Ethylene oligomerization by diimine iron(II) complexes/EAO

The catalytic properties of a series of Fe(II) diimine complexes (diimine=N,N′-o-phenylenebis(salicylideneaminato), N,N′-ethylenebis(salicylideneaminato), N,N′-o-phenylenebisbenzal, N,N′-ethylenebisbenzal) in combination with ethylaluminoxane (EAO) for ethylene oligomerization have been investigated. Treatment of the iron(II) complexes with EAO in toluene generates active catalytic systems in situ that oligomerize ethylene to low-carbon olefins. The effects of reaction temperature, ratios of Al/Fe and reaction periods on catalytic activity and product distribution have been studied. The activity of complex FeCl₂(PhCH=o-NC₆H₄N=CHPh) with EAO at 200°C is 1.35×10⁵ g oligomers/mol Fe·h, and the selectivity of C_4–10 olefins is 84.8%.     

Ethylene Oligomerization Catalyzed by MCl2(PPh3)2 Complex‐es/Ethylaluminoxane

The catalytic properties of MCl₂ (PPh₃)₂ (M = Fe, A; Co, B; Ni, C) in combination with ethylaluminoxane (EAO) as cocatalyst for ethylene oligomerization have been investigated. Treatment of the MCl₂ (PPh₃)₂ complexes with EAO in toluene generated active catalysts in situ that are capable of oligomerizating ethylene to low‐carbon olefins. The catalytic activity and product distribution were affected by reaction condition, such as reaction temperature, the ratios of Al/M and the reaction time. The activity of 1.70 × 10⁵ g oligomers/ (mol Co. h) for the catalytic system of CoCl₂(PPh₃)₂ with EAO at 200°C was observed, with the selectivity of 91.1% to C_4–10 olefins and 70.7% to C_4–10 linear α‐olefins.     

Catalytic Effect of Cobalt and Iron Complexes Incorporating Bis(2-aldiminoethyl)amine Ligands on Ethylene Oligomerization

IntroductionThe finding of a new promising family ofFe( ) - and Co( ) - based bis( imino) pyridyl cata-lysts for ethylene polymerization and oligomeriza-tion,discovered by Brookhart,Gibson andcoworkers[1— 3 ] ,has intrigued us into researchingthe preparation,the structure and the chemistry ofiron and cobalt complexes incorporating N,N ,N -tridentate ligands.The spectacular enhancement ofthe reactivity of iron and cobalt complexes towardsZiegler- Natta olefin polymerization has been re-po…     

含有不同配体的钴配合物/EAO催化乙烯齐聚

考察了（bipy)CoCl2,(C6H5N=C-C6H4-o-O)2Co和（acac)2CO 3种配合物与EAO组成的二元催化体系A，B和C，在不同的反应温度，铝钴比以及不同反应时间对乙烯齐聚催化活性和选择性的影响，结果表明，3种催化体系都对催化乙烯齐聚反应有活性，在相同的反应条件下，3种催化体系对乙烯齐聚的催化活性顺序为：A＞B＞C，在反应温度为180摄氏度时，催化体系（bipy)CoCl2/EAO的活性为2441g/(gCo.H)，产物中低碳烯烃的选择性为95．9％。     

Ethylene Oligomerization Catalyzed by Nickel（Ⅱ） Diimine Complexes

Ethylene oligomerization has been investigated by using catalyst systems composed of nickel(II) diimine complexes (diimine = N, N′‐o‐phenylene bis (salicylideneaminato), N, N′‐o‐phenylenebisbenzal, N, N′‐ethylenebisbenzal) and ethylaluminoxane (EAO). The main products in toluene and at 110–200 °C were olefins with low carbon numbers (C₄—C₁₀). Effects of reaction temperature, Al/Ni molar ratio and reaction period on both the catalytic activity and product distribution were explored. The activity of 1.84 × 10⁵ g of oligomer/(mol_NI · h), with 87.4% of selectivity to C₄—C₁₀ olefins, was attained at 200 °C in the reaction when a catalyst composed of NiCl₂ (PhCH = o‐NC₆H₄N = CHPh) and EAO was used.     

