfer (CT) occurs from the Pd to the Si atoms of the SiMe2 and SiMe groups. Negative regions of the Laplacian of the electron density were found between the Pd and Si atoms. A model of a seven‐coordinated Si species, that is, Pd5(Pd?SiMe), is predicted to be a stable pentagonal bipyramidal molecule. Five Pd atoms in the equatorial plane form bonding overlaps with two 3p orbitals of the Si atom. This is a new type of hypervalency. The Ge analogues have geometry and an electronic structure similar to those of the Si compounds. But their formation energies are smaller than those of the Si analogues. The use of the element Si is crucial to synthesize these nanoplate compounds.  相似文献   

11.
Synthesis and Dynamic Behaviour of [Rh2(μ-H)3H2(PiPr3)4]+. Contributions to the Reactivity of the Tetrahydridodirhodium Complex [Rh2H4(PiPr3)4] An improved synthesis of [Rh2H4(PiPr3)4] ( 2 ) from [Rh(η3-C3H5)(PiPr3)2] ( 1 ) or [Rh(η3-CH2C6H5)(PiPr3)2] ( 3 ) and H2 is described. Compound 2 reacts with CO or CH3OH to give trans-[RhH(CO)(PiPr3)2] ( 4 ) and with ethene/acetone to yield a mixture of 4 and trans-[RhCH3(CO)(PiPr3)2] ( 5 ). The carbonyl(methyl) complex 5 has also been prepared from trans-[RhCl(CO)(PiPr3)2] ( 6 ) and CH3MgI. Whereas the reaction of 2 with two parts of CF3CO2H leads to [RhH2(η2-O2CCF3) · (PiPr3)2] ( 8 ), treatment of 2 with one equivalent of CF3CO2H in presence of NH4PF6 gives the dinuclear compound [Rh2H5(PiPr3)4]PF6 ( 9a ). The reactions of 2 with HBF4 and [NO]BF4 afford the complexes [Rh2H5(PiPr3)4]BF4 ( 9b ) and trans-[RhF(NO)(PiPr3)2]BF4 ( 11 ), respectively. In solution, the cation [Rh2(μ-H)3H2(PiPr3)4]+ of the compounds 9a and 9b undergoes an intramolecular rearrangement in which the bridging hydrido and the phosphane ligands are involved.  相似文献   

12.
Alkaline‐earth (most prominently barium) complexes of the type [Ae{N(SiMe3)2}2?(THF)x] and [{N^N}Ae{N(SiMe3)2}?(THF)x] are very active and productive precatalysts (TON=396, TOF up to 3600 h?1; Ca相似文献   

13.
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 CYlide−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.  相似文献   

14.
Reaction of the PH2‐transfer reagent Si(PH2)4 ( 1 ) with SiCl4 affords a mixture of the ClnSi(PH2)4–n compounds ( 2 a , n = 1), ( 2 b , n = 2), and ( 2 c , n = 3) which were characterized by 1H‐31P‐COSY NMR spectroscopy. The formation of ( 2 a ) is drastically accelerated by using GeCl4 instead of SiCl4 as PH2 acceptor, but a stable molecular GeCl4–n(PH2)n containing product could not be obtained. In contrast, conversion of (C6F5)3GeCl with Si(PH2)4 ( 1 ) furnishes 2 a but also the remarkably stable tris(pentafluorophenyl)phosphaneylgermane ( 3 ). The latter is isolated in the form of colorless crystals in 97% yield and represents the first PH2‐substituted germane being structurally characterized by single‐crystal X‐ray diffraction. Protolysis of 1 with MeOH and PhOH occurs relatively fast and leads to mixtures of compounds of the type (RO)nSi(PH2)4–n ( 4 , n = 1), ( 5 , n = 2), and ( 6 , n = 3). The sterically congested phenols MesOH and 3,5‐Me2PhOH react with 1 only to the respective mono‐ and disubstituted silylphosphanes ( 4 c , d ) and ( 5 c , d ), respectively; 4 c and 4 d were isolated by fractional condensation in the form of air‐ and moisture‐sensitive oils. Lithiation of 1 with four molar equiv. of LiNiPr2 in THF/Et2O at –80 °C, surprisingly, leads to insoluble Si(PHLi)4 ( 8 a ) which was tetrasilylated with iPr3SiOSO2CF3, affording the tetrakis(triisopropylsilylphosphaneyl)silane ( 8 b ). However, attempts to achieve the tetralithiation of the P atoms in 8 b through reaction with four molar equiv. BuLi leads to the unexpected cluster formation of butyl‐tris[lithium(triisopropylsilyl)phosphanideyl] silane‐dimer ( 9 ) in 30% yield and LiPHSiiPr3; compound 9 consists of a Li6P6Si2 cluster framework.  相似文献   

