Gas-surface reactions between pentakis(dimethylamido)tantalum and surface grown hyperbranched polyglycidol films

We have investigated the growth of hyperbranched polyglycidol films, and their subsequent reaction with a transition metal coordination complex, pentakis(dimethylamido)tantalum, Ta[N(CH 3) 2] 5 using ellipsometry, contact angle measurements, atomic force microscopy and X-ray photoelectron spectroscopy (XPS). Up to thicknesses of approximately 150 A, the growth of polyglycidol is approximately linear with reaction time for growth activated using either sodium methoxide or an organic superbase. The reaction of Ta[N(CH 3) 2] 5 at room temperature with these layers depends strongly on their thickness--the amount of uptake of Ta by the surface increases with the thickness of the organic layer, and thicker films also lead to more extensive ligand exchange reactions (with the R-OH groups), with as many as 4 ligands being lost on the thicker organic films. Ta penetrates the surface of all films examined (thicknesses 30-84 A), but the average depth of the penetration is nearly independent of the thickness of the organic film, and it is approximately 15-25 A. Modification of the polyglycidol with an aminoalkoxysilane introduces a significant fraction of -NH 2 termination in the organic layer. Reactions of this layer with the Ta complex are quite different than those on an unmodified layer--now on average only a single ligand exchange reaction occurs, while on the unmodified surface as many as four ligands are exchanged.     

Hybrid perovskite resulting from the solid-state reaction between the organic cations and perovskite layers of alpha1-(Br-(CH(2))(2)-NH(3))(2)PbI(4)

The alpha1-(Br-(CH(2))(2)-NH(3))(2)PbI(4) hybrid perovskite undergoes a solid-state transformation, that is, the reaction between the organic cations and the perovskite layers to give the new hybrid perovskite (Br-(CH(2))(2)-NH(3))(2-x)(I-(CH(2))(2)-NH(3))(x)PbBr(x)I(4-x), based on mixed halide inorganic layers. This transformation has been followed by a conventional powder X-ray diffraction system equipped with a super speed detector, and both solid-state (13)C NMR and ESI/MS measurements have been adopted in the estimation of the rate of halide substitution. The first reaction step leads to the special composition of x approximately 1 (A phase), while the complete substitution is not achieved even at elevated temperature (x(max) approximately 1.85 (B phase)). This unprecedented solid-state reaction between organic and inorganic components of a hybrid perovskite can be considered as a completely new strategy to achieve interesting hybrid perovskites.     

Hydroxyl-terminated dendritic oligomers from bile acids: synthesis and properties

[reaction: see text] The high reactivity of the chloroacetyl group has been exploited for the synthesis of bile acid based first and second generation dendrons with multiple hydroxyl groups. The synthesis involves only a few steps and avoids the use of protecting groups for the terminal hydroxyl groups. These dendritic structures with facially amphiphilic bile acid backbones on the periphery were able to solubilize cresol red, a hydrophilic dye, in a nonpolar solvent. HPLC analysis of the dendrons suggests that hydrophobicity increases with increase in oligomer size, but in each generation, the dendrons with a higher degree of branching are less hydrophobic.     

A Hyperbranched Poly(ethyleneimine) Grown on Surfaces

Aminosilylated substrate was treated with aziridines in order to prepare hyperbranched polymers on solid supports such as silicon wafer and fused silica. It is observed that the primary amine on the substrate is good enough to initiate the ring-opening polymerization of aziridine. Measuring the thickness of the film and the absolute density of the primary amine functionality shows that a very highly branched poly(ethyleneimine) is formed upon the reaction. The surface density of the primary amine functional group (-NH(2)) on the very top surface increased dramatically (from 3.5 amines/nm(2) to 66 amines/nm(2)). A protected aziridine, benzyl 1-aziridinecarboxylate, was employed for the stepwise growth of the film. Two step-processes, chain growth and deprotection, were successful in growing the molecular layer, and a linear chain was formed without branching. Copyright 2000 Academic Press.     

Convergent synthesis of internally branched PAMAM dendrimers

[reaction: see text] A series of aliphatic internally branched poly(amido amine) dendrons and dendrimers has been synthesized. The internal branching unit was 1,2-propanediamine and a series of PAMAM-type dendrons of the types AB2, AB4, and AB8 were built. These were anchored on a core molecule containing four carboxylic acid moieties and the 1,2-propanediamine unit resulted in PAMAM dendrimers with 4, 8, 16, and 32 end groups.     

