Zirconium Dichloride Complexes Research Articles

Unbridged 1- and 2-substituted bis(silylindenyl) zirconium(IV) and hafnium(IV) dichloride complexes as catalyst precursors for ethylene polymerization

Twelve unbridged metallocene dichloride complexes of the types [1-(4-XC6H4SiMe2)-η5-Ind]2MCl2 and [2-(4-XC6H4SiMe2)-η5-Ind]2MCl2 (X=Me, MeO, F; M=Zr, Hf) with differently 1- and 2-substituted indenyl ligands have been synthesized, characterized and applied for catalytic ethylene polymerization. After activation with methylaluminoxane (MAO), all complexes are catalysts for ethylene polymerization. However, in nearly all cases, the species with the silyl substituent in the 1-position show much higher activities than those with the same substituent in 2-position of the indenyl moiety. For instance, the MAO activated complex bis(η5-1-(dimethyl-4-tolylsilyl)idenyl) zirconium(IV) dichloride (3), displayed an almost five times higher activity (3980kg PE/mol cat.h) than the isomeric bis(η5-2-(dimethyl-4-tolylsilyl)indenyl) zirconium(IV) dichloride (19)/MAO catalyst (870kg PE/mol cat.h). The same trend was observed for the para-fluorophenyl silyl indenyl complexes 23 and 17. This behavior may be explained in a way that the same silyl substituent in position 2 can exert more steric hindrance around the metal center compared to the 1-substituted analogues. The GPC characterization of the produced polyethylenes showed that some of the resins have a bimodal molecular weight distribution indicating at least two different active sites that are involved in the polymerization process.

Zirconium dichloride complexes with bulky ω-9-methylfluorenylalkyl substituted indenyl ligands as catalysts for homogeneous ethylene polymerization

The synthesis and characterization of four new zirconium complexes with bulky ω-9-methylfluorenylalkyl substituted indenyl ligands are reported. After activation with methylaluminoxane (MAO) they can be applied as highly active catalysts for ethylene polymerization. The activities of the catalysts depend on the length of the CH2-spacer chain between the indenyl and the 9-methylfluorenyl moieties. The best results were obtained with four CH2 groups. This speaks for a comparatively free catalyst cation allowing easy coordination of the monomer to the active site and unhindered growth of the polymer chain.

Dissymmetric Bis ( Indenyl ) Zirconium Dichloride Complexes as Catalyst Precursors for Homogeneous Ethylene Polymerization

Dissymmetric Bis ( Indenyl ) Zirconium Dichloride Complexes as Catalyst Precursors for Homogeneous Ethylene Polymerization

ω-Phenoxyalkyl substituted bis(indenyl)zirconium dichloride complexes as catalysts for homogeneous ethylene polymerization

Nine bis(indenyl)zirconium dichloride complexes of the type [C9H6-(CH2)n-O-Ar]2ZrCl2 (n=3–5; Ar=Ph, t-Bu-Ph) were synthesized, characterized, activated with methylalumoxane (MAO) and tested for ethylene polymerization. Structure–property-relationship studies showed that the activities of the catalysts depend on the length of the bridging chain between the indenyl and the phenoxy group as well as on the bulk at the phenoxy substituent. A t-Bu substituent at the ortho position of the phenoxy group (5a/MAO) gives a much higher catalyst activity (27,500kgPE/molcath) than the isomer 8a/MAO with a t-Bu substituent at the para position of the phenoxy group (16,700kgPE/molcath). Obviously substituents in the ortho position of the phenyl ring generate a bulkier catalyst cation and this can keep the MAO anion at a further distance to allow easier ethylene coordination and chain growth in the polymerization steps. The mono substituted bis(indenyl) complex (C9H7)[C9H6-(CH2)4-O-4-t-Bu]ZrCl2 shows lower activity (11,700kgPE/molcath) than 8a indicating that the electronic effect is dominating in this type of catalysts.

Polymerization of propylene promoted by zirconium benzamidinates

New bis(N,N-trimethylsilylarylamidinate) zirconium dichloride complexes with various carbon substituents were prepared, and their solid as well as solution state structures were studied. In the polymerization of propylene, after activation by MAO, these catalysts provided two fractions. Ether soluble polymers were obtained at a low activity as sticky polymers with lower molecular weights, except with the o-OMe substituted complex. The solid fractions were composed of a highly isotactic polymer and a moderately syndiotactic polymer. An interesting linear correlation was found between the rates of the 2,1 and 3,1 insertions for the ether soluble fractions.

