Oxidative addition of 2‐phenylethylbromide (PhCH2CH2Br) to dimethylplatinum(II) complexes [PtMe2(NN)] ( 1a , NN = 2,2′‐bipyridine (bpy); 1b , NN = 1,10‐phenanthroline (phen)) afforded the new organoplatinum(IV) complexes [PtMe2(Br)(PhCH2CH2)(bpy)], as a mixture of trans ( 2a ) and cis ( 3a ) isomers, and [PtMe2(Br)(PhCH2CH2)(phen)], as a mixture of trans ( 2b ) and cis ( 3b ) isomers, respectively. The new Pt(IV) complexes were readily characterized using multinuclear (1H and 13C) NMR spectroscopy and elemental microanalysis. The crystal structure of 2a was further determined using X‐ray crystallography indicating an octahedral geometry around the platinum centre. A comparison of reactivity of RCH2Br reagents (R = CH3, Ph or PhCH2) in their oxidative addition reactions with complex 1a , with an emphasis on the effects of the R groups of alkyl halides, was also conducted using density functional theory. 相似文献
Abstract Hindered rotation in alkyldithiocarbamates of the type RR′NC(= S)SR″ [R, R′, R″ = Me, Me, Et (1); PhCH2, Me, Et (2); PhCH2, H, Et (3); PhCH2, H, Me (4) and O(CH2CH2)2, Et (5)′ has been investigated using variable-temperature 1H NMR spectroscopy in CDCl3, C6D6, and DMSO-d6 solutions. Rotational parameters were calculated by the coalescence temperature method. Nitrogen substituent effects on the free energy of activation and on the equilibrium constant of unsymmetrical conformers at room temperature are discussed. 相似文献
Using 1H- and 13C-NMR spectroscopies, cationic intermediates formed by activation of L2ZrCl2 with methylaluminoxane (MAO) in toluene were monitored at Al/Zr ratios from 50 to 1000 (L2 are various cyclopentadienyl (Cp), indenyl (Ind) and fluorenyl (Flu) ligands). The following catalysts were studied: (Cp-R)2ZrCl2 (R=Me, 1,2-Me2, 1,2,3-Me3, 1,2,4-Me3, Me4, Me5, n-Bu, t-Bu), rac-ethanediyl(Ind)2ZrCl2, rac-Me2Si(Ind)2ZrCl2, rac-Me2Si(1-Ind-2-Me)2ZrCl2, rac-ethanediyl(1-Ind-4,5,6,7-H4)2ZrCl2, (Ind-2-Me)2ZrCl2, Me2C(Cp)(Flu)ZrCl2, Me2C(Cp-3-Me)(Flu)ZrCl2 and Me2Si(Flu)2ZrCl2. Correlations between spectroscopic and ethene polymerization data for catalysts (Cp-R)2ZrCl2/MAO (R=H, Me, 1,2-Me2, 1,2,3-Me3, 1,2,4-Me3, Me4, Me5, n-Bu, t-Bu) and rac-Me2Si(Ind)2ZrCl2 were established. The catalysts (Cp-R)2ZrCl2/AlMe3/CPh3+B(C6F5)4− (R=Me, 1,2-Me2, 1,2,3-Me3, 1,2,4-Me3, Me4, n-Bu, t-Bu) were also studied for comparison of spectroscopic and polymerization data with MAO-based systems. Complexes of type (Cp-R)2ZrMe+←Me−-Al≡MAO (IV) with different [Me-MAO]− counteranions have been identified in the (Cp-R)2ZrCl2/MAO (R=n-Bu, t-Bu) systems at low Al/Zr ratios (50-200). At Al/Zr ratios of 500-1000, the complex [L2Zr(μ-Me)2AlMe2]+[Me-MAO]− (III) dominates in all MAO-based reaction systems studied. Ethene polymerization activity strongly depends on the Al/Zr ratio (Al/Zr=200-1000) for the systems (Cp-R)2ZrCl2/MAO (R=H, Me, n-Bu, t-Bu), while it is virtually constant in the same range of Al/Zr ratios for the catalytic systems (Cp-R)2ZrCl2/MAO (R=1,2-Me2, 1,2,3-Me3, 1,2,4-Me3, Me4) and rac-Me2Si(Ind)2ZrCl2/MAO. The data obtained are interpreted on assumption that complex III is the main precursor of the active centers of polymerization in MAO-based systems. 相似文献
Novel η1-vinyl complexes of the type Cp(CO)(L)FeC(OMe)C(R)R′ (R = R′ = H, Me; R = H, R′ = Me; L = Me3P, Ph3P) are obtainied via methylation of the acyl complexes Cp(CO)(L)FeC(O)R (R = Me, Et, i-Pr) with MeOSO2F and subsequent deprotonation of the resulting carbene complexes [Cp(CO)(L)FeC(OMe)R]SO3F with the phosphorus ylide Me3PCH2. The same procedure can be applied for the synthesis of the pentamethylcyclopentadienyl derivative C5Me5(CO)(Me3P)FeC(OMe)CH2, while treatment of the hydroxy or siloxy carbene complexes [Cp(CO)(L)FeC(OR)Me]X (R = H, Me3Si; X = SO3CF3) with Me3CH2 results in the transfer of the oxygen bound electrophile to the ylidic carbon. Some remarkable spectroscopic properties of the new complexes are reported. 相似文献
Summary: Propylene was copolymerized with 1,4‐divinylbenzene (1,4‐DVB) using rac‐Me2Si(2‐Me‐4‐Ph‐Ind)2ZrCl2 and MAO in the presence of hydrogen. 1H NMR spectra of the obtained copolymer confirmed the successful incorporation of 1,4‐DVB. 13C NMR analysis revealed a unique copolymer structure with the incorporated 1,4‐DVB units predominantly forming 1,4‐substituted phenyl repeating units in the polymer main chain. A plausible mechanism involving spontaneous insertion of terminal styryl into Zr‐H species was proposed to rationalize the unique incorporation of 1,4‐DVB.