Synthesis of Polyisoprene Terpenoid Dendrons and their Applications in Oligo(phenylene ethynylene)s as “Shells”

The novel double‐stage convergent synthesis of a new class of polyisoprene terpenoid (PIPTP) dendrons is described. PIPTP dendrons bear a highly branched aliphatic hydrocarbon skeleton and a hydrophilic hydroxy focal point functionality. These dendrons have the specific formula C_(5×2^G+1_‐5)H_(5×2^G+2_‐8)O, and each dendritic layer is constructed from an isoprene unit. The key branching steps involve a double alkyl‐metal addition to an ester functionality, followed by deoxygenation of the resulting tertiary alcohol by triethylsilane and trifluoroacetic acid, then hydrogenation or hydrogenolysis. The dendrons were also attached to oligo(phenylene ethynylene)s (OPEs) so as to function as protective shells to allow fine tuning of the nanoscopic environment around the OPE moiety, and to exert precise control of the packing density and intermolecular interaction between the OPE cores. Fluorescence quantum yield data reveal that the OPE core is better encapsulated by the PIPTP dendrons than by Fréchet dendrons.     

A theoretical investigation of the production of branched copolymers in continuous stirred tank reactors

A comprehensive mathematical model for free-radical copolymerization reactions has been developed for a homogeneous continuous stirred tank reactor. The present model is based on a fairly general copolymerization scheme accounting for the formation of linear and branched copolymer chains. Both chain transfer to polymer and terminal double bond reactions are considered in order to predict the long chain branching frequency. Changes in molecular weight, composition and degree of branching occurring during the copolymerization reaction are modelled using the method of moments. To break-down the dependence of the moment equations on higher order moments two different closure methods are considered. The predictive capabilities of the model are examined in relation to the solution copolymerization of methyl methacrylate with vinyl acetate. It is shown that both chain transfer to polymer and terminal double bond reactions significantly contribute to the broadening of the molecular weight and degree of branching distributions. Furthermore, the terminal double bond reaction effects significantly the copolymer number-average molecular weight and the concentration of terminal double bonds.     

A supersonic molecular beam study of the reaction of tetrakis(dimethylamido)titanium with self-assembled alkyltrichlorosilane monolayers

The reaction of a transition metal coordination complex, Ti[N(CH(3))(2)](4), with self-assembled monolayers (SAMs) possessing-OH, -NH(2), and -CH(3) terminations has been examined using supersonic molecular beam techniques. The emphasis here is on how the reaction probability varies with incident kinetic energy (E(i)=0.4-2.07 eV) and angle of incidence (theta(i)=0 degrees -60 degrees ). The most reactive surface is the substrate underlying the SAMs-SiO(2) with a high density of -OH(a) (>5 x 10(14) cm(-2)), "chemical oxide." On chemical oxide, the dynamics of adsorption are well described by trapping, precursor-mediated adsorption, and the initial probability of adsorption depends only weakly on E(i) and theta(i). The dependence of the reaction probability on substrate temperature is well described by a model involving an intrinsic precursor state, where the barrier for dissociation is approximately 0.2-0.5 eV below the vacuum level. Reaction with the SAMs is more complicated. On the SAM with the unreactive, -CH(3), termination, reactivity decreases continuously with increasing E(i) while increasing with increasing theta(i). The data are best interpreted by a model where the Ti[N(CH(3))(2)](4) must first be trapped on the surface, followed by diffusion through the SAM and reaction at the SAMSiO(2) interface with residual -OH(a). This process is not activated by E(i) and most likely occurs in defective areas of the SAM. On the SAMs with reactive end groups, the situation is quite different. On both the-OH and -NH(2) SAMs, the reaction with the Ti[N(CH(3))(2)](4) as a function of E(i) passes through a minimum near E(i) approximately 1.0 eV. Two explanations for this intriguing finding are made-one involves the participation of a direct dissociation channel at sufficiently high E(i). A second explanation involves a new mechanism for trapping, which could be termed penetration facilitated trapping, where the Ti[N(CH(3))(2)](4) penetrates the near surface layers, a process that is activated as the molecules in the SAM must be displaced from their equilibrium positions.     