Titanium(4+) and zirconium(4+) dichloride complexes with pyridinedicarboxylic acid derivatives as ethylene polymerization catalysts

Titanium(4+) and zirconium(4+) complexes with pyridinedicarboxylic acid derivatives have been synthesized. The composition and structure of the synthesized 2,6-bis(diphenylhydroxymethyl)pyridine complexes have been corroborated by NMR and IR spectroscopy, and elemental analysis. The complexes activated with methylaluminoxane (MAO) are catalytically active in ethylene polymerization, Depending on the Ti/AlMAO ratio, the catalytic activity of the complexes varies between 90 and 420 kg PE/mol Ti h atm.

Zirconium Complexes Containing Tetradentate O,P,P,O Ligands: Ethylene and Propylene Polymerization Studies

The synthesis of a series of zirconium complexes bearing a linear diphosphanyl-bisphenoxide O,P,P,O ligand is described. The diphosphanyl-bisphenol proligand was prepared from Ph(Cl)PC2H4P(Cl)Ph as a 1:1 mixture of rac and meso diastereomers, which could be separated as a result of their differing solubilities in methanol. A relatively low barrier to phosphine inversion (ΔG⧧373K = 28.02(3) kcal/mol) allows interconversion of the two isomers. The zirconium dichloride complex of each diastereomer was prepared via treatment of ZrCl4(THF)2 with the sodium (rac) or lithium (meso) salt of the respective bisphenol. Crystallographic and NMR analyses revealed a cis-α structure for the complex bearing the rac-O,P,P,O ligand and a seven-coordinate quasi-cis-β structure for the complex derived from the meso-O,P,P,O ligand. Dibenzyl complexes were synthesized by treatment of Zr(CH2Ph)4 with the rac and meso bisphenols; NMR evidence revealed cis-α and fluxional cis-β structures, respectively. Reactions of the dibenzyl ...

Titanium and Zirconium Complexes for Polymerization of Propylene and Cyclic Esters

The new group IV complexes ((CH3)3CCOCHCONEt2)2Ti(OMe)2 (3), ((CH3)3CCOCHCONMe2)2Ti(OMe)2 (4), (CH3COCHCONMe2)2Ti(OC(CH3)3)2 (5), and ((CH3)3CCOCHCONEt2)2ZrCl2 (6) were synthesized and characterized. The titanium dialkoxide complexes 3−5 were produced during the attempts to synthesize the corresponding titanium diamido complexes via an intramolecular metathesis. A mechanism for the intramolecular metathesis is presented. Complexes 3 and 4 exhibit dynamic behavior in solution as a function of temperature. This dynamic behavior is due to a disconnection and recoordination of the β-ketoamidate chelating ligands through the weaker Ti−O bond, resulting in the formation of different octahedral stereoisomers in solution. Complexes 3−6, activated with MAO, were found to be active in the polymerization of propylene, producing elastomeric polypropylene. The elastomeric properties of the polymers obtained using complex 3 as catalyst are due to a dynamic interconversion between two C2-symmetric enantiomeric structures via an open C2v-symmetric intermediate complex. Additionally, complexes 3−6 were found to be active in the polymerization of ε-caprolactone and rac-lactide. The activity of the zirconium dichloride complex 6 is higher than the activities of any of the titanium dialkoxide complexes 3−5 both in ε-caprolactone and in rac-lactide polymerizations.

Insertion Reactions at Cyclobutylene-Bridged ansa-Metallocene Complexes: A Quest for the Influence of Covering Phenylene Units