Copolymerization of propylene with 1,4‐divinylbenzene in the presence of hydrogen. 相似文献
Yttrocene‐carboxylate complex [Cp*2Y(OOCArMe)] (Cp*=C5Me5, ArMe=C6H2Me3‐2,4,6) was synthesized as a spectroscopically versatile model system for investigating the reactivity of alkylaluminum hydrides towards rare‐earth‐metal carboxylates. Equimolar reactions with bis‐neosilylaluminum hydride and dimethylaluminum hydride gave adduct complexes of the general formula [Cp*2Y(μ‐OOCArMe)(μ‐H)AlR2] (R=CH2SiMe3, Me). The use of an excess of the respective aluminum hydride led to the formation of product mixtures, from which the yttrium‐aluminum‐hydride complex [{Cp*2Y(μ‐H)AlMe2(μ‐H)AlMe2(μ‐CH3)}2] could be isolated, which features a 12‐membered‐ring structure. The adduct complexes [Cp*2Y(μ‐OOCArMe)(μ‐H)AlR2] display identical 1J(Y,H) coupling constants of 24.5 Hz for the bridging hydrido ligands and similar 89Y NMR shifts of δ=?88.1 ppm (R=CH2SiMe3) and δ=?86.3 ppm (R=Me) in the 89Y DEPT45 NMR experiments. 相似文献
1,2,3,4‐Tetrasubstituted cyclopentadienes and indene derivatives with identical or different substituents were obtained in good to excellent isolated yields through a zirconocene‐ and CuCl‐mediated intermolecular coupling process. This synthetic procedure involved three organic partners, including one CH2I2, and two different or identical alkynes. Two alkynes or one diyne undergo Cp2ZrII‐mediated (Cp=η5‐C5H5) pair‐selective reductive coupling to afford the corresponding zirconacyclopentadiene derivatives, which react, in the presence of CuCl and 1,3‐dimethyl‐3,4,5,6‐tetrahydro‐2(1 H)‐pyrimidinone (DMPU), with CH2I2 through intermolecular followed by intramolecular coupling to afford the cyclopentadiene derivatives. An application of the prepared tetrasubstituted cyclopentadiene derivatives was demonstrated by the facile synthesis of the corresponding zirconocene complexes [(4RCp)2ZrCl2] and [(4RCp)2ZrR′2] (R′=Me, Et, or nBu). The unique 1,2,3,4‐tetrasubstituted cyclopentadiene ligands and the corresponding metallocenes are expected to have further applications in organometallic chemistry and organic synthesis. 相似文献
Reaction of [Au(DAPTA)(Cl)] with RaaiR’ in CH2Cl2 medium following ligand addition leads to [Au(DAPTA)(RaaiR’)](Cl) [DAPTA=diacetyl-1,3,5-triaza-7-phosphaadamantane, RaaiR’=p-R-C6H4-N=N- C3H2-NN-1-R’, (1—3), abbreviated as N,N’-chelator, where N(imidazole) and N(azo) represent N and N’, respectively; R=H (a), Me (b), Cl (c) and R’=Me (1), CH2CH3 (2), CH2Ph (3)]. The 1H NMR spectral measurements in D2O suggest methylene, CH2, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph it shows AB type quartets. 13C NMR spectrum in D2O suggest the molecular skeleton. The 1H-1H COSY spectrum in D2O as well as contour peaks in the 1H-13C HMQC spectrum in D2O assign the solution structure. 相似文献
A study of the coordination chemistry of different amidato ligands [(R)N?C(Ph)O] (R=Ph, 2,6‐diisopropylphenyl (Dipp)) at Group 4 metallocenes is presented. The heterometallacyclic complexes [Cp2M(Cl){κ2‐N,O‐(R)N?C(Ph)O}] M=Zr, R=Dipp ( 1 a ), Ph ( 1 b ); M=Hf, R=Ph ( 2 )) were synthesized by reaction of [Cp2MCl2] with the corresponding deprotonated amides. Complex 1 a was also prepared by direct deprotonation of the amide with Schwartz reagent [Cp2Zr(H)Cl]. Salt metathesis reaction of [Cp2Zr(H)Cl] with deprotonated amide [(Dipp)N?C(Ph)O] gave the zirconocene hydrido complex [Cp2M(H){κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 3 ). Reaction of 1 a with Mg did not result in the desired Zr(III) complex but in formation of Mg complex [(py)3Mg(Cl) {κ2‐N,O‐(Dipp)N?C(Ph)O}] ( 4 ; py=pyridine). The paramagnetic complexes [Cp′2Ti{κ2‐N,O‐(R)N?C(Ph)O}] (Cp′=Cp, R=Ph ( 7 a ); Cp′=Cp, R=Dipp ( 7 b ); Cp′=Cp*, R=Ph ( 8 )) were prepared by the reaction of the known titanocene alkyne complexes [Cp2′Ti(η2‐Me3SiC2SiMe3)] (Cp′=Cp ( 5 ), Cp′=Cp* ( 6 )) with the corresponding amides. Complexes 1 a , 2 , 3 , 4 , 7 a , 7 b , and 8 were characterized by X‐ray crystallography. The structure and bonding of complexes 7 a and 8 were also characterized by EPR spectroscopy. 相似文献