Supramolecular Self-Associations of Amphiphilic Dendrons and Their Properties

This review presents precisely defined amphiphilic dendrons, their self-association properties, and their different uses. Dendrons, also named dendritic wedges, are composed of a core having two different types of functions, of which one type is used for growing or grafting branched arms, generally multiplied by 2 at each layer by using 1→2 branching motifs. A large diversity of structures has been already synthesized. In practically all cases, their synthesis is based on the synthesis of known dendrimers, such as poly(aryl ether), poly(amidoamine) (in particular PAMAM), poly(amide) (in particular poly(L-lysine)), 1→3 branching motifs (instead of 1→2), poly(alkyl ether) (poly(glycerol) and poly(ethylene glycol)), poly(ester), and those containing main group elements (poly(carbosilane) and poly(phosphorhydrazone)). In most cases, the hydrophilic functions are on the surface of the dendrons, whereas one or two hydrophobic tails are linked to the core. Depending on the structure of the dendrons, and on the experimental conditions used, the amphiphilic dendrons can self-associate at the air-water interface, or form micelles (eventually tubular, but most generally spherical), or form vesicles. These associated dendrons are suitable for the encapsulation of low-molecular or macromolecular bioactive entities to be delivered in cells. This review is organized depending on the nature of the internal structure of the amphiphilic dendrons (aryl ether, amidoamine, amide, quaternary carbon atom, alkyl ether, ester, main group element). The properties issued from their self-associations are described all along the review.     

The reaction of tetrakis(dimethylamido)titanium with self-assembled alkyltrichlorosilane monolayers possessing -OH, -NH2, and -CH3 terminal groups

The reactions of tetrakis(dimethylamido)titanium, Ti[N(CH(3))(2)](4), with alkyltrichlorosilane self-assembled monolayers (SAMs) terminated by -OH, -NH(2), and -CH(3) groups have been investigated with X-ray photoelectron spectroscopy (XPS). For comparison, a chemically oxidized Si surface, which serves as the starting point for formation of the SAMs, has also been investigated. In this work, we examined the kinetics of adsorption, the spatial extent, and stoichiometry of the reaction. Chemically oxidized Si has been found to be the most reactive surface examined here, followed by the -OH, -NH(2), and -CH(3) terminated SAMs, in that order. On all surfaces, the reaction of Ti[N(CH(3))(2)](4) was relatively facile, as evidenced by a rather weak dependence of the initial reaction probability on substrate temperature (T(s) = -50 to 110 degrees C), and adsorption could be described by first-order Langmuirian kinetics. The use of angle-resolved XPS demonstrated clearly that the anomalous reactivity of the -CH(3) terminated SAM could be attributed to reaction of Ti[N(CH(3))(2)](4) at the SAM/SiO(2) interface. Reaction on the -NH(2) terminated SAM proved to be the "cleanest", where essentially all of the reactivity could be associated with the terminal amine group. In this case, we found that approximately one Ti[N(CH(3))(2)](4) adsorbed per two SAM molecules. On all surfaces, there was significant loss of the N(CH(3))(2) ligand, particularly at high substrate temperatures, T(s) = 110 degrees C. These results show for the first time that it is possible to attach a transition metal coordination complex from the vapor phase to a surface with an appropriately functionalized self-assembled monolayer.     

Investigation of the association and flexibility of cationic lipidic peptide dendrons by NMR spectroscopy

The cationic peptide dendrons synthesized and studied are lower generation polylysine-based partial dendrimers with or without lipid chains in the core. The dendrons with lipidic chains can be utilized as protein and liposomal mimics because of their unique structural properties. The full assignments of three different dendrons (L)7(NH2)8, (C14)1(L)7(NH2)8 and (C14)3(L)7(NH2)8 were obtained in D2O and H2O/D2O using a 500 MHz NMR spectrometer. The hydrophobic lipidic core of branched polylysine dendrons was found to induce aggregation upon increasing concentration. Because non-lipidic dendrons do not self-assemble, the behaviour and internal structural features of two different dendrons with one and three C14 hydrocarbon chains were explored. The critical association concentration clearly depends on the number of core hydrophobic residues and the association starts at 0.025 mM for (C14)1(L)7(NH2)8 and 0.05 mM for (C14)3(L(7(NH2)8. Chemical shift analysis also revealed that the hydrophobic chains of the dendrons associate in the core, whereas the polar head groups (NH2) are mainly located at the surfaces of the aggregates. The T1 relaxation time measurements showed that the mobility of the hydrocarbon chain is greater with the monomeric form of dendron (C14)1(L)7(NH2)8) than that of monomer (C14)3(L)7(NH2)8. The inter-chain hydrophobic interactions restrict the flexibility of the dendron with three hydrocarbon chains. As expected, the flexibility of the monomeric form is higher than that of the aggregated state for both of the dendrons.     

