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A series of mono- and polynuclear bis(phenoxy-imine) titanium and zirconium complexes were synthesized. The complexes were immobilized on an MgCl2 carrier prepared by different methods. The homogeneous complexes and supported catalysts were evaluated for ethylene polymerization. The effects of the nuclearity of the precatalysts, nature of organoaluminum activator and the polymerization temperature were examined. It has been shown that immobilized on MgCl2 catalysts are superior in activity to homogeneous precatalysts by the level of activity (up to 6.1 ton of PE (molM h atm)−1). The precatalysts obtained in situ by the interaction of FI complexes, Bu2Mg and Et2AlCl are suitable for preparing ultra-high molecular weight polyethylene (UHMWPE) with molecular weight up to 6 106 Da even at elevated reaction temperatures. In addition, supported precatalysts, in the presence of MAO, effectively catalyze the ethylene–higher olefin copolymerization (activity—up to 8.2 ton of copolymer (molM⋅h⋅atm)−1).

A series of bis(phenoxy-imine) (FI) titanium(IV) and zirconium(IV) complexes have been synthesized. The effect of the nature of the activator (MAO, combinations EtnAlCl3-n + Bu2Mg and iBu3Al + [Ph3C]+[B(C6F5)4]−) on the catalytic activity and properties of the resulting polymers was studied. It was found that Ti-Fi complexes, despite the nature of the outgoing ligands (Cl or iPrO) in the presence of Al/Mg activators, effectively catalyze the polymerization of ethylene (with the formation of UHMWPE); copolymerization of ethylene with 1-octene (with the formation of ultra-high molecular weight copolymers); and the ternary copolymerization of ethylene, propylene and 5-vinyl-2-norbornene (with the formation of polyolefin elastomers). It has been shown that Zr-FI complexes are not activated by these Al/Mg compositions. The resulting UHMWPE can be processed by a solventless method into high-strength and high-modulus oriented films; however, their mechanical characteristics do not exceed those obtained using MAO.

Ethylene/1-hexene copolymerization was carried out with a new Ti (IV) complexes stabilized by fluorinated 2-hydroxymethylphenol derivatives and activated by MAO-free binary cocatalysts—{alkyl aluminum chloride + Bu2Mg}. Structures and properties of the obtained copolymers were measured by DSC, GPC and 13C NMR. The effects of the ligand structure and the nature of organoaluminum activator on the polymer yield, comonomer incorporation, polymer composition, molecular weight, polydispersity index and stress–strain behavior have been investigated. The results indicated that the complex with adamantyl substituent was the most active in this series. The obtained copolymer exhibited the highest 1-hexene incorporation content of 18.9 mol%

The synthesis and olefin polymerization behavior of a new TADDOL-based Ti(IV) complex, (4R,5R)-2,2-dimethyl-α,α,α′,α′-tetrakis[bis-(3,5-trifluoromethyl)phenyl]-1,3-dioxolane-4,5-dimethanolato-titanium(IV) dichloride, are described. Upon activation with MAO, this complex polymerized ethylene, producing ultra-high molecular weight linear polyethylene (UHMWPE) with activities up to 4500 kg mol (Ti)−1 [C2H4]−1 h−1 atm−1 and molecular weights up to 3.25 × 106. The optimal temperature for UHMWPE synthesis was 50 °C. This complex is also capable of copolymerizing ethylene with 1-hexene and 1-octene, giving high molecular weight copolymers with α-olefin incorporation up to 7.8%. The copolymers, obtained with a different ratio of comonomers, are statistical, according to the analysis of the 13C NMR spectra. The reaction parameters that influenced the copolymerization behavior, such as comonomer concentration, reaction temperature and [Al]/[Ti] molar ratio, are examined in detail. Furthermore, high catalytic activities up to 12,531 kg mol(Ti)−1 [C2H4]−1 h−1 atm−1 were observed in copolymerization of ethylene and 1-hexene or 1-octene with the 2/MAO catalytic system. The obtained copolymers possess high molecular weights (Mw = 1.4 × 106—ethylene/1-hexene and 1.86 × 106—ethylene/1-octene) with broad MWD (Mw/Mn = 3.04–8.23) and high comonomer incorporation degrees (up to 6.2 mol% of 1-hexene and 7.8 mol% of 1-octene). Depending on the synthesis conditions, it is possible to form both a statistical copolymer and a block copolymer.

