Vinyl Polymerization Of Norbornene Research Articles

Synthesis, structures, and norbornene polymerization behavior of palladium methyl complexes bearing N-heterocyclic carbene-sulfonate ligands

A series of N-heterocyclic carbene-sulfonate (NHC-sulfonate) palladium methyl complexes 2a−d were synthesized from the reaction of NHC-sulfonate ligands with Ag2O and Pd2(μ-Cl)2Me2(2,6-lutidine)2 in good yields. All these complexes were fully characterized by 1H and 13C NMR, elemental analysis, and high-resolution mass spectrometry (HRMS). The molecular structure of the representative complex 2a was also determined by single-crystal X-ray diffraction analysis. Upon activation with either methylaluminoxane (MAO) or [Ph3C]+[B(C6F5)4]−, all the palladium methyl complexes showed excellent catalytic activities [up to 108 g of polynorbornene (PNB) (mol of Pd)−1 h−1] in the vinyl polymerization of norbornene.

2-Benzoimidazol-8-alkylquinolinylnickel(II) complexes as efficient catalysts for ethylene oligomerization and vinyl polymerization of norbornene

A series of nickel complexes LNiCl2 (C1–C16), where L represents 2-benzoimidazol-8-alkylquinoline and its derivatives, were prepared as potential catalysts for the oligomerization of ethylene. The molecular structure of a representative complex C2·CH3CH2OH was determined by single-crystal X-ray diffraction. Upon treatment with diethylaluminium chloride (Et2AlCl), all nickel complex pre-catalysts exhibited good activities in the oligomerization of ethylene. Furthermore, in the presence of methylaluminoxane (MAO), the nickel pre-catalysts were suitable for vinyl polymerization of norbornene.

Synthesis, Structures, and Norbornene Polymerization Behavior of N-Heterocyclic Carbene-Sulfonate-Ligated Palladacycles

A series of new N-heterocyclic carbene-sulfonate (NHC-sulfonate) ligands 5a–e were synthesized. Treatment of the NHC-sulfonate ligands with Ag2O and palladacycles {[Pd(OAc)(8-Me-quin-H)]2 or [Pd(dmba)(μ-Cl)]2 (dmba = Me2NCH2C6H5)} yielded the desired C(sp3),N-chelated and C(sp2),N-chelated NHC-sulfonate palladacycles 6a–e and 7a–e in high yields. All these complexes were fully characterized by 1H and 13C NMR, high-resolution mass spectrometry, and elemental analysis. The molecular structures of compounds 5a, 6d, 6e, and 7e were determined by single-crystal X-ray diffraction analysis. In the presence of MAO, the C(sp3),N-chelated NHC-sulfonate palladacycles 6a–e showed excellent catalytic activities [107 g of polynorbornene (PNB) (mol of Pd)−1 h–1], while the C(sp2),N-chelated palladacycles 7a–e showed moderate catalytic activities [106 g of PNB (mol of Pd)−1 h–1] in the vinyl polymerization of norbornene. The C(sp2),N-chelated palladacycles 7a–e showed high thermal stability and reached the highest activities at high temperature (100 °C).

A novel nickel (II) complex based on a cyclam-cored generation-one dendrimeric salicylaldimine ligand and its application as a catalyst precursor in norbornene polymerization: Comparative study with some other first generation DAB-polypropyleneimine metallodendrimers

A new cyclam based first generation metallodendrimer with nickel centres on the periphery as well as at the core was synthesized by reacting a novel tetrakis(salicylaldimine) cyclam ligand with nickel acetate. The trinuclear complex was evaluated as a catalyst precursor in the vinyl polymerization of norbornene using methylaluminoxane as co-catalyst. The activity of this cyclam-based complex was compared with that of first generation DAB-PPI-salicylaldimine and DAB-PPI-pyridine-imine complexes (DAB=diaminobutane, PPI=polypropyleneimine). The cyclam based complex was found to have superior activity than both the DAB-PPI analogues as well as analogous mononuclear complexes.

