The synthesis of new lanthanide allyl complexes of enhanced stability and solubility in saturated hydrocarbons based on silyl-substituted allyl ligands is reported. Thus the potassium salt K(CH2CHCHSiMe3) ( 1 ) reacts with YCl3 in tetrahydrofuran to give the tris-allyl complex Y(CH2CHCHSiMe3)3 ( 2 ), while K(CH2CHCHSiMe2tBu) ( 3 ) affords Y(CH2CHCHSiMe2tBu)3(THF)1.5 ( 4 ). Slow re-crystallization of 4 from light petroleum in the presence of tert-butylcyanide led to multiple insertion to give the sec-amido complex Y{NHC(tBu)(CH)3SiMe2tBu}2{η2-NHC(tBu)CH=CHCH2SiMe2tBu)CH(CHCHSiMe2tBu)CtBuNH}(THF)·(CH3CH(Me)(CH2)2CH3) ( 5 ), which was crystallographically characterized. The reaction of ScCl3(THF)3 with two equivalents of Li{1,3-C3H3(SiMe3)2} in tetrahydrofuran gives the bis-allyl complex {1,3-C3H3(SiMe3)2}2Sc(μ-Cl)2Li(THF)2 ( 6 ), while the analogous reaction of K{1,3-C3H3(SiMe3)2} ( 7 ) with either LaCl3 or YCl3 in tetrahydrofuran affords the bis-allyl complexes MCl{1,3-C3H3(SiMe3)2}2(THF)x (8, M = La, x = 1; 9, M = Y, x = 0). An attempt to prepare the similar neodymium complex gave the mono-allyl complex NdI2{1,3-C3H3(SiMe3)2}(THF)1.25 ( 10 ). The reactions of 8 and 9 with triisobutyl aluminum in benzene-d6 show allyl exchange between lanthanide and aluminum. Complexes 8 , 9 , and 10 have been tested with a variety of activator systems as catalysts for the polymerization of 1,3-butadiene. 相似文献
Homopolymerization of styrenic monomers (St, p-Me-St, p-tBu-St, p-tBuO-St) and their copolymerization with ethylene, with the use of [(tBu2O2NN′)ZrCl]2(μ-O) ( 1 ) and (tBu2O2NN′)TiCl2 ( 2 ), where tBu2O2NN′ = Me2N(CH2)2N(CH2-2-O−-3,5-tBu2-C6H2)2, is explored in the presence of MMAO and (iBu)3Al/Ph3CB(C6F5)4. The ethylene/styrenic monomers copolymerization with 1 /MMAO produces exclusively copolymers with high activity and good comonomer incorporation whereas the other catalytic systems yield mixtures of copolymers and homopolymers. The use of p-alkyl styrene derivatives instead of styrene raises the catalytic activity, comonomer incorporation and molecular weights of the copolymers. Complex 2 exhibits higher activity in homopolymerization of styrenic monomers than 1 irrespective of the kind of the activator employed. A clear dependence is observed for the molecular weight and catalyst activity against the kind of the styrenic monomer. The obtained polymers were atactic and only the complex 2 , when activated by MMAO, promoted the highly syndiospecific polymerization of p-Me-St and p-tBu-St. Poly(p-tBuO-St) exhibits fiber-forming properties. 相似文献
A series of 2,4,6‐trimethylbenzylidyne tungsten and molybdenum complexes was prepared from the tribromides mer‐[MesCMBr3(dme)] ( 9a , M=W; 9b , M=Mo, dme=1,2‐dimethoxyethane). Successive reaction of complexes 9 with lithium or potassium hexafluoro‐tert‐butoxide and lithium 1,3‐di‐tert‐butylimidazolin‐2‐imide, (Imt‐BuN)Li, afforded the imidazolin‐2‐iminato complexes [MesCM{OC(CF3)2Me}2(Imt‐BuN)] ( 10a , M=W; 10b , M=Mo), whereas the reactions of 9 with three equivalents of LiOSi(O‐t‐Bu)3 or KOC(CF3)3 gave [MesCM{OSi(O‐t‐Bu)3}3] ( 11a , M=W; 11b , M=Mo) and [MesCM{OC(CF3)3}3] ( 12a , M=W; 12b , M=Mo), respectively. For comparison, the benzylidyne complex [PhCMo{OSi(O‐t‐Bu)3}3] ( 7b ) was also prepared, and its molecular structure together with those of 10a , 10b , 11b , 12a and 12b were established by X‐ray diffraction analysis. Complexes 10 and 11 were employed as pre‐catalysts for the alkyne metathesis of the test substrate 3‐pentynyl benzyl ether ( 13 ) at low catalyst loadings (1 mol%) in the presence of molecular sieve (5 Å). Comparative studies of these 2,4,6‐trimethylbenzylidyne species (MesCM) with their benzylidyne analogues (PhCM) revealed that the increased steric bulk renders the former more stable and manageable in air in solid form for shorter periods of time, but at the expense of a slower initiation, which requires higher temperatures or longer reaction times.