A novel C N bond forming strategy based on oxo/imido heterometathesis between N-sulfinylamines and ketones, catalyzed by a well-defined silica-supported Ti imido complex, was applied to prepare a series of hardly accessible 1,1’-diacetylferrocene ketimines.

In order to increase the thermal stability of olefin polymerization precatalysts, new titanium(IV) complexes with diolate ligands differing in the degree of steric hindrances were synthesized from readily available precursor (±)camphor. The structures of the complexes 1–2 were established by X-ray diffraction. Complexes 1–4 in the presence of an activator {EtnAlCl3-n + Bu2Mg} catalyzed the synthesis of UHMWPE with an Mv up to 10 million and a productivity of up to 3300 kg/molTi·atm·h. The obtained polymers are obviously characterized by a low density of macromolecular entanglement, which makes it possible to use the solid-phase method for their processing. The mechanical characteristics of the oriented UHMWPE films had a breaking strength up to 2.7 GPa and an elastic modulus of up to 151 GPa. The precatalysts 1–4 were also active in ethylene/1-octene copolymerization. The comonomer content was in the range of 1.4–4.6 mol%. The use of a rigid linker and an increase in the steric load of the diolate complexes ensured the thermal stability of the catalytic system in the range of 50–70 °C.

Nickel(II) complexes with pyrazole-based ligands are widely employed in catalysis of ethyleneoligomerization and subsequent Friedel-Crafts alkylation of toluene. We have prepared ten newnickel(II) dibromide complexes with various substituted bis(azolyl)methanes. They have beencharacterized using 1H NMR, IR, MALDI-TOF and elemental analysis. The structures of threecomplexes have been unambiguously established using X-ray diffraction. It was found that thesecomplexes in the presence of Et2AlCl or Et3Al2Cl3 are active both in ethylene oligomerization andFriedel-Crafts alkylation processes (activity up to 3720 kgoligomer·mol[Ni]−1·h−1). The use of Et3Al2Cl3results in the higher share of alkylated products (up to 60%). Moreover, catalytic systems activated withEt3Al2Cl3 produced small amounts of odd carbon number olefins (up to 0.8%). The Friedel-Craftsalkylation was used as a trap for previously undetected short-chain odd carbon number olefins (C3 andC5).

Four new coordination compounds of nickel (II) with derivatives of N,N-bis(pyrazol-1-ylmethyl)propylamine were synthesized; their composition and structure were confirmed with IR-spectroscopy and elemental analysis. The structures of products 13 and 15 were unambiguously established in an X-ray diffraction study. Compounds 13 and 15 crystallize in the orthorhombic space groups Pna21 and P212121 correspondingly and represent a monomeric octahedral nickel complexes, that are typical for tridentate scorpion-type ligands. New method for immobilization of nickel complexes with derivatives of N,N-bis(pyrazol-1-ylmethyl)propylamine on silica gel modified with aminopropyl groups was proposed. The EXAFS/XANES analysis indicated that Ni atom in the supported complexes adopt almost octahedral geometry, being partly surrounded by nitrogen atoms from organic ligand and partly grafted to silica surface through silanol groups, with Br− in outer coordination sphere. Both the original and the supported complexes, when activated with Et2AlCl or Et3Al2Cl3, catalyze ethylene oligomerization with the predominant formation of butene isomers. Generally, the immobilized complexes show higher activity and better selectivity towards 1-butene formation.