Highly active 8-benzoxazolyl- or 8-benzothiazolyl-2-alkylquinolinylnickel(II) complexes for ethylene dimerization and vinyl polymerization of norbornene

The series of nickel halide complexes LNiX2 (C1–C6, X=Cl; C7–C12, X=Br), where L represents one of 8-benzoxazolyl-2-alkylquinoline or 8-benzothiazolyl-2-alkylquinoline derivatives, have been prepared. The molecular structures of the representative complexes C1, C3, C6 and C11 were determined by single crystal X-ray diffraction. Upon activation with ethylaluminium sesquichloride (EASC), all nickel complex pre-catalysts exhibited good activities for ethylene dimerization. Furthermore, such nickel pre-catalysts, in the presence of methylaluminoxane (MAO), were capable of the vinyl polymerization norbornene.

Vinyl Polymerization of Norbornene on Nickel Complexes with Bis(imino)pyridine Ligands Containing Electron-Withdrawing Groups

A series of novel bis(imino)pyridine nickel(II) dichloride complexes, with the bis(imino)pyridine ligands containing electron-withdrawing groups (F, Cl, Br, CF3), have been prepared and characterized by elemental analysis and NMR spectroscopy. All complexes exhibit paramagnetically shifted 1H NMR spectra, indicative of the high-spin (S = 1) state of the d8 nickel(II) central atom. These complexes have been found to be highly active catalysts of vinyl-type norbornene polymerization upon activation with MAO, displaying activities up to 1.16 × 107 g of PNB (mol of cat.)−1 h–1 (the highest ever reported for norbornene polymerizations on bis(imino)pyridine nickel complexes) and yielding high-molecular-weight polynorbornene (Mw up to 4.5 × 106). X-ray structures for some of the nickel complexes are reported.

Steric and Electronic Effects of Tetradentate Nickel(II) and Palladium(II) Complexes toward the Vinyl Polymerization of Norbornene

A series of Ni(II) and Pd(II) complexes bearing N4-type tetradentate ligands, [Ni(-6-) 1] and [Pd(-6-) 2]; 6- = N,N'-(o-phenylene)bis(6-methylpyridine-2-carboxamidate), = Cl, H, or , = , Cl, F, H, , or ) were designed, synthesized, and characterized to investigate electronic and steric effects of ligand on the norbornene polymerization catalysts. Using modified methylaluminoxanes as an activator, the complexes exhibited high catalytic activities for the polymerization of norbornene and the nickel complexes exhibited better catalytic activity the palladium complexes. Ni complex 1a with group on the benzene ring showed the highest catalytic activity of g of PNBEs/ and molecular weight of g/mol with PDI 100 ), and tend to afford higher polymerization productivities than the ones having electron-donating groups. Amorphous polynorbornenes were obtained with good solubility in halogenated aromatic solvents. A vinyl addition mechanism has been proposed for the catalytic polymerization.

Bis(β-ketoamino) copper complexes for vinyl polymerization of norbornene: Correlation between precursor structure and catalytic activity

A novel fluorinated bis(β-ketoamino) copper complex was synthesized and characterized. Norbornene polymerizations with bis(β-ketoamino) copper complexes activated with methylaluminoxane (MAO) were investigated. The highest catalytic activity up to now reported for copper based systems in norbornene polymerization was achieved using fluorinated bis(β-ketoamino) copper/MAO. The influence of precursor structure including steric and electronic effects on catalytic activity for norbornene polymerization was evaluated in detail. Bulky steric substituents and strong electron-withdrawing groups can enhance catalytic activity of precursor for norbornene polymerization through a dissociative mechanism. The influences of polymerization parameters such as polymerization temperature and Al/Cu ratio on norbornene polymerization with bis(β-ketoamino) copper catalysts were also examined. Norbornene polymerization catalyzed by bis(β-ketoamino) copper complexes/MAO proceeded on Cu(I) species through a coordination/insertion mechanism to produce vinyl-addition polynorbornene.