Reaction of compound Ru(O2CCF3)(CHCHtBu)(CO)(PPh3)2 with CO gives the η1-alkeneacyl complex Ru(O2CCF3)(OCCHCHtBu)(CO)(PPh3)2, which is in equilibrium with the dicarbonyl Ru(O2CCF3)(CHCHtBu)(CO)2(PPh3)2 derivative in CH2Cl2 solution. The η1-acyl form involves an η1-coordination of the O2CCF3 ligand, whereas the dicarbonyl form contains the carboxylate ligand η2-coordinated to the metal. The same mixture of carbonylated compounds can be obtained from the reaction of Ru(CHCHtBu)Cl(CO)2(PPh3)2 with Na[O2CCF3] in a CH2Cl2/MeOH solution. These reactions reveal the significance of ancillary bidentate ligands for the η-nature of the acyl–metal bond. The molecular structure of the complex Ru(O2CCF3)(OCCHCHtBu)(CO)(PPh3)2 was established by X-ray diffraction study of a monocrystal obtained from a CH2Cl2/MeOH solution of the mixture of carbonylated compounds. 相似文献
The reaction of [{P(μ-NtBu)}2(μ-NH)}5I]−[Li(thf)4]+([1 · I]−[Li(thf)4]+) with NaOMe in CH2Cl2 gives the title compound [{P(μ-NtBu)}2(μ-NH)]5(CH2Cl2)2 [1 · (CH2Cl2)2] the first adduct containing this type of macrocyclic phosph(III)azane host and a neutral guest. 相似文献
The solvent extraction of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from weak acidic hydrochloric acid solutions into an organic phase containing 4-benzoyl-3-methyl-1-phenylpyrazol-5-one (HP) and neutral tridentate organophosphorus ligands R2P(O)CH2OCH2C(O)NBu2 R = Bu (I), R = Ph (II) and R2P(O)CH2OCH2P(O)R12 R = R1 = Bu (III); R = Bu, R1 = Ph (IV); R = R1 = Ph(V) has been studied. A considerable synergistic effect was observed in the presence of HP in the organic phase containing tetraoctyldiglycolamide (TODGA) and neutral organophosphorus ligands I - V. A successive replacement of C(O)NAlk2 groups in the diglycolamide extractant molecule by P(O)Ph2 groups leads to an increase in the extraction efficiency of Ln(III) ions when toluene was used as diluent. Phosphoryl-containing podand I possess a higher extraction efficiency towards Ln(III) ions than TODGA. The extraction equilibrium was investigated and the equilibrium constants were calculated. It was found that the lanthanide(III) ions are extracted as LnLP3 and LnL2P3 complexes with mixtures of HP and I in toluene from weak acidic solutions. 相似文献
Cationic benzyl titanium complexes [Ti(η5: η1-C5Me4SiMe2NR')-(CH2Ph)]+ were cleanly formed by the reaction of the dibenzyl titanium complexes [Ti(η5: η1-C5Me4SiMe2NR')(CH2Ph)2] with B(C6F5)3 and [Ph3C][B(C6F5)4] in bromobenzene. NMR spectroscopic studies suggest that the benzyl titanium cations contain a fluxional η2-coordinated benzyl ligand. Kinetic analysis showed that the benzyl titanium cations decompose according to first-order kinetics and that the amido substituents R' (R' = Me, iPr, tBu) in the linked amido-cyclopentadienyl ligand influence the lability of these benzyl titanium cations. The order of the kinetic stability of the benzyl titanium cations was found for both anions to follow the order R' = Me > iPr > tBu. The benzyl titanium cations generated with [Ph3C][B(C6F5)4] were found to undergo faster decomposition than those generated with B(C6F5)3. The ethylene polymerization activity order for both systems was found to be the reverse: R' = tBu > iPr > Me. The decomposition of the benzyl titanium cations was suggested to occur via C—H activation with concomitant toluene elimination. 相似文献