The cyclobutylene-bis(2-indenyl)zirconium dichloride complex (4), derived from an intramolecular photochemical [2+2] cycloaddition reaction of bis[2-(methylethenyl)indenyl]zirconium dichloride (3), was reacted with methyllithium or phenyllithium to yield the corresponding cyclobutylene-bis(2-indenyl)-zirconium dimethyl (12) or diphenyl (13) complex, respectively. Insertion of carbon monoxide into the Zr-phenyl linkage of 13 yielded the O-inside η 2 -benzoyl ansa-zirconocene complexes 18-syn/anti, which were characterized by X-ray diffraction. tert-Butyl isocyanide insertion into the Zr-CH 3 bond of 12 gave the N-inside η 2 -iminoacyl metallocene isomers 17-syn and 17-anti; the latter was characterized by X-ray diffraction. Under kinetic control tert-butyl isonitrile insertion into 12 gave the N-outside η 2 -iminoacyl metallocene isomers 25-syn/25-anti, which rearranged to 17-syn/anti at 243 K with Gibbs activation energies of ΔG ‡ rearr = 18.0/17.8 ± 0.3 kcal·mol -1 , respectively. The analogous rearrangement of the N-outside to N-inside isomers of the corresponding cyclobutylene-bis(cyclopentadienyl)Zr-(η 2 -iminoacyl) reference systems (23-syn/anti to 24-syn/anti) is much faster (203 K: ΔG ‡ rearr = 14.7/14.9 ± 0.3 kcal·mol -1 ). Similar differences in the kinetic N-outside to thermodynamic N-inside η 2 -iminobenzoyl metallocene isomerization were observed for the tert-butyl isonitrile insertion products of the cyclobutylene-bis(2-indenyl)ZrPh2 (13) and cyclobutylene-bis(C 5 H 4 )ZrPh 2 (15) systems, which indicates a pronounced influence of the covering phenylene groups on the σ-ligand chemistry in these rigid ansa-metallocene systems.

Stereoselective synthesis of an ansa-zirconocene in a spirane scaffold

Methodology is described for the preparation of a rigid C 2-bridged zirconocene catalyst system where the C 2-bridge is embedded in a spirane scaffold. The ligand was prepared from 3,4-dihydro-2 H-fluoren-1(9 H)-one. Initially, the oxo group was converted into a spirocyclobutanone function. Further conversion to a fulvene was followed by regio- and stereoselective saturation to provide the ligand cis-2-(cyclopentadienyl)-1′,2′,3′,4′-tetrahydro-9 H-spiro[cyclobutane-1,1′-fluorene]. The ligand was dilithiated and reacted with zirconium tetrachloride to provide the corresponding (η 5-cyclopentadienyl)-spiro[cyclobutane-1,1′-(η 5-fluorenyl)]zirconium dichloride complex. The structure of the zirconocene dichloride has been established by crystal X-ray analysis.

Zirconium Bisamidinate Complexes with Sterically Demanding Ligands: Structure, Solution Dynamics, and Reactivity

Bisamidinate zirconium dichloride and dimethyl complexes with the sterically demanding amidinate ligands [PhC(NAr)(2))](-) (A) and [PhC(NAr)(NAr')](-) (B) (Ar = 2,6-(Pr2C6H3)-Pr-i; Ar' = 2,6-Me2C6H3) were prepared. The steric demand of ligand A induces the unusual trans geometry in trans-(A)(2)ZrCl2, whereas (A)(2)ZrMe2 and (B)(2)ZrX2 (X = Cl, Me) adopt the more usual cis-X-2 geometry. The dynamic behavior of these complexes in solution was studied by 1D and 2D H-1 NMR spectroscopy. Reaction of (A)(2)ZrMe2 with H-2 leads, after stepwise hydrogenolysis of the Zr-Me bonds, to cyclometalation of the two amidinate ligands. The same product was obtained by thermolysis of the dimethyl complex. The square pyramidal five-coordinate 10 valence electron cationic monomethyl species [(A)(2)ZrMe](+) was generated and structurally characterized. Remarkably, the compound is unreactive toward ethylene, H-2, and CO. The sterically slightly less encumbered species [(B)(2)ZrMe](+) does polymerize ethylene, albeit with modest activity.

Synthesis and Structure of Group 4 Iminophosphonamide Complexes

The syntheses of a variety of iminophosphonamide (PN2) ligands (2a−f), the corresponding hydrochloride salts (1a−c), and a number of bis(PN2) dichloride complexes of group 4 (3a−e) and their corresponding dialkyls (5a−e) are described. A novel monosubstituted PN2 “ate” complex 4 was prepared from ligand 2f and Zr(NMe2)4 on treatment with excess Me2NH·HCl. Piano-stool PN2 zirconium dichloride complexes 6a−h were accessible on treatment of CpZr(NMe2)3 (Cp = C5H5, Cp*) with PN2 ligands 2a−e, followed by metathesis with excess Me3SiCl or Me2NH·HCl (6a−g) or at low T with ethereal HCl (6h). Dialkyl derivatives 8a−h could be prepared from 6a−h or directly from ligands 2 and CpMMe3 (Cp = C5H5, Cp*; M = Ti or Zr). The intermediate Cp(PN2)Zr(NMe2)2, precursor to 6h, rearranged to the novel terminal difluoride complexes 7a,b at room temperature. A variety of complexes 3 and 6 or their corresponding alkyl derivatives have been characterized by X-ray crystallography. In addition, the novel “ate” complex 4 and difluoride complexes 7a,b have been structurally characterized in this manner. The structures of 7a,b in the solid state reveal strong, intramolecular coordination of the NMe2 group to the metal center, resulting in eight-coordinate complexes. One of these complexes is fluxional in solution, suggesting rapid exchange of bound versus free NMe2 groups coupled with the formation of coordination stereoisomers.