Binuclear and hexanuclear titanium complexes stabilized by tetradentate [OOOO]4–-type ligand were active in ethylene polymerization in the presence of Et2AlCl/Bu2Mg binary co-catalyst, giving high molecular weight polyethylene. The binuclear complex showed significantly higher catalytic activity and thermal stability in comparison to mononuclear analogue. Ultra high molecular weight polyethylene (UHMWPE) samples were processed by a solid-state uniaxial deformation into high-strength (up to 2.5 GPa) and highmodulus (over 100 GPa) oriented film tapes, which indirectly indicates a low degree of entanglements between the macromolecular chains.

A series of titanium (IV) complexes 3a-f stabilized by 1,2-diolate ligands 2 a-e have been synthesized. Structures of complexes 3d and 3e have been determined by X-ray diffraction. Titanium atoms in these complexes have a distorted square-pyramidal environment. All resulting complexes are highly active in ethylene polymerization in the presence of {3Et2AlCl + MgBu2} or {1.5Et3Al2Cl3 + MgBu2} binary co-catalysts. In the latter case, higher molecular weights of UHMWPE samples (up to 7.7 106) are achieved. Obtained polymers are suitable for the modern processing methods – the solvent-free solid state formation of super high-strength (over 2.0 – 2.8 GPa) and high-modulus (up to 145 GPa) oriented film tapes.

A series of titanium (IV) complexes (2, 5-7) stabilized by a substituted 2-hydroxybenzyl alcohols (1, 4) – were synthesized. Structures of complexes 6-7 were determined by X-ray diffraction. Titanium atom in the tetrameric complex 6 has an octahedral environment created by chlorine atom and five oxygen atoms. The main structural feature of 7 is a centrosymmetric Ti4O6 cage which is built of two seco-norcubanes Ti4O3 sharing a common Ti2O2-face. A coordination polyhedron around the titanium atoms is the distorted octahedron, with the long Ti─μ-O and short Ti─O bonds. All resulting complexes are moderately or highly active in ethylene polymerization in the presence of {3Et2AlCl + Bu2Mg} binary co-catalyst. Resulting polymers are linear ultrahigh molecular weight polyethylenes (up to 7.9 106 g/mole). Polymers are suitable for the modern processing methods – the solvent-free solid state formation of super high-strength (tensile strength over 2.0–2.4 GPa) and high-modulus (elastic modulus up to 130 GPa) oriented film tapes.

The reaction of 3-formylchromones and 4-((2-aminophenyl)imino)-2,6-di‑tert-butylcyclohexa-2,5-dienone gave a series of N-substituted benzimidazole derivatives, characterized by 1H and 13C NMR spectroscopy, mass spectrometry and elemental analysis. The molecular structures of compounds 1 and 4 were determined by single crystal X-ray diffraction studies. Compounds 1–8 exhibit cytotoxic activity against human colon cancer cells HCT116 and breast cancer cells MCF7 at submicromolar concentrations. Compound 6 is more active against tumor cells than non-malignant fibroblasts. Compounds 1, 3, 5 and 7 exhibit antioxidant activity comparable to the reference drug Trolox.

Synthetic derivatives of flavonoids are a promising class of biologically active compounds. Here we report a family of (chromon-3-yl)-bis(3,5-dimethylpyrazol-1-yl)methanes bearing various substituents in chromone fragment. They have been studied for the antioxidant activity and spectra of their biological activity have been predicted. New Ni(II), Co(II) and Pd(II) complexes, supported by 3-[bis(3,5-dimethylpyrazol-1-yl)methyl]-6-fluoro-chromen-4-one, have been synthesized and characterized using 1H NMR, high-resolution MALDI-TOF spectrometry and elemental analyses. The molecular structures of 3-[bis(3,5-dimethylpyrazol-1-yl)methyl]-chromen-4-one 1, 3-[bis(3,5-dimethylpyrazol-1-yl)methyl]-6‑chloro-chromen-4-one 7 and Co dichloride complex with 3-[bis(3,5-dimethylpyrazol-1-yl)methyl]-6-fluoro-chromen-4-one 15 have been determined using single crystal X-ray diffraction studies. The cytotoxic activity of metal complexes and the ligand 1 has been studied on 4 cell lines of different histological origin. It has been observed that Ni complex exhibits higher cytotoxicity against breast cancer cells MCF7 and Co complex has almost the same effect on the growth of all studied tumor cells.