The reaction of phenyl(alkynyl)iodine(III) triflates with diorganoplatinum(II) complexes provides a general route for the synthesis of a new class of alkynylplatinum(IV) complexes containing PtIVR2(CCR2) groups, e.g., the 4,4′-bis(tert-butyl)-2,2′-bipyridine complexes PtIR2(CCSiMe3)(But2bpy) (R=Me, Ph); IPh2(OTf) reacts with PtPh2(But2bpy) to form the first archetypal triarylplatinum(IV) complex PtIPh3(But2bpy). 相似文献
New functionalized ionic liquids (ILs), comprised of multi-methoxyethyl substituted quaternary ammonium cations (i.e. [N(CH2CH2OCH3)4−n(R)n]+; n = 1, R = CH3OCH2CH2; n = 1, R = CH3, CH2CH3; n = 2, R = CH3CH2), and two representative perfluorinated sulfonimide anions (i.e. bis(fluorosulfonyl)imide (FSI−) and bis(trifluoromethanesulfonyl)imide (TFSI−)), were prepared. Their fundamental properties, including phase transition, thermal stability, viscosity, density, specific conductivity and electrochemical window, were extensively characterized. These multi-ether functionalized ionic liquids exhibit good capability of dissolving lithium salts. Their binary electrolytes containing high concentration of the corresponding lithium salt ([Li+] >1.6 mol kg−1) show Li+ ion transference number (tLi+) as high as 0.6-0.7. Their electrochemical stability allows Li deposition/stripping realized at room temperature. The desired properties of these multi-ether functionalized ionic liquids make them potential electrolytes for Li (or Li-ion) batteries. 相似文献
Compounds R2M[S(O)CPh] [where R?=?tBu, M?=?Al (1); R?=?tBu, M?=?Ga (2); R?=?Me, M?=?Ga (3)] have been synthesized in reactions of R3M with thiobenzoic acid in a 1:1 molar ratio of reagents. The reaction of Me3Ga with three equivalents of thiobenzoic acid yielded the compound Ga[S(O)CPh]3 (4), in which thiobenzoate moieties act as bidentate SO ligands. In the presence of Et3N, InCl3 reacted with thiobenzoic acid with formation of an ionic compound {In[S(O)CPh]4}?(HNEt3)+ (5). The thiobenzoate ligands are bonded with the metallic center via the sulfur atoms only. The compounds 4 and 5 have been structurally and thermally studied. The thermal decomposition pathways of compounds 4 and 5 are proposed. 相似文献
A series of tributyltin(IV) complexes of 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoates have been investigated by 1H, 13C, 119Sn NMR, IR and 119Sn M?ssbauer spectroscopic techniques in combination with elemental analyses. Single crystal X-ray crystallography of Bu3Sn[O2CC6H4{N=C(H)C6H3-2-OH(N=NC6H4CH3-4)}-p] reveals a distorted tetrahedral structure which is further supported by 119Sn M?ssbauer data. Toxicity studies of the tributyltin(IV) complexes along with their ligands 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acids on the second larval instar of the Anopheles stephensi mosquito larvae are also reported. 相似文献