2-(N-Alkylcarboxamide)-6-iminopyridyl palladium and nickel complexes: coordination chemistry and catalysis

The 2-(N-alkylcarboxamide)-6-iminopyridine ligands (L1-L7) can bind as either mono-anionic tridentate N^N^N ligands on reaction with PdCl(2)(CH(3)CN)(2), to form complexes LPdCl (C1-C7), or as neutral tridentate N^N^O ligands with NiCl(2)·6H(2)O, to produce complexes LNiCl(2) (C8-C14). All metal complexes were characterized by IR spectroscopy and elemental analysis, and in the case of the palladium complexes, by (1)H and (13)C NMR spectroscopy. The crystal structures of C3, C4, C6, C10, and C12 were determined by X-ray crystallography, and revealed a distorted square geometry around the palladium centre, whereas for nickel, a distorted square-pyramidal geometry was adopted. The representative palladium complex (C3) was further reacted with AgBF(4) in acetonitrile affording the salt [L3Pd(CH(3)CN)][BF(4)] (C15) and the structure of this was confirmed by single-crystal X-ray diffraction. By contrast, carrying out the reaction in dichloromethane rather than acetonitrile, in the presence of malononitrile (CNCH(2)CN), resulted in the formation of the bimetallic palladium complex [L3Pd(CNCH(2)CN)PdL3]·2[BF(4)] (C16). Upon activation with diethylaluminium chloride, all the nickel complexes showed high activity for ethylene dimerization. Furthermore, the palladium complexes exhibited good activities in the vinyl-polymerization of norbornene upon activation with MAO.

Oligomers and soluble polymers from the vinyl polymerization of norbornene and 5-vinyl-2-norbornene with cationic palladium catalysts

Oligomeric vinyl polynorbornene (2 to ∼12 monomer units) was obtained via hydrooligomerization of norbornene (NB) using the cationic palladium complexes [Pd(PPh 3) n (NCCH 3) 4− n ](BF 4) 2 [ n = 0 ( 1), 3 ( 2)] at different hydrogen pressures. The vinyl polymerization of norbornene (NB) in the ionic liquid N-butyl- N-trimethylammonium bis(trifluoromethylsulfonyl)imide (BtMA +NTf 2 −) with [Pd(NCCH 3) 4](BF 4) 2 led to soluble polynorbornenes (with several hundred monomer units) at different temperatures and molar NB:Pd ratios. The norbornene derivative 5-vinyl-2-norbornene (VNB) was oligomerized in high yield with 1 in CH 3NO 2 primarily through the (endocyclic) norbornene double bond but also through both the norbornene and (exocyclic) vinyl double bond for about every second monomer (by 1H NMR). A 2D 1H, 13C-HSQC NMR analysis suggests a β-hydrogen elimination after insertion of a norbornene double bond as chain-termination mechanism. The conversion of NB or VNB increased with temperature and a lower NB:Pd and VNB:Pd ratio, respectively. The vinyl double bond in VNB slowed down the insertion rate drastically when compared with NB (activity decrease by a factor of 10 2).

Synthesis and characterization of tridentate phenoxy-imine ligand [N,N,O] nickel(II) and palladium(II) complexes and their catalytic behaviors in vinyl polymerization of norbornene

In this study, new complexes LNiCl(1), LNiBr(2), LNiI(3), and LPdCl(4) (L = 4,6-di-tert-butyl-2-(N-(quinolin-8-yl)iminomethyl)phenolato) have been synthesized and characterized. X-ray diffraction studies on Complexes 1 and 4 revealed that N, N, O, and halogen atoms coordinated to metal, with a nearly square planar geometries in all cases. All these complexes are robust and exhibit high activities for the addition polymerization of norbornene (NB) with methylaluminoxane as cocatalyst [up to 47.62 kg PNB(mmol of Ni)−1h−1] and also lead to various activities and molecular weights of polynorbornenes under different reaction conditions. It is noteworthy that Complexes 1 and 4 show better activity under higher reaction temperature of 80°C. However, Complex 2 showed lower activity, and Complex 3 was found nearly inert toward NB polymerization, probably, because of thermal instability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Vinyl polymerization of norbornene with bis(imino)pyridyl nickel(II) complexes