Transition metal complexes bearing 2,6-bis(imino)pyridyl: Synthesis,structure, ethylene polymerization/ oligomerization studies

A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyridine}Cl₂ [M=Fe(II) (2), Co(II) (3), Ni(II) (4), Cu(II) (5), Zn(II) (6)] have been synthesized. At 25°C, using 500 equiv of methylaluminoxane (MAO), the activities of Fe(II), Co(II) catalysts can reach 4.02 ×10⁶ g/mol-Fehatm for ethylene polymerization and 3.98×10⁵ g/mol-Cohatm for ethylene oligomerization. The effects of polymerization conditions such as reaction temperature, Al/M molar ratio and time on the activity of catalyst have been explored.

     

Transition metal complexes bearing 2,6-bis(imino)pyridyl: Synthesis,structure, ethylene polymerization/ oligomerization studies

A series of new complexes {2,6-bis[1-((2-methyl-4-methoxyphenyl)imino)ethyl]pyridine}Cl₂ [M=Fe(II) (2), Co(II) (3), Ni(II) (4), Cu(II) (5), Zn(II) (6)] have been synthesized. At 25°C, using 500 equiv of methylaluminoxane (MAO), the activities of Fe(II), Co(II) catalysts can reach 4.02 ×10⁶ g/mol-Fehatm for ethylene polymerization and 3.98×10⁵ g/mol-Cohatm for ethylene oligomerization. The effects of polymerization conditions such as reaction temperature, Al/M molar ratio and time on the activity of catalyst have been explored.     

NNNO-Heteroscorpionate nickel (II) and cobalt (II) complexes for ethylene oligomerization: the unprecedented formation of odd carbon number olefins

The unprecedented observation of odd carbon number olefins is reported during nickel- catalyzed ethylene oligomerization. Two complexes based on Co (II) and Ni (II) with novel tetradentate heteroscorpionate ligand have been synthesized and fully characterized. These complexes showed the ability to oligomerize ethylene upon activation with various organoaluminum compounds (Et₂AlCl, Et₃Al₂Cl₃, EtAlCl₂, MMAO). Ni (II) based catalytic systems were sufficiently more active (up to 1900 kg·mol (Ni)⁻¹·h⁻¹·atm⁻¹) than Co (II) analogs and have been found to be strongly dependent on the activator composition. The use of PPh₃ as an additive to catalytic systems resulted in the increase of activity up to 4,150 kg·mol (Ni)⁻¹·h⁻¹·atm⁻¹ and in the alteration of selectivity. All Ni (II) based systems activated with EtAlCl₂ produce up to 5 mol. % of odd carbon number olefins; two probable mechanisms for their formation are suggested – metathesis and β-alkyl elimination.     

Hyperbranched macromolecules bridged salicylaldimine cobalt complexes: synthesis,characterization and ethylene oligomerization studies

A series of novel 1.0 generation (1.0G) hyperbranched macromolecules bridged salicylaldimine cobalt complexes were synthesized in high yields. The compounds were characterized by fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) visible spectroscopy, electrospray ionization mass spectrometry (ESI–MS), elemental analysis and thermal gravimetric analysis (TGA), as well as were investigated as precatalysts for the oligomerization of ethylene. Upon activation with methylaluminoxane (MAO) and diethylaluminumchloride (DEAC), the cobalt precatalysts showed moderate catalytic activities in the range of 10⁵ g/(mol Co h) in ethylene reactivity with the high selectivity for the butenes and high carbon number olefins products. The correlation between cobalt complexes and their catalytic activities and product distribution were investigated in detail under various reaction parameters. The research results showed that the catalytic activities of precatalysts increased with the increase of ethylene pressure and Al/Co molar ratio; however, the catalytic activities firstly increased and then decreased with the increase of reaction temperature. The highest activity of 2.54 × 10⁵ g/(mol Co h) and 50.18% selectivity of high number carbon olefins was obtained under the reaction temperature of 25 °C, ethylene pressure of 0.5 MPa, and Al/Co molar ratio of 1500. In addition, the nature of solvent and co-catalyst, as well as the structure of precatalysts, significantly affected both the activity and the product distribution of the resultant catalysts.     

