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1.
Catalytic behavior of tetrahydroborate complexes of rare earth metals, Ln(BH4)3(THF)x (1: Ln = La, x = 3; 2: Ln = Pr, x = 2; 3: Ln = Nd, x = 3; 4: Ln = Sm, x = 3; 5: Ln = Y, x = 2.5; 6: Ln = Yb, x = 3), for ring-opening polymerization (ROP) of six-membered cyclic esters, δ-valerolactone (VL) and d,l-lactide (d,l-LA), was studied. The controlled polymerization of VL with 1-6 proceeded in THF at 60 °C. The catalytic activities of these complexes for the ROP of VL were observed to be in order of the ionic radii of the metals: 1(La) ≥ 2(Pr) ≥ 3(Nd) > 4(Sm) > 5(Y) > 6(Yb). The obtained polymers were demonstrated to be hydroxy-telechelic by 1H NMR and MALDI-TOF MS spectroscopy. The controlled ROP of d,l-LA also proceeded by these complexes. The activities of these complexes for the d,l-LA ROP were also in order of the ionic radii of the metals. 相似文献
2.
Nickel catecholate complexes, bis(diphenylphosphino)ethanenickelcatecholate [(dppe)NiO2C6H34-R1] R1 = CH3 (1), C(CH3)3 (2), H (3) and F (4)] were studied using CV and SWV techniques between −1.5 and +1.5 V at 50 mV s−1 in cathodic and anodic sweeps. Glassy carbon electrode was used with 0.1 M tetrabutylammonium tetrafluroborate (TBATFB) in CH2Cl2. Complexes 1-4 before addition of SO2, showed approximately reversible behaviour (ipa/ipc ≈ 1 and ΔE ≈ 77-88 mV); oxidation peaks observed between +313 and +524 mV, reduction peaks between +225 and +436 mV, depending on the substituent on the ligand. Detection limit 0.01 ppm, linear range 0.01-20 ppm, sensitivity 0.02 ppm/mV (with SWV) were obtained. The complexes 1 and 2 could be used as voltammetric sensors while complexes 3 and 4 would be suitable as amperometric sensors, for monitoring industrial SO2 emissions. 相似文献
3.
We report in this article the synthesis and characterization of a range of hyperbranched polyethylenes having various low and medium molecular weights by chain walking ethylene polymerization with Pd-diimine catalysts of reduced ligand steric crowdedness, which are intended for potential applications as novel synthetic base stocks. Four Pd-diimine catalysts featured with different ligand crowdedness, ([(RC6H3NC(R′)-C(R′)NC6H3R)Pd(CH3) (NCMe)]SbF6) (1, R = 2,6-(iPr)2, R′ = CH3; 2, R = CH3, R′ = H; 3, R = 2,6-(iPr)2, R′ = H; 4, R = CH3, R′ = CH3), were employed herein for ethylene polymerizations at different conditions. Generally, reducing ligand steric crowdedness (in the order 1 > 4 > 3 > 2) leads to decreased catalyst activity and dramatically reduced polymer molecular weight. As opposed to high-molecular-weight polymers (weight-average molecular weight (Mw): about 150 kg/mol) obtained with catalyst 1, low-molecular-weight polymers (Mw: below 1.0 kg/mol) were obtained with 2 and 3, and medium-molecular-weight polymers (Mw: about 25 kg/mol) were produced with 4. Despite their various reduced molecular weights, the polymers are all featured with highly branched chain structures with a total branching density of above 100 branches per 1000 carbons. The low- and medium-molecular-weight hyperbranched polymers synthesized with 2-4 display good potential for applications as synthetic base stocks. In comparison with three commercial poly(α-olefin) based synthetic base stocks, they exhibit similar thermal and viscosity properties. Meanwhile, it is also discovered that a subsequent one-pot hydrogenation step can be incorporated in the process after the Pd-diimine catalyzed polymerization step to render nearly fully saturated hyperbranched polymers without the use of additional hydrogenation catalysts. 相似文献
4.
Pd(II) complexes with the tridentate ligands heptadecafluorodecyl-thiophene-2-carboxylate (L1 = SOSRf1, Rf1 = (CH2)2(CF2)7CF3) and heptadecafluorononil thiophene-2-carboxylate (L2 = SOORf2, Rf2 = (CH2)(CF2)7CF3) have been synthesized, and their catalytic activities for the homogeneous hydrogenation of olefins have been studied with molecular hydrogen in scCO2 and organic solvents. Both perfluoroalkylated-heterocycle ligands potentially have three donor atom sets (SOO/SOS). Depending on the soft-hard interaction between palladium and the donor atoms of the ligands, different activities for the Pd(II) complexes were observed. The nature of the solvent had an effect upon the hydrogenation of olefins. The effects of temperature and H2 pressure on the hydrogenation of styrene were also investigated. 相似文献
5.