Bis(amido)cyclodiphosph(III)azane]dichlorozirconium Complexes for Ethene Polymerization

AbstractA series of new zirconium dichloride complexes bearing bulky cis‐bis(amino)cyclodiphosph(III)azane ligands, [(RN)2(tBuNP)2]ZrCl2 [R = phenyl (7), diphenylmethyl (8), 2,6‐diethylphenyl (9), 2,5‐di‐tert‐butylphenyl (10), and 2,6‐diisopropylphenyl (11)] were prepared in high yields by a two‐step synthetic route. The structure of cis‐[(Ph2CHN)(tBuNP)]2Zr(NMe2)2 (8a), determined by X‐ray analysis, shows that the zirconium atom has a distorted trigonal‐bipyramidal configuration consisting of four equidistant metal−amido nitrogen bonds and an additional coordination between the metal and a nitrogen atom from the cyclodiphosph(III)azane ring. After methylaluminoxane activation, these complexes exhibit moderate to high activities in ethene polymerization and produce high molar mass polyethene (Mw up to 1100 kg/mol). Polymerization experiments reveal that the behavior of bis(amido)cyclodiphosph(III)azane‐based ZrIV catalysts depends on the nature and steric bulkiness of the amido substituents, reaction temperature, MAO/zirconium ratio, as well as monomer pressure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

11B NMR Analysis of Catalyst Solutions Obtained from Bis(boratabenzene)zirconium Dichloride Complexes and Methylaluminoxane

Boratabenzene complexes of the type [C5H5B-R]2ZrCl2 are activated by methylaluminoxane (MAO) to form catalyst mixtures that polymerize (R = dialkylamino) or oligomerize (R = alkyl, alkoxy) ethylene. The selectivity for specific olefin products is influenced by the exocyclic substituent on the boratabenzene ring. When [C5H5B-OEt]2ZrCl2(1)/MAO is exposed to 1 atm of ethylene, α-olefins are produced in greater than 99% purity, while [C5H5B-Me]2ZrCl2(4)/MAO/C2H4 gives a mixture of α-olefins, internal olefins, and vinylidenes. Other catalysts, such as [C5H5B-OCH2Ph]2ZrCl2(2)/MAO and [C5H5B-OCy]2ZrCl2(3)/MAO, oligomerize ethylene with selectivities for α-olefin production that are between those of 1/MAO and 4/MAO. The isomerization and dimerization of 1-decene by 1−4 with MAO agree well with the ethylene data. More selective catalysts (1/MAO) exhibit slow rates of isomerization, while less selective catalysts (4/MAO) rapidly convert 1-decene to 2-decene and 2-octyl-1-dodecene. The presence of boron in the ancillary ligands of these catalyst mixtures allows their reaction chemistry to be examined using 11B NMR spectroscopy. Signals are observed at 35 and 42 ppm for 1/MAO and 4/MAO, respectively. These signals remain unchanged over a 3 h period. For 2/MAO the initial resonance at 35 ppm diminishes with time and gives rise to a signal at 42 ppm. Two new zirconium complexes, [C5H5B-OMe]2ZrCl2(5)/MAO and [C5H5B-OCMe3]2ZrCl2(6)/MAO, were synthesized to further examine steric effects. With 5/MAO, no exchange was observed. A rapid exchange of exocyclic substituent occurs for 6/MAO. Ethylene oligomerization and 1-decene isomerization reactions with 5/MAO and 6/MAO support these observations. Different commercially available samples of MAO were also compared.