Polymerization reactions of ethylene, propylene, higher 1-alkenes (1-hexene, 1-octene, 1-decene, vinyl cyclohexane, 3-methyl-1-butene), and copolymerization reactions of ethylene with 1-octene with a post-metallocene catalyst containing an oxyquinolinyl complex of Ti and a combination of Al(C2H5)2Cl and Mg(C4H9)2 as a cocatalyst were studied. The catalyst is highly active and, judging by the broad molecular weight distribution of the polymers, contains several active center populations. The active centers differ not only in their kinetic parameters but also in stereospecificity. Most of the active centers produce essentially atactic polypropylene but a small fraction of the centers produces polypropylene of moderate isotacticity degree. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1844–1854

Novel heteroscorpionate ligands were synthesized by a Peterson rearrangement during the reaction of 2-pyridinecarboxaldehyde (or 2-quinolinecarboxaldehyde) and 1,1-carbonyl-bis(pyrazoles). Nickel(II) dibromide reacts with these ligands in THF to give the heteroscorpionate dibromo complexes of general formula LNiBr2. Crystal structures of two full-sandwich heteroscorpionate Ni(II) complexes were determined. Preliminary studies of catalytic activity in ethylene oligomerization using different organoaluminum cocatalysts were performed. The addition of one equivalent of triphenylphosphine resulted in increased catalytic activity for most examples. The catalyst system of (2-[bis(3,5-dimethylpyrazol-1-yl)methyl]pyridine nickel(II) dibromide/Et2AlCl/PPh3 dimerized ethylene with an activity of 650 g oligomer mol−1 Ni h−1 while the share of 1-butene in the mixture has reached 75%. Tris(3,5-dimethylpyrazol-1-yl)methyl nickel(II) dibromide, activated by Et2AlCl/PPh3 produced isobutylene (75% of the butene fraction).

A series of oxovanadium (V) and titanium (IV) complexes stabilized by [ONO]2− type ligands-2-[hydroxy(diaryl)methyl]-8-hydroxyquinolines (2–3) were synthesized in high yields and characterized by elemental analysis, NMR-, IR spectroscopy and mass spectrometry. The molecular structures of the representative complexes 4 and 7 were confirmed by single-crystal X-ray diffraction, and revealed distorted octahedral geometry at Ti and tetragonal pyramid in V complex. Titanium-based catalytic systems were found to be active in the ethylene and 1-hexene polymerization and copolymerization, but only in the presence of a binary co-catalyst Et2AlCl/Bu2Mg. Vanadium-based systems were active in the same reactions in the presence of Et3Al2Cl3 or Et2AlCl mixed with CCl3CO2Et reactivator. The amount of co-monomer incorporated by these systems have reached 23 mol%. When applied in the presence of aliphatic solvents vanadium complexes catalyze 1-hexene oligomerization yielding dimers and trimers. When the same process is carried out in toluene, the solvent got alkylated by monomers and light oligomers (Friedel–Crafts reaction).

A series of titanium(IV) complexes (2–6) stabilized by a substituted 2-hydroxymethylphenole (1) – were synthesized and characterized by NMR- and IR-spectroscopy. Structures of complexes 5–6 were established by X-ray diffraction. Titanium atom in the dimeric complex 5 has an octahedral environment created by chlorine atoms and five oxygen atoms. In the tetrameric complex 6 coordination polyhedra of Ti(1) atom is trigonal bipyramid and in Ti(2) – tetragonal pyramid with the environment of five oxygen atoms. Each complex contains alkoxo-groups and/or a chlorine atom easily leaving during treatment with magnesium- or organoaluminum compounds. All resulting complexes are moderately or highly active in ethylene polymerization in the presence of {3Et2AlCl + Bu2Mg} binary co-catalyst. Complexes 5 and 6 are significantly superior to previously described analogs 2–4 in thermal stability and catalytic activity. Resulting polymers are linear polyethylenes of high and ultrahigh molecular weight (over 2.5 · 105 g/mole) with a broad molecular weight distribution. Polymers are suitable for the modern methods of polymer processing – the solventless solid state formation of super high-strength (breaking strength over 1.5 GPa) and high-modulus (elastic modulus over 60 GPa) oriented films and film tapes.