João Carlos Ramos 《Polymer》2006,47(24):8095-8100
(R)-(−) (1) and (S)-(+)-2-(3′-Thienyl)ethyl N-(3″,5″-dinitrobenzoyl)-α-phenylglycinate (2) monomers were synthesized, characterized, and polymerized in chloroform using FeCl3 as an oxidizing agent. Molecular weights of 2.6 × 104 and 3.2 × 104 for poly1 and poly2, respectively, were determined by SEC analysis. FTIR spectra of the polymers indicated the coupling of monomers through the α positions. UV-vis spectra showed absorption bands at λmax = 226 and 423 nm for poly1 and poly2, ascribed to transitions of side groups and polythiophene backbone, respectively. Poly1 and poly2 remained stable up to 210 °C. At higher temperatures, a two step weight loss degradation process was observed for both polymers by TGA analysis. 1H NMR, in the presence of Eu(tfc)3, and optical rotation measurements indicate the chiral properties of the monomers 1 ([α]D28 = −76.2) and 2 ([α]D28 = +76.0), and the maintenance of chirality after polymerization (poly1 [α]D28 = −29.0 and poly2 [α]D28 = +28.4, c = 2.5 in THF). According to scanning electron microscopic analysis, the polymers are highly porous. 相似文献
6.
De-Qing Shi 《Electrochimica acta》2007,53(4):1824-1829
The electrochemical properties of a series of cyclic arylboronic esters, XC6H4B(OR)2 [RR = CH2CH2; X = H (1a); p-Me (1b); p-OMe (1c); p-Cl (1d); p-Ph (1e); m-Cl (1f); m-OMe (1g); CF3 (1h); OMe (1i); 2,6-dimethyl (1j); 1b with RR = (CH2)3, (1k); 1b with RR = CMe2CMe2, (1m)] has been studied in acetonitrile by cyclic voltammetry (CV) and controlled-potential electrolysis (CPE). The CV of representative examples of aryl borates with different substituents show one irreversible oxidation wave on a Pt cathode, at 1.8-1.9 V (vs. Ag/AgCl), with a negligible substituent effect. The cathodic CPE process led to small amounts of biaryls only, whereas the direct anodic CPE could not be carried out practically due to low currents. However, in the presence of electrogenerated bromonium (or iodonium) ions a C-B bond cleavage does take place to yield the corresponding bromoaryls, brominated phenols, and arylboronic acids as the major products. 相似文献
7.
Toru Katsumata 《Polymer》2008,49(12):2808-2816
The polymerization of diphenylacetylene derivatives possessing tert-amine moieties, such as triphenylamine, N-substituted carbazole and indole, was examined in the presence of TaCl5-n-Bu4Sn (1:2) catalyst. A polymer with high molecular weight (Mw = 570 × 103) was obtained in good yield by the polymerization of diphenylamine-containing monomer 1b, whereas the isopropylphenylamine derivative (1c) gave a polymer with relatively low molecular weight (Mw = 2.4 × 103). The polymerization of monomer 1d containing cyclohexylphenylamine group did not proceed; however, carbazolyl- and indolyl-containing monomers also produced polymers. Poly(1b), poly(2f) and poly(4b) could be fabricated into free-standing membranes by casting toluene solutions of these polymers. The gas permeability of poly(1b) was too low to be evaluated accurately whereas poly(4b) possessing two chlorine atoms in the repeating unit showed higher gas permeability than that of poly(1b); furthermore, poly(2f) having trimethylsilyl and 3-methylindolyl groups exhibited relatively high gas permeability (). In the cyclic voltammograms of diphenylamino group-containing polymers, poly(1b) and poly(2b), the intensities of oxidation and reduction peaks decreased more than those of carbazolyl-containing poly(2a). The molar absorptivity (?) of poly(1b) at ∼700 nm increased with increasing applied voltage in the UV-vis spectrum. 相似文献
8.