The solvent extraction of Ln(III) ions from perchlorate aqueous solutions into an organic phase containing neutral polyfunctional organophosphorus ligands R2P(O)CH2OCH2C(O)NBu2 R = Bu (I), R = Ph (II) and R2P(O)CH2OCH2P(O)R12 R = R1 = Bu (III); R = Bu, R1 = Ph (IV); R = R1 = Ph(V) has been studied. Their extraction behavior was compared with that of tetrabutyldiglycolamide (TBDGA), tetrabutylmethylenediphosphine dioxide (VI), P,P-dibutyl-P’P’-diphenylmethylenediphosphine dioxide (VII), tetraphenylmethylenediphosphine dioxide (VIII), dibutyl-N,N-dibutylcarbamoylmethylphosphine oxide (IX) and diphenyl-N,N-dibutylcarbamoylmethylphosphine oxide (X). The extraction equilibrium was investigated, and the equilibrium constants were calculated. It was found that the lanthanide(III) ions are extracted with the studied extractants from perchlorate solutions as LnL3(ClO4)3 complexes. In the NaClO4 media, TBDGA was found to possess a higher extraction efficiency towards Ln(III) ions than other neutral donor ligands studied. A successive replacement of the C(O)NBu2 groups in the diglycolamide extractant molecule by phosphoryl ones leads to a decrease in the extraction efficiency of Ln(III) ions. In the NaClO4 media, compounds II, IV and V with phenyl radicals at the P(O) group demonstrate a lower extraction efficiency towards Ln(III) ions than their butyl-substituted analogs. In contrast, phenyl-substituted diphosphine dioxides VIII, VII and carbamoylmethylphosphine oxide (X) extract Ln(III) ions more effectively than their butyl-substituted analogs VI and IX. The extraction of Ln(III) ions from HClO4 solutions is accompanied by HClO4 interaction with neutral donor extractants, which leads to a decrease of the free extractant concentration in the organic phase. By this reason, an increase in the HClO4 concentration higher than 0.1 M is accompanied by a decrease of the Ln(III) extraction with TBDGA. In the 3 M HClO4 system, diphosphine dioxide VIII outperforms TBDGA at the Ln(III) extraction. 相似文献
Substituted Alkinyles as Axial Ligands at Hemine Like Bound Iron(III) - Incorporation into a Spectrochemical Series . Substituted lithium alkynyles Li CC R (R = tBu, Ph, p-Cl C6H4, Me3Si, iPr3Si, Ph3Si) react with the hemine like macrocyclic iron(III) complex 6,13-di(ethoxycarbonyl)-5, 14-dimethyl-1, 4, 8, 11-tetraazatetradeca-4,6,12,14-tetraenato[2−]iron(III)-iodide (formula 2 ;) in tetrahydrofuran to form anionic low-spin di-adducts [fe(CC R)2]−. The incorporation of the alkynyles into a spectrochemical series of the axial ligands (studied by the sharp equatorial-ligand-to-metal CT absorption band) results in the wavelength-sequence (nm): OH− (≈︁ 510) « N3− (≈︁ 625) < tBu CC− (664) < NH3 (666) < Ph CC− (692) < Ph NH2 (695) < Me3Si CC− (698) < SCN− (713) < Ph3Si C C− (716) < CN− (739) < 4-picoline (759) < pyridine (765) < nicotinamide (776) < methylnicotinat (788) < pyrazine (798) and points to a significant π-acceptor ability of the silyl substituents. 相似文献
6-dimethylamino-6-methylfulvene (7) was converted to the [(C5H4)–CMe2–NMe2]− ligand system (8) by treatment with methyllithium. Its reaction with MCl4 (M = Zr, Ti) followed by treatment with CH3Li gave the respective [(C5H4)–CMe2–NMe2]2M(CH3)2 complexes (12). Their reaction with B(C6F5)3 led to reactive metallocene cation complexes that instantaneously underwent CH activation at a N–CH3 group to yield the metallacyclic cation complexes 15. (tert-butylaminomethyl)fluorene was prepared by the addition of tert-butylisocyanate