Dendritic receptors designed to bind polyanions in both organic and aqueous media

This paper reports the synthesis of dendrons containing a spermine unit at their focal point. The dendritic branching is based on l-lysine building blocks, and has terminal oligo(ethyleneglycol) units on the surface. As a consequence of the solubilising surface groups, these dendrons have high solubility in solvents with widely different polarities (e.g., dichloromethane and water). The protonated spermine unit at the focal point is an effective anion binding fragment and, as such, these dendrons are able to bind to polyanions. This paper demonstrates that polyanions can be bound in both dichloromethane (using a dye solubilisation assay) and in water (competitive ATP binding assay). In organic media the dendritic branching appears to have a pro-active effect on the solubilisation of the dye, with more dye being solubilised by higher generations of dendron. On the other hand, in water the degree of branching has no impact on the anion binding process. We propose that in this case, the spermine unit is effectively solvated by the bulk solvent and the dendritic branching does not need to play an active role in assisting solubility. Dendritic effects on anion binding have therefore been elucidated in different solvents. The dendritic branching plays a pro-active role in providing the anion binding unit with good solubility in apolar solvent media.     

Hybrid organic-inorganic nanomaterials based on polythiophene dendronized nanoparticles

In this work, the synthesis, characterization, and applications of branched oligothiophene dendrons that act as electroactive surfactants for the capping of Au metal nanoparticles and CdSe quantum dots are described. Two distinct methods have been employed for synthesis: a ligand exchange process and a direct-capping synthesis approach. The coverage of the dendrons per nanocrystal, the nature of the surface coordination interactions, and energy transfer interactions were studied in detail using UV-vis absorbance, FT-IR, AFM, TEM, and photoluminescence spectroscopy. The competition/displacement in ligand metathesis is highlighted by the size of the dendron and nature of binding on semiconductor nanocrystals. In the other system using the direct capping method, the size of the Au nanoparticle is mediated by the dimensions of the ligand, i.e. alkyl chain spacer and dendron branching or size. These hybrid dendron/nanoparticle complexes are generally very soluble and stable in non-polar solvents. They exhibit energy transfer, surface plasmon resonance effects, and photoinduced charge transfer interactions between the metal/semiconductor and conjugated ligands. Adsorption on mica and graphite surfaces was observed. A one-layer photovoltaic cell was fabricated to demonstrate the potential for device applications.     

Coupling vs surface-etching reactions of alkyl halides on GaAs(100). 2. CH2I2 reactions

Surface reactions of CH2I2 on gallium-rich GaAs(100)-(4 x 1), studied by temperature programmed desorption and X-ray photoelectron spectroscopy (XPS), show CH2I2 adsorbs dissociatively at liquid nitrogen temperatures to form surface chemisorbed CH2(ads) and I(ads) species. Controlled hydrogenation of a fraction of the CH2(ads) species in the chemisorbed layer by the background hydrogen radicals results in a surface layer comprising both CH3(ads) and CH2(ads) species. This hydrogenation step initiates a plethora of further surface reactions involving these two species and I(ads). Thermal activation leads to three sequential methylene insertions (CH2(ads)) into the CH3-surface bond to form three higher alkyl (ethyl (C2), propyl (C3), and butyl (C4)) species, which undergo beta-hydride elimination to evolve the respective higher alkene (ethene, propene, and butene). In competition with beta-hydride elimination, reductive elimination of the ethyl and propyl species with I(ads) occurs to liberate the respective alkyl iodide. Beta-hydride elimination in the alkyls, in the temperature range 420-520 K, is the more dominant pathway, and it is also the rate-limiting step for further chain propagation. The evolution of the alkyl iodides represents the only pathway for the removal of surface iodines in this study and is different from previous investigations where gallium and arsenic iodide etch products (GaI(x), AsI(x) (x = 1-3)) formed instead. The desorption of methane and methyl iodide, formed from surface CH3(ads) species at high temperatures by the reaction between surface methylenes and hydrogens eliminated from the surface C2-C4 alkyls, terminates the chain propagation. We discuss the reaction mechanisms by which the observed reaction products form and postulate reasons for the reaction pathways adopted by the surface species.     