AbstractA series of different steric hindrance nickel(II) complexes 1–6 bearing 2,6‐bis(imino)pyridine ligands have been synthesized and characterized. The molecular structures of the complexes 3–5 were determined by X‐ray diffraction analysis. The coordination geometry around the nickel center of the complexes is either square pyramid for complexes 3 and 4 or trigonal bipyramid for complex 5. All of the nickel complexes exhibit high catalytic activity for norbornene polymerization in the presence of MAO, although low activity for ethylene oligomerization and polymerization. The effects of the Al/Ni ratio, halogen, monomer concentration, temperature, and reaction time on activity of catalyst for norbornene polymerization and polymer microstructure were investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

VINYL POLYMERIZATION OF NORBORNENE CATALYZED BY [2-(2-BENZIMIDAZOLYL)-6-((1-ARYLIMINOETHYL)PYRIDYL)]NICKEL CHLORIDE/MAO SYSTEM

The catalytic system of (2-(2-benzimidazolyl)-6-((1-aryliminoethyl)pyridyl))nickel chloride/MAO (methylalu- minoxane) was found to be good active for vinyl polymerization of norbornene and provided polymers with relative narrow molecular distributions. Various reaction parameters, such as the ratios of nickel precursor to MAO or monomer norbornene, and the nature of the ligands in complexes were carefully investigated to realize their effects on the catalytic activities, polymer molecular weight and molecular weight distributions.

Vinyl polymerization of norbornene by mono‐ and trinuclear nickel complexes with indanimine ligands

AbstractA series of new indanimine ligands [ArNCC2H3(CH3)C6H2(R)OH] (Ar = Ph, R = Me (1), R = H (2), and R = Cl (3); Ar = 2,6‐i‐Pr2C6H3, R = Me (4), R = H (5), and R = Cl (6)) were synthesized and characterized. Reaction of indanimines with Ni(OAc)2·4H2O results in the formation of the trinuclear hexa(indaniminato)tri (nickel(II)) complexes Ni3[ArN = CC2H3(CH3)C6H2(R)O]6 (Ar = Ph, R = Me (7), R = H (8), and R = Cl (9)) and the mononuclear bis(indaniminato)nickel (II) complexes Ni[ArNCC2H3(CH3)C6H2(R)O]2 (Ar = 2,6‐i‐Pr2C6H3, R = Me (10), R = H (11), and R = Cl (12)). All nickel complexes were characterized by their IR, NMR spectra, and elemental analyses. In addition, X‐ray structure analyses were performed for complexes 7, 10, 11, and 12. After being activated with methylaluminoxane (MAO), these nickel(II) complexes can polymerize norbornene to produce addition‐type polynorbornene (PNB) with high molecular weight Mv (106 g mol−1), highly catalytic activities up to 2.18 × 107 gPNB mol−1 Ni h−1. Catalytic activities and the molecular weight of PNB have been investigated for various reaction conditions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 489–500, 2008

The Advantages of Metal Complexes as Catalysts toward Polyolefins ‐ The Vinyl Polymerization of Norbornene

AbstractVarious nickel complexes bearing [N,O], [P,N] ligands as well as the supported nickel complexes were prepared and showed moderate to high catalytic activities for vinyl polymerization of norbornene. The formed polynorbornenes (PNBs) are soluble for measuring both the molecular weights and the molecular weight distributions. Comparing the results in homogeneous catalysis, the PNBs produced by supported catalysts possessed higher molecular weights and slightly broader molecular weight distributions. The reactor fouling generally happens in homogeneous catalytic systems, while spherical polymer particle morphology could be obtained without reactor fouling by using MgCl2‐supported nickel catalysts.