to fluorenyllithium followed by hydride reduction. Deprotonation by a variety of bases gave rise to a series of competing
and consecutive reactions to yield several unusually structured products, among them a fluorenyl-anellated η5-1-azapentadienyl anion equivalent (25) and [(flu)-CH2–NCMe3]Li2 (23). An improved way of generating synthetically useful C1-linked [Cp–C1(R)n–NR1]2- dianion equivalents was developed starting from 6-amino-6-methylfulvene (26). N-silylation followed by double deprotonation
with, e.g., lithium diisopropylamide cleanly furnished the respective [(C5H4)–C(=CH2)–NSiMe3]2- dianion 33 (isolated as the dilithio derivative). Its reaction with Cl2Zr(NEt2)2 in THF gave [η5:κ-N-(C5H4)–C(=CH2)–NSiMe3]Zr(NEt2)2 36. Activation of 36 with methylalumoxane in toluene led to the formation of a C1-linked “constrained geometry” Ziegler catalyst that polymerized ethylene similarly as the [(C5Me4)SiMe2NCMe3]ZrCl2 derived literature system.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
The new imine ligand (E)-2,4,6-Me3C6H2CH2NCHtBu (1) has been prepared from 2,4,6-trimethylbenzylamine and trimethylacetaldehyde. In this imine, the ortho-positions of the benzyl group are blocked by methyl groups, and there are no β-hydrogen atoms susceptible for imine–enamine rearrangement. Thus, reaction with [PdCl2(C6H5CN)2] leads to the complex trans-[PdCl2(2,4,6-Me3C6H2CH2NCHtBu)2] (2) that cannot undergo cyclopalladation. The single-crystal X-ray structure analysis of trans-[PdCl2(2,4,6-Me3C6H2CH2NCHtBu)2] (2) confirms the trans-coordination of the imine ligands in this square-planar complex. 相似文献
We synthesized a series of four dinuclear constrained geometry catalysts (DCGCs) containing alkyl-substituted para-xylene bridges [TiCl2{N(tBu)Si(Me)2}C9H5]2[(CH2){(R)2C6H2}(CH2)]: 13 (R = hydrogen), 14 (R = isopropyl), 15 (R = n-hexyl), and 16 (R = n-octyl). The structures and compositions of the synthesized complexes were conveniently identified by 1H NMR, 13C NMR and elemental analysis (EA). In order to determine the effect of steric and electronic properties of various alkyl branches on the xylene group, ethylene homo and copolymerization experiments by use of these metallocenes have been conducted. Dow CGC ([Me2Si (μ5-Me4Cp)NtBu]TiCl2) has been used as the control catalyst for comparison. It was found that the activity of Catalyst 13 was highest and the activities of the new DCGCs were much higher than that of Dow CGC. Polyethylene having more than 1,000,000 g/mol of molecular weight that may be classified as ultra high molecular weight polyethylene (UHMWPE) has been able to be successfully produced from the new DCGCs. Most importantly it was demonstrated that the control of polymerization properties of DCGCs was determined by the nature of the alkyl substituent at para-xylene bridge. Catalyst 14 having isopropyl substituent at the bridge produced the longest polymer with the lowest catalytic activity. On the other hand, DCGCs 15 and 16 exhibited the greatest comonomer reactivity to make ethylene/styrene copolymers with the highest styrene contents. 相似文献