15.
Diisobutyl(phosphaneyl)alane: a Simple PH2‐Transfer Reagent for the Synthesis of Polyphosphaneyl Compounds of Silicon and Germanium Introduction of PH3 into a solution of diisobutylaluminium hydride in hexane furnishes, under evolution of H2, the title compound [iBu2AlPH2]3 ( 4 ). The alane 4 is probably trimer in noncoordinating solvents such as hydrocarbons and shows only a marginal tendency in such solutions to undergo dissociation. A nucleophilic transfer of the PH2 group in 4 onto E–X‐compounds of group 14 elements (E = Si, Ge; X = Cl) succeeds only in the presence of THF which transforms 4 to the corresponding monomeric, THF‐solvated alane 5 . The latter is a remarkable mild phosphaneylation reagent, which facilitates access to Si(PH2)4 ( 1 ), Ge(PH2)4 ( 2 ), MeSi(PH2)3 ( 6 ), and EtSi(PH2)3 ( 7 ) more efficiently.  相似文献   

16.
Amido Metalates of Rare Earth Elements. Syntheses and Crystal Structures of [Na(12-crown-4)2][M{N(SiMe3)2}3(OSiMe3)] (M = Sm, Yb), [Na(THF)3Sm{N(SiMe3)2}3(C≡C–Ph)], [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3){N(SiMe3)2}4], and of [NaN(SiMe3)2(THF)]2. Applications of Rare Earth Metal Complexes as Polymerization Catalysts The amido silyloxy complexes [Na(12-crown-4)2][M{N(SiMe3)2}3(OSiMe3)] with M = Sm ( 1 a ), Eu ( 1 b ), Yb ( 1 c ), and Lu ( 1 d ) were obtained from the trisamides M[N(SiMe3)3]3 and NaOSiMe3 in n-hexane in the presence of 12-crown-4; they form yellow to orange-red crystals, of which 1 a and 1 c were characterized crystallographically. The complexes crystallize isotypically with one another in the monoclinic space group I2/a with eight formula units per unit cell. The metal atoms of the complex anions are tetrahedrally coordinated by the three nitrogen atoms of the N(SiMe3)2– ligands and by the oxygen atom of the OSiMe3– ligand. With 172.4° for 1 a and 179.3° for 1 c the bond angles M–O–Si are practically linear. With ethynylbenzene in the presence of NaN(SiMe3)2 in tetrahydrofuran the trisamides M[N(SiMe3)2]3 react under formation of the complexes [Na(THF)3M{N(SiMe3)2}3 · (C≡C–Ph)] with M = Ce ( 2 a ), Sm ( 2 b ), and Eu ( 2 c ), of which 2 b was characterized crystallographically (monoclinic, space group P21/n, Z = 4). 2 b forms an ion pair in which the terminal carbon atom of the C≡C–Ph– ligand is connected with the samarium atom of the Sm[N(SiMe3)2]3 group and the sodium ion is side-on connected with the acetylido group. According to the crystal structure determination (space group P212121, Z = 4) [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3) · {N(SiMe3)2}4] ( 3 ), which is formed as a by-product, consists of [Na(THF)6]+ ions and dimeric anions, in which the lutetium atoms are connected to form a planar Lu2N2 four-membered ring via a μ-NH2 bridge with average Lu–N distances of 227.2 pm and via a μ-NSiMe3 bridge of average Lu–N distances of 218.5 pm. According to the crystal structure determination (space group P 1, Z = 1) [NaN(SiMe3)2(THF)]2 ( 4 ) forms centrosymmetric dimeric molecules with Na–N distances of the Na2N2 four-membered ring of 239.9 pm and distances Na–O of the terminally bonded THF molecules which are 226.7 pm. The vinylic polymerization of methylmethacrylate (MMA) catalyzed by 1 c resulted in high molecular weight polymethylmethacrylate (PMMA) with moderate yields. The reaction of 1 a or 2 b with MMA did not give PMMA. Insoluble polynorbornene was obtained in low yields by reaction of norbornene/methylaluminoxane (MAO) with 1 a , 1 c , or 2 b . The ring opening polymerization of ϵ-caprolacton or δ-valerolacton catalyzed by 2 b resulted in corresponding polylactones in quantitative yields.  相似文献   

17.
Synthesis of a Hexanuclear Calcium–Phosphorus‐Cage The metalation of tri(tert‐butyl)silylphosphane with calcium bis[bis(trimethylsilyl)amide] yields the dimer {(Me3Si)2N–Ca(THF)[μ‐P(H)SitBu3]}2 ( 1 ). In THF monomerization occurs and dismutation reactions lead to the homoleptic compounds, namely (THF)2Ca[N(SiMe3)2]2 and (THF)4Ca[P(H)SitBu3]2. In toluene, 1 undergoes dismutation reactions, bis(tetrahydrofuran)calcium bis[bis(trimethylsilyl)amide] is regained and [(Me3Si)2N–Ca(THF)]2Ca[P(H)SitBu3]4 ( 2 ) precipitates. At raised temperatures, 2 undergoes a homometallic metalation with the loss of two equivalents of HN(SiMe3)2 and dimerizes. The thus formed cage compound (THF)2Ca6[PSitBu3]4[P(H)SitBu3]4 ( 3 ) with a central Ca4P4 heterocubane moiety crystallizes upon cooling of the toluene solution. The molecular structures of 2 and 3 were determined.  相似文献   