Effects of internal linkage groups of fluorinated diamine on the optical and dielectric properties of polyimide thin films 总被引:2,自引:0,他引:2
To investigate the difference of the trifluoromethyl (CF3) group and ether group affecting the optical property of fluorinated polyimides (PIs), we prepared 4,4′-bis(4-amino-2-trifluoromethylphenoxy)diphenyl ether (4) with three ether groups and 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane (5) with four CF3 groups with 2-chloro-5-nitrobenzotrifluoride and 4,4′-dihydroxydiphenyl ether or 2,2-bis(4-hydroxyphenol)hexafluoropropane. Two series of organosoluble and light-colored PIs (4a-4c, 5a-5c) were synthesized from 4 and 5 with various aromatic dianhydrides: 3,3,4,4-benzophenonetetracarboxylic dianhydride (BTDA) (a), 4,4-oxydiphthalic anhydride (ODPA) (b), and 4,4-hexafluoroisopropylidenediphthalic anhydride (6FDA) (c), prepared through a typical two-step polymerization method. These PIs were soluble in amide polar solvents and even in less polar solvents. The glass-transition temperatures (Tg) of 4a-5c were 221-249 °C and the 10% weight-loss temperatures were above 530 °C. Their films had cutoff wavelengths between 339 and 399 nm and yellowness index ranges from 1.95 to 42.60. The dielectric constants estimated from the average refractive indices are 2.59-2.93 (1 MHz). In a comparison of the PI series based on 4, 5, and 4,4′-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (6), we found that the CF3 group and ether group on the diamine had almost same effect in lowering the color, but the ether group had better thermal stability. The color intensity of the three PI series was lowered in the following order: 6 > 4 > 5. The PI 5c, synthesized from diamine 5 and dianhydride c, had six CF3 groups in a repeated segment and ether group at the same time, so it exhibited the lightest color among the three series. 相似文献
9.
Chih-Cheng Lee 《Polymer》2008,49(19):4211-4217
A series of vinyl copolymers (P1-P6) containing pendant hole-transporting triphenylamine (11-88 mol%) and carbazole chromophores were synthesized by radical copolymerization to investigate the influence of triphenylamine groups upon optoelectronic properties. The copolymers were readily soluble in common organic solvents and their weight-average molecular weights (Mws) were between 1.41 × 104 and 2.24 × 104. They exhibited moderate thermal stability with Td = 402-432 °C at 5% weight loss. The emission spectra (both PL and EL) of the blends [P1-P6 with 4 wt% Ir(ppy)3] showed dominant green emission (517 nm) attributed to Ir(ppy)3 due to efficient energy transfer from P1-P6 to Ir(ppy)3. The HOMO levels of P1-P6, estimated from onset oxidation potentials in cyclic voltammeter, were −5.42 to −5.18 eV, which are much higher than −5.8 eV of conventional poly(9-vinylcarbazole) (PVK) host owing to high hole-affinity of the triphenylamine groups. The optoelectronic performances of phosphorescent EL devices, using P1-P6 as hosts and Ir(ppy)3 as dopant (ITO/PEDOT:PSS/P1-P6:Ir(ppy)3 (4 wt%):PBD (40 wt%)/BCP/Ca/Al), were greatly improved relative to that of PVK. The best performance was obtained with P4 device, in which the maximum luminance and luminance efficiency were 11?501 cd/m2 and 10.6 cd/A, respectively. 相似文献
10.
A series of phosphoryl (PO) contained compounds: triethylphosphate (a), diethylphenylphosphate (b), ethyldiphenylphosphate (c) triarylphosphates (d and h-m), triphenylphosphine oxide (e), phenyl diphenylphosphinate (f) and diphenyl phenylphosphonate (g) have been prepared. Iron catalysts, which are generated in situ by mixing the compounds with Fe(2-EHA)3 and AliBu3 in hexane, are tested for butadiene polymerization at 50 °C. Phosphates donated catalysts have been, unprecedently, found to conduct extremely high syndiotactically (pentad, rrrr = 46.1-94.5%) enriched 1,2-selective (1,2-structure content = 56.2-94.3%) polymerization of butadiene. Introduction of electron withdrawing substituents on phenyl rings oftriphenylphosphate (k-m) remarkably promotes catalytic activity, while bulky substituent isopropyl at 2-position (h) has beneficial influence on regioselectivity. Employment of e, f or g as donor, results in a suppressed monomer conversion, accompanied by deteriorated 1,2-regioselectivity. The effects of polymerization conditions such as reaction temperature, types of cocatalysts and polymerization medium are also investigated by using catalyst system with tri(2,4-difluorophenyl)phosphate (m) as donor. Highly tolerance to polymerization temperature up to 80 °C is observed for the first time in the iron-based catalyst. 相似文献
11.