In this work we describe synthesis of new chloride and alkoxo-titanium (IV) complexes 3–7 with diol O,O-type ligands from readily available and scalable precursors. Structure of complex 6 was established by X-ray diffraction. Titanium atom adopts a tetrahedral geometry formed by three oxygen atoms of ligands and one oxygen atom of isopropoxo group. The resulting complexes 3–6 are moderately or highly active in ethylene polymerization in the presence of {3Et2AlCl + Bu2Mg} binary co-catalyst. Obtained polymers are linear polyethylene of ultrahigh molecular weight (3.7–8.8·106 g/mole) with a broad molecular weight distribution. Polymers are suitable for the modern methods of polymer processing - the solventless solid state formation of super high-strength (breaking strength over 2.3 GPa) and high-modulus (elastic modulus over 150 GPa) oriented films and film tapes.

Three α-diimine complexes of NiII of the general formula {2,3-bis[N,N-(aryl)imino]butane}NiBr2 with aryl groups 2,3,5,6-F4-C6H, 2-CF3-C6H4 and 2,4-(CH3)2-C6H3 were synthesized and used as catalyst precursors in oligomerization reactions of ethylene and propylene. Oligomerization catalysts were produced by activating the complexes with AlEt2Cl, Al2Et3Cl3, and with combinations of these compounds and PPh3. The catalysts convert ethylene into low molecular-weight materials (liquids and waxes) with oligomer chains containing 15–20 mol.% of methyl branches and 4–6 mol.% of ethyl branches, which are apparently produced in “chain-walking” reactions of active centers along oligomer chains. Oligomerization of propylene yields a variety of light products, mostly dimers, which are formed in primary and secondary insertion reactions of propylene into Ni–H and Ni–C bonds in active centers. Reaction schemes of oligomer formation are discussed.

A new α-diimine-type ligand – 1 was synthesized and fully characterized. It reacted with NiBr2 to form the corresponding complex which was characterized by elemental analysis, NMR and infrared spectroscopy. According to the X-ray complex crystallizes from aqueous methanol as the hydrated dimer with ionic structure (L2Ni2Br3·2Н2О)+Br− and distorted octahedral environment of nickel atoms. Pre-catalyst, activated with either Et3Al2Cl3 or Et2AlCl, showed good activities in ethylene oligomerization. Notably high selectivity to α-olefins was achieved in the presence of Et3Al2Cl3. The addition of PPh3 to the Ni(II)-based systems enhanced the catalytic activity and switched the selectivity from terminal to internal olefins.

Vanadium(V) imido complexes are widely used in olefin polymerization and oligomerization. In this report we present the synthesis and the results of ethylene polymerization studies for a series of vanadium(V) imido complexes with various substituents at the imido fragment. All complexes have been prepared in nearly quantitative yields by the interaction of N-sulfinylamines with VOCl3 or VO(OnPr)3 and characterized using 1H, 13C, 51V NMR and elemental analysis. The solid-state structure of complex V(=NArOMe)(OnPr)3 was established using X-ray. Vanadium(V) imido chlorides and n-propoxides exhibited similar moderate catalytic activities (320–547 kgPE·mol(V)−1·h−1·atm−1). The maximum catalytic activity (547 kgPE·mol(V)−1·h−1·atm−1) was achieved for (adamantylimido)vanadium(V) n-propoxide. The molecular weights of the resulting polyethylenes were higher (Mv = 3.7–6.5·105 Da) for imido n-propoxide complexes as compared to the corresponding imido chlorides (Mv = 2.1–5.5·105 Da). The localization of DFT calculated HOMO on imide nitrogen was proposed to favor the reaction between imide ligand and Et2AlCl used as activator.