SYNTHESIS OF BRANCHED POLYETHYLENE USING (α-DIIMINE)NICKEL(Ⅱ)TiCl4 COMBINED AND SUPPORTED CATALYST*

(α-Diimine)nickel(Ⅱ) {[C6H5 -N = C(CH3)-C(CH3) = N -C6H5]NiBr2}-TiCl4 abbreviated as NiL-TiCl4 combined catalyst which is supported on MgCl2-SiO2 carrier has been prepared, by using alkyl aluminum (AIR3) as the cocatalyst in place of methylaluminoxane (MAO) to catalyze ethylene oligomerization and copolymerization in situ. The influences of procedure for supporting NiL-TiCI4, the molar ratio of NiL to TiCI4, cocatalyst type and polymerization temperature on the catalytic performance were studied. The degree of branching and the composition of the branched chain of polymers produced have been investigated by IR and ^13C-NMR spectra. The results show that the combined catalyst can synthesize the branched polyethylene with various banched chains .The polymerization reaction was monitored by gas chromatography and mass spectrometry (GC-MS). The results show that this catalyst promotes the oligomerization and copolymerization in situ for ethylene.     

Optical switching and antenna effect of dendrimers with an anthracene core

Dendrimers 6G(i) (i=1-4) consisting of an anthracene core and Fréchet dendrons which are attached via a CH(2)OCH(2) chain in the 9-position undergo quantitative and completely reversible intramolecular [4pi+4pi] cycloaddition. The process can be monitored by absorption and fluorescence measurements. The Fréchet dendrons act as an energy funnel that collects and focuses the photon energy but does not change the photostationary states, which for both directions are completely on the product side when the separate chromophores are selectively irradiated. The quantum yields of anthracene fluorescence and of singlet energy transfer from the dendrons to the core were studied as a function of dendrimer generation.     

The unexpected desulfurization of 4-aminothiophenols

Thermolysis of 4-aminophenyl benzyl sulfide at 523 K in the hydrogen donor solvent (HDS), 9,10-dihydroanthracene (AnH2), gave 4-aminothiophenol and toluene as the predominant products of the homolytic S-C bond cleavage. Under these conditions, a portion of the 4-aminothiophenol was desulfurized to aniline with first-order kinetics and with a rate constant estimated by kinetic modeling to be 7.0x10(-6) s-1. Starting with 4-NH2C6H4SH at 523 K, it was found that sulfur loss was more efficient in the non-HDSs, anthracene and hexadecane, than in AnH2. Under similar (competitive) reaction conditions, YC6H4SHs with Y=H, 4-CN, and 3-CF3 were completely inert; with Y=4-CH3O, there was some very minor desulfurization, whereas with Y=4-N(CH3)2 and 4-N(CH3)(H), the sulfur extrusions were as fast as that for Y=4-NH2. We tentatively suggest that this apparently novel reaction is a chain process initiated by the bimolecular formation of diatomic sulfur, S2, followed by a reversible addition of ground state, triplet 3S2 to the thiol sulfur atom, 4-NH2C6H4S upward arrow(SS upward arrow)H, and insertion into the S-H bond, 4-NH2C6H4SSSH. In a cascade of reactions, aniline and S8 are formed with the chains being terminated by reaction of 4-NH2C6H4S upward arrow(SS upward arrow)H with 4-NH2C6H4SH. Such a reaction mechanism is consistent with the first-order kinetics. That this reaction is primarily observed with 4-YC6H4SH having Y=N(CH3)2, N(CH3)(H), and NH2 is attributed to the fact that these compounds can exist as zwitterions.     