Diphenylacetylenes having a dimethyloctylsilyl group and an alkyl group at para positions [Me2n-C8H17SiC6H4CCC6H4R; R = H (1a), i-Pr (1b), t-Bu (1c), n-Bu (1d)] and having only an alkyl group [PhCCC6H4R; R = i-Pr (1B), t-Bu (1C)] were synthesized and then polymerized with TaCl5/n-Bu4Sn catalyst to provide the corresponding poly(diphenylacetylene)s (2a, 2b, 2c, 2d, 2B, and 2C). The formed polymers afforded tough free-standing membranes by casting from toluene solutions. Desilylation reaction of Si-containing membranes (2a-d) was carried out with trifluoroacetic acid to give the desilylated membranes (3a-d). The permeability of these membranes to O2, N2, and CO2 were determined. All the Si-containing membranes exhibited almost the same gas permeability. The desilylation of Si-containing membranes of 2a-c resulted in large increase of gas permeability. No apparent increasing of gas permeability was observed in the desilylation of 2d. To clarify the effects of desilylation, CO2 diffusivity (D(CO2)), CO2 solubility (S(CO2)), and fractional free volume (FFV) of the polymer membranes were investigated. The S(CO2) values of desilylated membranes were much larger than that of Si-containing counterparts. The D(CO2) and FFV of membranes of 2a-c increased through desilylation. The desilylated membrane of 3d had small D(CO2) value and almost the same FFV compared with 2d. Further, the comparison of the permeability between three types of membranes with the same chemical structure revealed that the microvoids were not generated by the desilylation of membranes of poly(diphenylacetylene)s containing alkyl groups. 相似文献
12.
TEMPO-containing 7-oxanorbornene monomers 1-4 (TEMPO = 2,2,6,6-tetramethylpiperidine-1-oxy) were synthesized and polymerized via ring-opening metathesis using a ruthenium carbene catalyst. Monomers 1 and 3 gave polymers with number-average weights of 80?100 and 112?200 in 85 and 96% yields, respectively, whereas monomers 2 and 4 did not provide high molecular weight polymers. Poly(1) and poly(3) were soluble in common solvents including CHCl3, CH2Cl2 and THF, while insoluble in hexane, diethyl ether and MeOH. They were thermally stable up to ca. 240 °C according to the TGA measurements in air. The secondary batteries utilizing the present polymers as cathode-active material demonstrated reversible charge/discharge processes, whose discharge capacities were 107 and 92.8 A h/kg, and displayed excellent high-rate charge and discharge properties. These cells demonstrated excellent cycle life, e.g., the discharge capacities of poly(1) and poly(3) showed less than 10% decrements even after 100 cycles. 相似文献
13.
Baoxia Dong Aixiang Tian Jingquan Sha Li Li Hongsheng Liu 《Electrochimica acta》2007,52(11):3804-3812
Two new supramolecular assembly hexadecavanadate derivatives of H2[Cd(phen)3]2{[Cd(H2O)(phen)2](V16O38Cl)}·2.5H2O 1 (phen = 1,10′-phenanthroline) and H2[Cd(bipy)3][Cd(H2O)(bipy)2]{[Cd(H2O)(bipy)2](V16O38Cl)}·1.5H2O 2 (bipy = 2,2′-bipyridine), have been prepared under mild hydrothermal conditions and structurally characterized by IR, XPS spectra, TG analyses and single-crystal X-ray diffraction. Compounds 1 and 2 are constructed from single pendant [CdL2] (L = phen, 1 and L = bipy, 2) modified hexadecavanadates. The hybrids 1 and 2 were used as solid bulkmodifier to fabricate bulk-modified carbon paste electrodes (CPEs) (1-CPE and 2-CPE) by direct mixing. The electrochemical behaviors and electrocatalysis of 1-CPE and 2-CPE indicate bifunctional electrocatalytic activities toward both the oxidation and reduction of nitrite. Furthermore, their electrocatalytic activities toward the reduction of bromate and oxidation of ascorbic acid are also studied in 1 M H2SO4 aqueous solutions. 相似文献
14.