Synthesis and characterization of planarly chiral nonbridged bis(1- R-indenyl) zirconium dichloride complexes and X-ray structure of rac-[(η 5-C 9H 6-1-C(CH 3) 2 o-C 6H 4OCH 3) 2ZrCl 2]·THF

Reactions of the lithium salts of 3-substituted indenes 1, 2 with ZrCl 4(THF) 2 gave two series of nonbridged bis(1-substituted)indenyl zirconocene dichloride complexes. Fractional recrystallization from THF–petroleum ether furnished the pure racemic and mesomeric isomers of [(η 5-C 9H 6-1-C(R 1)(R 2) o-C 6H 4OCH 3) 2ZrCl 2]· nTHF (R 1=R 2=CH 3, n=1, rac- 1a and meso- 1b; R 1=CH 3, R 2=C 2H 5; n=0.5 or 0, rac- 2a and meso- 2b), respectively. Complex 1a was further characterized by X-ray diffraction to have a C 2 symmetrically racemic structure, where the six-member rings of the indenyl parts are oriented laterally and two o-CH 3OC 6H 4C(CH 3) 2 substituents are oriented to the open side of the metallocene (Ind: bis-lateral, anti; Substituent: bis-central, syn). The four zirconocene complexes are highly symmetrical in solution as characterized by room temperature 1H-NMR, however 1H– 1H NOESY of meso- 1b shows that some of the NOE interactions arise from the two separated indenyl parts of the same molecule, which can only be well explained by taking into account the torsion isomers in solution.

New diamide-diamine ligands and their zirconium and hafnium dichloride and bis(dimethylamide) complexes.

The multigram syntheses of the protio ligands (2-NC(5)H(4))CH(2)N(CH(2)CH(2)NHSiMe(2)R)(2) (R = Me, H(2)N(2)NN' 3; R = (t)Bu, H(2)N(2)NN() 4) are described via reactions of the previously reported (2-NC(5)H(4))CH(2)N(CH(2)CH(2)NH(2))(2) (1). A new synthesis of 1 is reported starting from 2-aminomethylpyridine and N-tosylaziridine, proceeding via (2-NC(5)H(4))CH(2)N(CH(2)CH(2)NHTs)(2) (2). Reaction of H(2)N(2)NN' or H(2)N(2)NN* with (n)BuLi gives good yields of the dilithiated derivatives Li(2)N(2)NN' and Li(2)N(2)NN*. Reaction of H(2)N(2)NN' or H(2)N(2)NN* with [MCl(2)(CH(2)SiMe(3))(2)(Et(2)O)(2)] gives the cis-dichloride complexes [MCl(2)(L)] (L = N(2)NN', M = Zr 7 or Hf 8; L = N(2)NN(), M = Zr 9). The corresponding reactions of H(2)N(2)NN' or H(2)N(2)NN* with [Zr(NMe(2))(4)] afford the bis(dimethylamide) derivatives [Zr(NMe(2))(2)(L)] (L = N(2)NN' 10 or N(2)NN* 11). All of these protonolysis reactions proceed smoothly and in good yields. Attempts to prepare the titanium complexes [Ti(X)(2)(N(2)NN')] (X = Cl or NMe(2)) were unsuccessful. The X-ray crystal structures of (2-NC(5)H(4))CH(2)N(CH(2)CH(2)NHTs)(2).EtOH, [ZrCl(2)(N(2)NN')].0.5C(6)H(6), [Zr(NMe(2))(2)(N(2)NN')], and [Zr(NMe(2))(2)(N(2)NN*)] are reported.

Effects of an Interannular Bridge on Spectral and Electronic Properties of Bis(cyclopentadienyl)- and Bis(indenyl)zirconium(IV) Complexes

Interconnection of the indenyl ligands of bis(indenyl)zirconium dichloride complexes by a 1,1‘-positioned Me2Si or (CH2)2 bridge causes pronounced bathochromic shifts of the longest wavelength UV/vis absorption bands by ca. 50 nm, while much smaller shifts are caused by a Me2Si bridge in otherwise analogous bis(cyclopentadienyl) complexes. Extended Hückel MO calculations show that overlap between the empty 4d orbitals of the ZrCl22+ fragment and the highest filled π orbitals of the indenyl anions is decreased when a Me2Si bridge forces the indenyl ligands into a lateral orientation. Consequences of this orbital mismatch, e.g. on electron densities at the Zr center, are discussed.