Nickel(II) complexes with neutral bidentate nitrogen-containing ligands are of great interest as promising precatalysts for the selective oligomerization of ethylene. Complexes of compositions 0.75[LNiCl2]2•0.25[LNiClBr]2 2 and LNiBr2 3 where L = bis-(3,5-dimethylpyrazol-1-yl)methane have been synthesized and characterized by single crystal X-ray diffraction, IR and 1H NMR spectroscopies and elemental analysis. The 1H NMR spectra of paramagnetic complexes indicate that the structures of these complexes in solution are similar to ones in the solid state. Magnetic susceptibility of the compounds has been investigated and discussed in the context of their structures. Treatment of these complexes with diethylaluminum chloride (DEAC) or ethylaluminum sesquichloride (EASC) generates active catalysts that oligomerize ethylene to yield mostly butenes with activities up to 930 kg(oligomers)·mol[Ni]−1·h−1 (DEAC).

New heterobimetallic Ti(IV)–Ca and Ti(IV)–Ba complexes stabilized with fluorinated ligand – 2-[bis-CF3-hydroxymethyl]-4,6-tert-butylphenol have been synthesized; their compositions and structures have been confirmed by NMR, IR-spectroscopy and elemental analysis. The solid-state structures of complexes 1–2 were established by X-ray analysis. These complexes catalyze ethylene polymerization in the presence of a binary cocatalyst {3Et2AlCl + Bu2Mg}. In the result of this reaction Ultra High Molecular Weight Polyethylene (UHMWPE) with a broad molecular weight distribution is obtained. UHMWPE samples were processed into high-strength (up to 2.4 GPa) and high-modulus (over 130 GPa) oriented film tapes by a solid-state uniaxial deformation. Such parameters of UHMWPE samples indirectly indicate a low degree of entanglements between the macromolecular chains. The effect of the pre-catalysts composition on the catalytic activity and properties of the obtained polymer has been investigated.

Novel bi- and hexanuclear titanium (IV) complexes with 2,2′-bis-(hydroxymethyl)-1,1′-biphenole derivative were synthesized. Structure of complexes 4–5 were established by X-ray diffraction. Resulting catalytic systems obtained by pre-catalysts activation by diethylaluminum chloride or ethyl aluminum sesquichloride were active in the 1-hexene oligomerization. Replacement of alkylaluminumchlorides by a {3Et 2 AlCl + Bu 2 Mg} binary system results in formation of predominantly isotactic, high molecular weight poly-1-hexene (content of isotactic pentad mmmm 70%). Systems treated with “traditional” activators – MAO and AlR 3 were not active.

A series of oxovanadium (IV, V) complexes stabilized by [OON]2- type ligand – 7- (hexafluoro-2-hydroxypropane-2-yl)-8-hydroxyquinoline (2), have been synthesized in high yields; the structures were confirmed by NMR, EPR, and IR spectroscopy, mass spectrometry, X-ray diffraction and elemental analysis. Depending on reaction conditions di-, tetra- or hexanuclear complexes 3–5 were obtained. It was demonstrated that in the presence of Et2AlCl/CCl3CO2Et, vanadium (V) complexes catalyzed polymerization of ethylene with activities up to 1000 kg of PE (mol of V)−1 h−1 atm−1.

A series of titanium complexes LTiCl2·(iPrOH)2 12-18 and heterobimetallic complex L2Ti·iPrOLi·THF 19 bearing saligenin-type [O,O]2- ligands 6-11 were synthesized in high yields from Cl2Ti(OiPr)2 or LiTi(OiPr)5. X-ray structure analyses for 15 and 19 revealed that these complexes adopt a distorted octahedron or distorted tetragonal pyramid geometry. When activated by binary activator {3Et2AlCl + Bu2Mg}, complexes 12-19 exhibited moderate to high activities toward ethylene and 1-hexene polymerization, giving high molecular weight polymers with broad molecular weight distributions. The results of this study show the unique ability of Li and Mg chlorides to improve the catalytic ability of post-metallocene pre-catalysts.