Novel chiral acetylene monomers bearing carbazole and triphenylamine groups, namely, (S)-3-butyn-2-yl 2-(9-carbazolyl)ethyl carbonate (1) and (S)-3-butyn-2-yl 4-(diphenylamino)benzoate (2) were synthesized, and polymerized with Rh+(nbd)[η6-C6H5B−(C6H5)3] catalyst to give the corresponding polymers with moderate molecular weights (Mn 13.0 × 103 and 15.5 × 103) in good yields (86% and 88%). CD spectroscopic studies revealed that poly(1) and poly(2) took predominantly one-handed helical structure in CHCl3. The helical structures of poly(1) and poly(2) were very stable against heating and addition of MeOH. The solution of poly(1) and poly(2) emitted fluorescence in 0.52% and 7.2% quantum yields, which were lower than those of the corresponding monomers 1 and 2 (22.5% and 76.5%). The cyclic voltammograms of the polymers indicated that the oxidation potentials of the polymers were lower than those of the monomers. The polymers showed electrochromism and changed the color from pale yellow to pale blue by application of voltage, presumably caused by the formation of polaron at the carbazole and triphenylamine moieties. The onset temperatures of weight loss of poly(1) and poly(2) were 225 and 270 °C under air. 相似文献
15.
Akito Fukui 《Polymer》2009,50(17):4159-5967
Diarylacetylenes having fluorenyl groups and other substituents (trimethylsilyl, t-butyl, bromine, fluorine) (1a-1) were polymerized with TaCl5-n-Bu4Sn. Monomers 1a-l produced high molecular weight polymers 2a-l (Mw 5.1 × 105-1.3 × 106) in 12-59% yields. All of the polymers were soluble in common organic solvents, and gave tough free-standing membranes by the solution casting method. The onset temperatures of weight loss of polymers 2a-l in air were over 400 °C, indicating considerably high thermal stability. All the polymer membranes showed high gas permeability; e.g., the oxygen permeability coefficient (PO2) of 2a was as large as 4800 barrers. Membrane 2d possessing two fluorine atoms at meta and para positions of the phenyl ring showed the highest oxygen permeability (PO2 = 6600 barrers) among the present polymers. 相似文献
16.
The guest release and solution behavior during shell disruption of a polymeric nanocapsule are described. Hyperbranched polyethylenimine (PEI, Mn = 10?000) is chemically functionalized with multiple DAD hydrogen-bonding motifs (D and A: hydrogen-bonding donor and acceptor), leading to PEI232-(DAD)x (3) (x = 93 (3a), x = 46 (3b), x = 23 (3c), x = 12 (3d)). Meanwhile, polyethylene oxide (Mn = 2 200) is end-capped with thymine moieties (PEO-ADA) (4). Mixing of the hydrogen-bonding complementary 3 and 4 (DAD/ADA = 1) leads to a physical micelle (3·4) in apolar media, and the resulting micelle can completely and irreversibly transfer the ionic and water-soluble Congo red (CR) into chloroform phase by encapsulation. Experiment proves that the micelle can exist as a pseudo-unimolecular micelle (p-UIM, meaning one PEI in one micelle) or as aggregate, depending on the shell density. As a result, 3b·4 generally exists as a p-UIM while 3d·4 can exist as p-UIM only in a very narrow range of concentrations. The critical aggregation concentration (CAC) is also dependent on the core structure of the micelle, thus when the residual amines in the core of 3b are transformed into amide, the resulting 5b·4 shows a very low CAC. Small chemicals bearing DAD hydrogen-bonding motif can compete to bind with the PEO-ADA shell and destruct the p-UIM, leading to aggregation and precipitation of the p-UIM along with the CRs. Experiment proves that the CR has strong acid-base interaction with the PEI core of the p-UIM, but when the basicity of the PEI core is reduced by amidation, partial CRs can be released into the water phase. 相似文献
17.
The electrochemical study of N-tert-butoxy-2,4-diphenyl-6-tert-butylphenylaminyl (1a), N-tert-butoxy-2,4-bis(4-chlorophenyl)-6-tert-butylphenylaminyl (1b), N-[2-(methoxycarbonyl)-2-propyl]-2,4-diphenyl-6-tert-butylphenylaminyl (2), and N-tert-butoxy-2,4,6-tris(4-chlorophenyl)phenylaminyl radicals (3) was performed by cyclic voltammetry using acetonitrile as the solvent and Bu4NPF6 as the supporting electrolyte. On cathodic scan (100 mV/s), all the radicals gave chemically reversible cyclic voltammograms, and the were determined to be −1.405 V (1a), −1.310 V (2a), −1.282 V (2b), and −1.195 V (3) (versus Fc+/Fc), respectively. On anodic scan (100 mV/s), on the other hand, 1a, 1b and 2 showed chemically reversible cyclic voltammograms, but 3 exhibited a partially reversible couple even on a scan rate of 500 mV/s, indicating that the cation species of 3 was less stable. The determined for 1a, 1b, 2 and 3 were 0.220, 0.280, 0.318 and 0.294 V (versus Fc+/Fc), respectively. The electrochemical data were compared with those of thioaminyl radicals, the corresponding sulfur analogues of 1-3. 相似文献
18.