Janus-type dendrimer-like poly(ethylene oxide)s

A straightforward and original methodology allowing the synthesis of Janus-type dendrimer-like poly(ethylene oxide)s (PEOs) carrying orthogonal functional groups on their surface is described. The use of 3-allyloxy-1,2-propanediol (1) as a latent AB2-type heterofunctional initiator of anionic ring-opening polymerization (AROP) of ethylene oxide (EO) and of selective branching agents of PEO chain ends served to construct the two dendrons of these dendrimer-like PEOs, following a divergent pathway. Thus, the first PEO generation of the first dendron was grown by AROP from 1 followed by the reaction of the corresponding alpha-allyl,omega,omega'-bishydroxy- heterofunctional PEO derivative with 2-(3'-chloromethybenzyloxymethyl)-2-methyl-5,5-dimethyl-1,3-dioxane (2) used as a branching agent. This afforded the dendron A with four latent peripheral hydroxyls protected in the form of two ketal rings. The remaining alpha-allylic double bond of the PEO thus prepared was transformed into two hydroxyl groups using OsO4 in order to create the first PEO generation of the dendron B by AROP of EO. Allyl chloride (3) was then used as another (latent) branching agent to react with the terminal hydroxyl of the corresponding PEO chains. Deprotection under acidic conditions of the ketal groups of dendron A, followed by AROP of EO, afforded the second PEO generation on this face. This alternate and divergent procedure, combining AROP of EO and selective branching of PEO branches, could be readily iterated, one dendron after the other up to the generation six, leading to a Janus-type dendrimer-like PEO exhibiting a total mass of around 300 kg/mol and possessing 64 peripheral groups on each face. The possibility of orthogonal functionalization of the surfaces of such Janus-type dendritic PEOs was exploited. Indeed, a dendron of generation 4 was functionalized with hydroxyl functions at its periphery, whereas the other was end-capped with either tertiary amino or disulfide groups. In a variant of this strategy, azido groups and acetylene could also be orthogonally introduced at the periphery of the fourth generation Janus-type dendrimer-like PEO and subjected to polycondensation by a 1,3-dipolar cycloaddition reaction. This afforded a necklace-like covalent assembly of dendrimer-like PEOs through the formation of stable [1,2,3]-triazole linkages.     

Designer dendrimers: branched oligosulfonimides with controllable molecular architectures

The synthesis of "designer" dendrimers and dendrons with sulfonimide units at every branching point is reported. The synthesis is based on a series of (regio)selective functionalization reactions of amines and sulfonamides allowing precise control of the dendrimers' shape, the number of branches in each generation, and their peripheral decoration with functional groups. In principle, structurally different branches can be incorporated at any position within the dendrimer structure at will. Structurally perfect symmetrical and two-faced "Janus"-type dendrimers, as well as dendrimers and dendrons with intended interstices were synthesized on a preparative scale and fully characterized. Oligosulfonimide dendrons of various generations bearing an aryl bromide functional group at their focal points were attached to a p-phenylene core with the aid of Suzuki cross-coupling reactions resulting in dendrimers with photoactive terphenyl cores. The structure and the high purity of all dendritic sulfonimides were confirmed by means of (1)H and (13)C NMR, electrospray ionization mass spectrometry (ESI-MS), and elemental analysis. The utility of MALDI-TOF mass spectrometry for the analytical characterization of these dendrimers was evaluated in comparison to electrospray ionization. Two model branched oligosulfonimides were characterized in the solid state by single-crystal X-ray analysis. Reaction selectivities and conformation of sulfonimide branching points were rationalized by DFT calculations.     

SYNTHESIS OF BRANCHED POLYETHYLENE USING (α-DIIMINE)NICKEL(Ⅱ) -TiCl4 COMBINED AND SUPPORTED CATALYST

(a-Diimine)nickel(Ⅱ) {[C6H5 - N = C(CH3) - C(CH3) = N - C6H5]NiBr2}-TiCl4 abbreviated as NiL-TiCl4combined catalyst which is supported on MgCl2-SiO2 carrier has been prepared, by using alkyl aluminum (AlR3) as the cocatalyst in place of methylaluminoxane (MAO) to catalyze ethylene oligomerization and copolymerization in situ. The influences of procedure for supporting NiL-TiCl4, the molar ratio of NiL to TiCl4, cocatalyst type and polymerization temperature on the catalytic performance were studied. The degree of branching and the composition of the branched chain of polymers produced have been investigated by IR and 13C-NMR spectra. The results show that the combined catalyst can synthesize the branched polyethylene with various banched chains .The polymerization reaction was monitored by gas chromatography and mass spectrometry (GC-MS). The results show that this catalyst promotes the oligomerization and copolymerization in situ for ethylene.