Novel titanium and zirconium alkoxo complexes bearing 6,6′-(piperazine-1,4-diyl)-bis-(2,4-di-tert-butylphenolate) ligand (L), LTi2(OiPr)6 (2) and L2Zr2(OBu)4 (3), has been synthesized in acceptable yields by the stoichiometric reaction of L with the respective M(OR)4. All complexes were fully characterized by elemental analysis and NMR spectroscopy, and the molecular structures of the representative complex 2 was confirmed as distorted trigonal bipyramid at titanium (coordination number 5) by single-crystal X-ray diffraction. Pre-catalysts 2–3 are active in ethylene and 1-hexene polymerization in the presence of Et2AlCl/Bu2Mg binary co-catalyst; but there were completely inactive in presence of MAO or Me3Al. Obtained polyethylene and polyhexene samples were of high molecular weight. The results of this study show the unique ability of Mg derivatives to improve the catalytic ability of post-metallocene pre-catalysts.

Copolymerization reactions of ethylene with three I±-olefins, 1-hexene, 1-octene and 1-decene, were carried out with a new post-metallocene catalyst based on Ti complex with a bidentate saligenin-type ligand I and two co catalysts, MAO and a combination of AlEt 2 Cl and MgBu 2 . Ability of the I - AlEt 2 Cl - MgBu 2 system to copolymerize I±-olefins with ethylene is far superior to that of the I - MAO system. Reactivity of I±-olefins in copolymerization reactions with ethylene decreases in the sequence: 1-hexene>1-octene>1-decene. Both catalyst systems, I - MAO and I - AlEt 2 Cl - MgBu 2 , contain several populations of active centers that greatly differs both in the average molecular weights and in composition of the copolymer molecules they produce. Active centers in both catalytic systems show significant tendency to alternate monomer units in copolymer chains.

A series of mono- and bi-nuclear complexes were synthesized by combining 2,6-bis-(α,α′-diphenyl(hydroxy)methyl)-pyridine and halide or alkoxide Ti(IV) derivatives. Crystal structures of synthesized products were determined. It was demonstrated that individual complexes 2–5 are active in ethylene and 1-hexene polymerization only in the presence of Et2AlCl/Bu2Mg binary co-catalyst. The systems formed from the lithium or magnesium salts of 2,6-bis(α,α′-diphenyl(hydroxy)methyl)-pyridine and TiCl4, containing respective Ti complexes and reaction byproducts (LiCl or MgCl2), are able to catalyze ethylene polymerization when activated by methylalumoxane or trimethylaluminum (TMA). The highest efficiency of catalysis was observed in the presence of binary co-catalysts Et2AlCl/Bu2Mg. The results of this study show the unique ability of Li and Mg chlorides to improve the catalytic ability of post-metallocene pre-catalysts.

Catalytic systems containing TiCl4 or TiCl3, THF, organomagnesium (n-Bu2Mg) and organoaluminum compounds capable of producing ultrahigh molecular weight polyethylene (UHMWPE) were developed. The resulting polymers were characterized by a molecular weight in the range of (1.8–7.8) × 106 Da and desirable morphology, suitable for modern methods of polymer processing—the solvent-free solid-state processing of superhigh-strength (tensile strength up to 2.1 GPa) and high-modulus (elastic modulus up to 125 GPa) oriented films and film tapes. The impacts of a THF additive, the oxidation state of the titanium atom, and the composition and nature of the nontransition organometallic compounds on the formation of catalytic systems for UHMWPE production were evaluated. The results indicate the suitability of individual titanium chloride tetrahydrofuran complex application for the formation of THF-containing catalytic systems. This approach also results in a significant increase in the system catalytic activity and mechanical properties of UHMWPE. The catalysts based on Ti(III) were inferior to systems containing Ti(IV) in productivity but were markedly superior in the mechanical properties of UHMWPE.