Novel acetylene monomers containing carbazole with chiral menthyl and bornyl groups, 9-(1R,2S,5R)-menthyloxycarbonyl-2-ethynylcarbazole (1), 9-(1S,2R,5S)-menthyloxycarbonyl-2-ethynylcarbazole (2), 9-(1R,2S,5R)-menthyloxycarbonyl-3-ethynylcarbazole (3) and 9-(1S)-bornyloxycarbonyl-2-ethynylcarbazole (4) were synthesized and polymerized with a Rh catalyst to give the corresponding polymers [poly(1)-poly(4)] with moderate Mn value of (11.5-92.2) × 103 in good yields (77-89%). CD spectroscopic studies revealed that poly(1), poly(2) and poly(4) took predominantly one-handed helical structure in CHCl3, THF, toluene, and CH2Cl2, while poly(3) did not. Addition of methanol to CHCl3 solutions of poly(1) and poly(2) resulted in the formation of aggregates showing smaller CD signals at 275 and 320 nm. The helical structure of poly(1) and poly(2) was very stable against heating. The polymers emitted fluorescence in 0.40-2.90% quantum yields. Poly(4) exhibited an obvious oxidation peak at 1.10 V. The polymers were thermally stable below 300 °C. 相似文献
19.
This report describes the preparation of two new hybrid inorganic-organic polymer materials to use as electro-active layers in micro-electronic devices. By reacting poly(3-butylthiophene) (PBT) with titanium tetrachloride in a nitrogen atmosphere the hybrid inorganic-organic [(Bu-Th)2TiCl2]n (A) complex (Bu-Th = 3-butylthiophene) was prepared. {[(Bu-Th)2Ti(OH)2(H2O)2]·1.5(H2O)}n (B) was obtained by exposing A to the air. The materials’ morphology was examined by scanning electron microscopy (SEM). FT-IR studies provided information about: (a) the structural characteristics of the products; (b) the degree of polymerization; (c) the interactions occurring between the aromatic rings of PBT macromolecular ligand and the titanium metal centers; (d) the effects of the hydration process on coordination geometry of Ti complexes and on the three-dimensional structure of the resulting hybrid inorganic-organic polymer. The thermal behaviour of materials was investigated by thermogravimetry (TGA) and differential scanning calorimetry (DSC). The electrical properties of pristine PBT, A and B materials were studied by broadband dielectric spectroscopy (BDS) in the 40 Hz to 10 MHz range, and in the range of temperatures from 173 K to about 423 K. The conductivity mechanism was interpreted in terms of charge carrier hoppings between different sites followed by polymer network reorganizations both in bulk grains, and inter-grain interfaces. 相似文献
20.
A series of novel half-metallocene-type titanium complexes CpTiCl2[PhNC(R2)CHC(R1)O] (2a, R1 = Cy, R2 = CF3; 2b, R1 = tBu, R2 = CF3; 2c, R1 = Ph, R2 = CF3; 2d, R1 = Ph, R2 = CH3) have been synthesized by treating CpTiCl3 with the corresponding bidentate β-enaminoketonato ligands PhNC(R2)CHC(R1)OH in the presence of triethylamine. Single crystal X-ray diffraction revealed that complex 2b adopts distorted square-pyramid geometry around the titanium center. The complexes 2a-d were investigated as the catalysts for ethylene polymerization and the copolymerization of ethylene with norbornene. All the complexes were active towards ethylene (co)polymerization in the presence of modified methylaluminoxane, and produced high molecular weight (co)polymers. The catalytic activity and the norbornene incorporation were highly dependent upon catalyst and reaction conditions employed. Among four complexes, 2c exhibited both high catalytic activity and efficient norbornene incorporation under the same conditions, affording high molecular weight copolymers with unimodal molecular weight distributions. 相似文献