Synthesis, characterization, and catalytic properties of bis[alkylindenyl]-, bis[alkenylindenyl]- and [alkenylindenyl(cyclopentadienyl)]zirconium dichloride complexes

4,7-Dimethylindenyl lithium or 2,4,7-trimethylindenyl lithium reacts with 1-bromobutane, 1-chloro-2-propene, or 1-bromo-3-methyl-2-butene to give 3-butyl-4,7-dimethyl-1 H-indene ( 1), 3-(2-propene-1-yl)-2,4,7-trimethyl-1 H-indene ( 2), or 3-(3-methyl-2-butene-1-yl)-2,4,7-trimethyl-1 H-indene ( 3), respectively. Deprotonation of 1– 3 with n-butyl lithium yields the lithium salts 1a– 3a. The reactions of 1a– 3a and of [1-(4-pentene-1-yl)indenyl]lithium ( 4a) with zirconiumtetrachloride produce the complexes bis[1-butyl-4,7-dimethylindenyl]- ( 1b), bis[1-(2-propene-1-yl)-2,4,7-trimethyl-indenyl]- ( 2b), bis[1-(3-methyl-2-butene-1-yl)-2,4,7-trimethylindenyl]- ( 3b) or bis[1-(4-pentene-1-yl)indenyl]zirconium dichloride ( 4b). The reaction of cyclopentadienylzirconium trichloride with [2-(3-butene-1-yl)-4,7-dimethylindenyl]lithium or [2-(4-pentene-1-yl)-4,7-dimethylindenyl]lithium affords the mixed complexes [2-(3-butene-1-yl)-4,7-dimethylindenyl(cyclopentadienyl)]zirconium dichloride ( 5c) or [2-(4-pentene-1-yl)-4,7-dimethylindenyl(cyclopentadienyl)]zirconium dichloride ( 6c). All new compounds were characterized by elemental analysis, 1H- and 13C{ 1H}-NMR spectroscopy as well as by mass spectrometry. In addition, single-crystal X-ray structural analysis was done for 3b. The complexes 1b– 4b, 5c, and 6c were tested as catalysts for the homopolymerization and copolymerization of ethene and propene and the results were compared to those of analogous compounds.

Synthesis, Structural Investigation, and Reactivity of Neutral and Cationic Bis(guanidinato)zirconium(IV) Complexes

The mono(guanidinato) complex Cp(guan)ZrCl2 (1; guan = η2-(iPrN)2C(NMe2)) was prepared by treatment of CpZrCl3 (Cp = η5-C5H5) with the in situ generated lithium guanidinate salt 2. The dimethylamino group of 1 resists quaternization by alkylating and silylating reagents. Complex 1 undergoes ligand redistribution when treated with 2 equiv of MeLi, but reaction with 2 equiv of MeMgCl affords the dimethyl derivative Cp(guan)ZrMe2 (3). Insertion of 2 equiv of diisopropylcarbodiimide into the Zr−N bonds of (Me2N)2ZrCl2(THF)2 produces the bis(guanidinato)zirconium dichloride complex (guan)2ZrCl2 (4). Alkylation of 4 with 2 equiv of MeLi or PhCH2MgCl affords the dialkyl derivatives (guan)2ZrMe2 (5) and (guan)2Zr(CH2Ph)2 (6), respectively. Variable-temperature NMR experiments on 6 reveal a limiting C2-symmetric solution structure at 253 K. Complex 5 undergoes reaction with electrophiles (Me3SiOTf (OTf = OSO2CF3), B(C6F5)3, [Ph3C][B(C6F5)4]) to yield stable products of methide abstraction: neutral complexes (guan...

Synthesis, structure and ethylene polymerization behavior of zirconium complexes with chelating ketoiminate ligands

Mixed ketoiminate/ketoimine/pentamethylcyclopentadienyl (Cp*) complex of zirconium, [(η 5-Cp*){CH 3C(O)CHC(NHR)CH 3}{CH 3C(O)CHC(NR)CH 3}ZrCl 2] (R=4 -CF 3Ph) ( 3) has been prepared in high yield by the reaction of one equivalent of 4-CF 3-phenyl-β-ketoimine ( 1a) and one equivalent of lithium 4-CF 3-phenyl-β-ketoiminate ( 2a) with one equivalent of Cp*ZrCl 3 in Et 2O. Bis(ketoiminate)zirconium dichloride complexes, 4 and 6, have been also prepared in high yield by the reaction of amine elimination of ketoimine ligands, respectively 1a and 1b, with Zr(NMe 2) 4 and followed by chlorination reaction with TMSCl. The X-ray crystallography reveals that the compound 3 is based on distorted octahedral geometry containing a ketoimine and a ketoiminate. The ketoiminate ligand coordinates to the zirconium as a bidentate ligand, leaving the metal center coordinatively unsaturated and thus leading to an additional binding of a ketoimine ligand to the metal to stabilize the complex 3. The zirconium complexes 3, 4 and 6 provide the moderate activity for the polymerization of ethylene in the presence of MMAO cocatalyst. Low molecular weight and high density polyethylene was obtained.