Vinyl polymerization of norbornene with nickel catalysts bearing [ N, N] six-membered chelate ring: Important influence of ligand structure on activity

Norbornene polymerizations with nickel complexes bearing [ N, N] six-membered chelate ring activated with methylaluminoxane were investigated. The influence of ligand structure such as β-diimine, β-diketiminate, fluorinated β-diketiminate, and anilido-imine ligand on catalytic activities for norbornene polymerization was evaluated in detail. Ligands led to different electrophilicity of the nickel metal center, and a relatively positive nickel metal center would result in high catalytic activities for norbornene polymerization. The influences of polymerization temperature and Al/Ni ratio on norbornene polymerization with nickel catalysts bearing β-diimine, β-diketiminate, and fluorinated β-diketiminate ligands were also examined. All of the obtained polymers catalyzed by these nickel catalysts bearing [ N, N] ligand are vinylic addition polynorbornenes with different molecular weights.

Vinyl polymerization of norbornene by nickel(II) complexes bearing β‐diketiminate ligands

AbstractNorbornene polymerizations were carried out using nickel(II) bromide complexes CH{C(R)NAr}2NiBr (1, R = CH3, Ar = 2, 6 − iPr2C6H3; 2, R = CH3, Ar = 2, 6‐Me2C6H3; 3, R = CF3, Ar = 2, 6 − iPr2C6H3; 4, R = CF3, Ar = 2, 6‐Me2C6H3) in the presence of methylaluminoxane. Compound 3 is the most active norbornene polymerization catalyst of all the nickel complexes tested. The activity of theses catalysts increases with increases in steric bulk of the substituents on the aryl rings. The electronic nature of the ligand backbone also affects the activity. The resulting polynorbornenes are vinyl type by IR and NMR analyses. Copyright © 2007 John Wiley & Sons, Ltd.

A copper complex with β-ketoamine ligand based on pyrazolone derivative: synthesis, crystal structure and catalysis for norbornene polymerization

A copper complex with β-ketoamine ligand based on a pyrazolone derivative was synthesized by condensing pyrazolone with 3-methylaniline and then reacting the produced β-ketoamine with copper halide. The solid-state structure of the complex was determined by single-crystal X-ray diffraction. The bis(β-ketoamine) copper complex shows moderate activity to catalyze the vinyl polymerization of norbornene with activation of methylaluminoxane under mild reaction conditions. The activity of the catalyst for norbornene polymerization is as high as 2.88 × 104 g polymer/mol Cu h. The polymer yield and catalytic activity can be controlled over a wide range by the variation of reaction parameters.

Polymerization of norbornene using novel palladium carboxylate/boron trifluoride etherate catalyst system

The vinyl polymerization of norbornene with Pd(carboxylate) 2/BF 3OEt 2 catalyst system has been investigated by varying the molar cocatalyst/metal ratio, the norbornene/metal ratio, the metal concentration and the reaction temperature. The effects on the catalyst activity were explained on the basis of complexation equilibrium for the active homogeneous complex. A “particular” activity of 154 100 kg NB per mole Pd for an hour has been achieved at B/Pd = 25 and 25 °C. The molecular weights M w from 77 700 to 293 800 g/mol and glass transition temperatures T g from 240 to 262 °C were observed for the representative samples of polynorbornene. The molar mass distribution indicates a single-site, highly homogeneous character of the active catalyst species. Catalytic activity and polymer molecular weight can be controlled by varying the reaction parameters over a wide range. NMR and IR spectroscopic studies of the polymer showed 2,3-enchained repeating units of polymer backbone with low diisotacticity. The simplicity of catalyst system composition might be of industrial importance.

Vinyl polymerization of norbornene over supported nickel catalyst

AbstractA series of nickel complexes, bis(salicylideneiminato)nickel(II), were supported on spherical MgCl2 and SiO2. Scanning electron microscopy, energy‐dispersed X‐ray spectroscopy, and the BET method for surface areas measurements were utilized to examine the supporting process of the catalysts. The particle morphology of the original support is retained and replicated throughout the supported catalyst preparation and norbornene polymerization. Spherical polymer particle morphology was achieved, without reactor fouling. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2233–2240, 2006