A series of titanium (IV) complexes 3a–g stabilized by fluorinated derivatives of 2-hydroxymethylphenol have been synthesized; their composition and structure have been confirmed by NMR, IR-spectroscopy and elemental analysis. The structures of compounds 3c, 3f and 3g have been unambiguously established by X-ray diffraction study. The complexes in the presence of a binary cocatalysts {alkyl aluminum chloride + MgBu2} catalyze ethylene polymerization to afford Ultra High Molecular Weight Polyethylene (UHMWPE). The effects of substituents in the ligands on the catalytic activity and properties of the obtained polymer – molecular weight, DSC melting behavior, and morphology of nascent reactor powders have been investigated. UHMWPE samples were processed by a solid-state uniaxial deformation into high-strength (up to 2.65 GPa) and high-modulus (over 140 GPa) oriented film tapes, which indirectly indicates a low degree of entanglements between the macromolecular chains.

Polymerization reactions of propylene and three higher linear 1-alkenes, 1-hexene, 1-octene and 1-decene, were carried out with post-metallocene catalysts derived from Ti complexes I and II with a bidentate phenol-alcohol (saligenin-type) ligand derived from 2,4-di- tert- butyl-6-(1,1,1,3,3,3-hexafluoro-2-hydroxy-propan-2-yl)phenol, in the presence of two cocatalysts, MAO and a combination of AlEt 2 Cl and MgBu 2 . All catalyst systems contain a large variety of active centers and produce both amorphous atactic polymers and partially crystalline isotactic material. The AlEt 2 Cl-MgBu 2 cocatalyst produces significantly more active catalyst systems. Analysis of 13 C NMR data for the propylene polymers shows that the mechanism of isotactic chain growth is principally different for the active centers formed in the presence of the two cocatalysts.

Coordination compounds of titanium (IV) and zirconium (IV) with tetra-aryl-1,3-dioxolan-4,5-dimethanol (1,2) derivatives were synthesized and characterized by NMR- and IR-spectroscopy and X-ray crystallography. It was demonstrated that titanium dichloride complexes (5–6, 9–12) when treated with MAO, TMA or TIBA are inactive in ethylene polymerization catalysis. However, these compounds become catalytically active in presence of lithium or magnesium chlorides. It was found that the magnitude of the resulting catalytic activity correlates with the following factors: mode of non-transition metals chlorides introduction to the reaction mixture, the nature of activator, and its overall amount. Resulting catalytic activity varied between 54 and 3500 kg PE/mole Ti٠h٠bar. Formed polymer was a linear polyethylene of high and ultrahigh molecular weight (over 5.95 105 g/mole) with high polydispersity index. Possible mechanisms of lithium and magnesium chlorides ability to promote the catalytic process were proposed.

Coordination compounds of chromium (III) and vanadium (III) and (V) with 2,6-bis(diphenylhydroxymethyl)pyridine have been synthesized. Composition and properties of the obtained complexes have been evaluated by NMR, IR spectroscopy, X-ray diffraction, and elemental analysis. Depending on the nature of the metal and the synthesis conditions, there are various types of coordination state of the terdentate pyridine ligand in the obtained complexes: it can bind either as a dianionic, bisalkoxide, terdentate (compounds 5, 7, 8, 9), monoanionic, alkoxide/alkohol, terdentate (compounds 4, 6) or as a neutral, bisalkohol, terdentate ligand (compound 3). Coordination compounds of chromium were found to be incapable of catalytic polymerization of ethylene. Catalytic activity of vanadium (III) and (V) complexes in this reaction varied between 85 and 578 kg PE/mol V h after activation with diethylaluminum chloride, depending on the V/Al ratio.

Effect of cocatalysts on the performance of three post-metallocene catalysts based on complexes I–III in Scheme 1 is studied by comparing their activity in the presence of two cocatalysts, MAO and a combination of AlEt2Cl and MgBu2, in propylene polymerization reactions. The second cocatalyst produces significantly more active catalysts. Analysis of GPC, DSC and 13C NMR data for the polymers suggests that the activity increase is caused by the formation of new types of active centers. Some of the new centers are isospecific and operate according to the enantiomorphic stereocontrol mechanism.