18.
Alkane elimination reaction between Ln(CH2SiMe3)3(THF)2 (Ln = Y, Lu) with one equivalent of the amidines with different steric demanding HL ([CyC(N-2,6-iPr2C6H3)2]H (HL1), [CyC(N-2,6-Me2C6H3)2]H (HL2), [PhC(N-2,6-Me2C6H3)2]H (HL3)) in THF afforded a series of mono(amidinate) rare earth metal bis(alkyl) complexes [CyC(N-2,6-iPr2C6H3)2]Ln(CH2SiMe3)2(THF) (Ln = Y (1), Lu (3)), [CyC(N-2,6-Me2C6H3)2]Ln(CH2SiMe3)2(THF)2 (Ln = Y (4), Lu (6)), and [PhC(N-2,6-Me2C6H3)2]Y(CH2SiMe3)2(THF)2 (7) in 75–89% isolated yields. For the early lanthanide metal Nd, THF slurry of NdCl3 was stirred with three equiv of LiCH2SiMe3 in THF, followed by addition of one equiv of the amidines HL1 or HL2 gave an “ate” complex [CyC(N-2,6-iPr2C6H3)2]Nd(CH2SiMe3)2(μ-Cl)Li(THF)3 (2) in 48% yield and a neutral [CyC(N-2,6-Me2C6H3)2]Nd(CH2SiMe3)2(THF)2 (5) in 52% yield, respectively. They were characterized by elemental analysis, FT-IR, NMR spectroscopy (except for 2 and 5 for their strong paramagnetic property). Complexes 2, 3, 4 and 5 were subjected to X-ray single crystal structure determination. These neutral mono(amidinate) rare earth metal bis(alkyl) complexes showed activity towards l-lactide polymerization to give high molecular weight and narrow molecular weight distribution polymers.  相似文献   

19.
Heteroleptic silylamido complexes of the heavier alkaline earth elements calcium and strontium containing the highly fluorinated 3‐phenyl hydrotris(indazolyl)borate {F12‐Tp4Bo, 3Ph}? ligand have been synthesized by using salt metathesis reactions. The homoleptic precursors [Ae{N(SiMe3)2}2] (Ae=Ca, Sr) were treated with [Tl(F12‐Tp4Bo, 3Ph)] in pentane to form the corresponding heteroleptic complexes [(F12‐Tp4Bo, 3Ph)Ae{N(SiMe3)2}] (Ae=Ca ( 1 ); Sr ( 3 )). Compounds 1 and 3 are inert towards intermolecular redistribution. The molecular structures of 1 and 3 have been determined by using X‐ray diffraction. Compound 3 exhibits a Sr ??? MeSi agostic distortion. The synthesis of the homoleptic THF‐free compound [Ca{N(SiMe2H)2}2] ( 4 ) by transamination reaction between [Ca{N(SiMe3)2}2] and HN(SiMe2H)2 is also reported. This precursor constitutes a convenient starting material for the subsequent preparation of the THF‐free complex [(F12‐Tp4Bo, 3Ph)Ca{N(SiMe2H)2}] ( 5 ). Compound 5 is stabilized in the solid state by a Ca???β‐Si?H agostic interaction. Complexes 1 and 3 have been used as precatalysts for the intramolecular hydroamination of 2,2‐dimethylpent‐4‐en‐1‐amine. Compound 1 is highly active, converting completely 200 equivalents of aminoalkene in 16 min with 0.50 mol % catalyst loading at 25 °C.  相似文献   

20.
Methoxy‐modified β‐diimines HL 1 and HL 2 reacted with Y(CH2SiMe3)3(THF)2 to afford the corresponding bis(alkyl)s [L1Y(CH2SiMe3)2] ( 1 ) and [L2Y(CH2SiMe3)2] ( 2 ), respectively. Amination of 1 with 2,6‐diisopropyl aniline gave the bis(amido) counterpart [L1Y{N(H)(2,6‐iPr2? C6H3)}2] ( 3 ), selectively. Treatment of Y(CH2SiMe3)3(THF)2 with methoxy‐modified anilido imine HL 3 yielded bis(alkyl) complex [L3Y(CH2SiMe3)2(THF)] ( 4 ) that sequentially reacted with 2,6‐diisopropyl aniline to give the bis(amido) analogue [L3Y{N(H)(2,6‐iPr2? C6H3)}2] ( 5 ). Complex 2 was “base‐free” monomer, in which the tetradentate β‐diiminato ligand was meridional with the two alkyl species locating above and below it, generating tetragonal bipyramidal core about the metal center. Complex 3 was asymmetric monomer containing trigonal bipyramidal core with trans‐arrangement of the amido ligands. In contrast, the two cis‐located alkyl species in complex 4 were endo and exo towards the O,N,N tridentate anilido‐imido moiety. The bis(amido) complex 5 was confirmed to be structural analogue to 4 albeit without THF coordination. All these yttrium complexes are highly active initiators for the ring‐opening polymerization of L ‐LA at room temperature. The catalytic activity of the complexes and their “single‐site” or “double‐site” behavior depend on the ligand framework and the geometry of the alkyl (amido) species in the corresponding complexes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5662–5672, 2007  相似文献   

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