Mono{hydrotris(mercaptoimidazolyl)borato} complexes of manganese(II), iron(II), cobalt(II), and nickel(II) halides

A series of [Tm(Me)M(mu-Cl)]2 and Tm(R)MCl (Tm(R) = tris(mercaptoimidazolyl)borate; R = Me, tBu, Ph, 2,6-iPr2C6H3 (Ar); M = Mn, Fe, Co, Ni) complexes have been prepared by treatment of NaTm(Me) or LiTm(R) with an excess amount of metal(II) chlorides, MCl2. Treatment of Tm(R)MCl (R = tBu, Ph, Ar) with NaI led to a halide exchange to afford Tm(R)MI. The molecular structures of [Tm(Me)M(mu-Cl)]2 (M = Mn, Ni), [Tm(Me)Ni(mu-Br)]2, Tm(tBu)MCl (M = Fe, Co), Tm(Ph)MCl (M = Mn, Fe, Co, Ni), Tm(Ar)MCl (M = Mn, Fe, Co, Ni), Tm(Ph)MI (M = Mn, Co), and Tm(Ar)MI (M = Fe, Co, Ni) have been determined by X-ray crystallography. The Tm(R) ligands occupy the tripodal coordination site of the metal ions, giving a square pyramidal or trigonal bipyramidal coordination geometry for Tm(Me)M(mu-Cl)]2 and a tetrahedral geometry for the Tm(R)MCl complexes, where the S-M-S bite angles are larger than the reported N-M-N angles of the corresponding hydrotris(pyrazolyl)borate (Tp(R)) complexes. Treatment of Tm(Ph)2Fe with excess FeCl2 affords Tm(Ph)FeCl, indicating that Tm(R)2M as well as Tm(R)MCl is formed at the initial stage of the reaction between MCl2 and the Tm(R) anion.     

Structural, spectroscopic and thermal characterization of 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester and its Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes

Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and UO(2)(II) complexes with the ligand 2-tert-butylaminomethylpyridine-6-carboxylic acid methylester (HL(2)) have been prepared and characterized by elemental analyses, molar conductance, magnetic moment, thermal analysis and spectral data. 1:1 M:HL(2) complexes, with the general formula [M(HL(2))X(2)].nH(2)O (where M = Co(II) (X = Cl, n = 0), Ni(II) (X = Cl, n = 3), Cu(II) (grey colour, X = AcO, n = 1), Cu(II) (yellow colour, X = Cl, n = 0) and Zn(II) (X = Br, n = 0). In addition, the Fe(III) and UO(2)(II) complexes of the type 1:2 M:HL(2) and with the formulae [Fe(L(2))(2)]Cl and [UO(2)(HL(2))(2)](NO(3))(2) are prepared. From the IR data, it is seen that HL(2) ligand behaves as a terdentate ligand coordinated to the metal ions via the pyridyl N, carboxylate O and protonated NH group; except the Fe(III) complex, it coordinates via the deprotonated NH group. This is supported by the molar conductance data, which show that all the complexes are non-electrolytes, while the Fe(III) and UO(2)(II) complexes are 1:1 electrolytes. IR and H1-NMR spectral studies suggest a similar behaviour of the Zn(II) complex in solid and solution states. From the solid reflectance spectral data and magnetic moment measurements, the complexes have a trigonal bipyramidal (Co(II), Ni(II), Cu(II) and Zn(II) complexes) and octahedral (Fe(III), UO(2)(II) complexes) geometrical structures. The thermal behaviour of the complexes is studied and the different dynamic parameters are calculated applying Coats-Redfern equation.     

Syntheses,characterization, in vitro antiglycation and DPPH radical scavenging activities of isatin salicylhydrazidehydrazone and its Mn (II), Co (II), Ni (II), Cu (II), and Zn (II) metal complexes

2-Hydroxy salicylhydrazide isatin hydrazone (L) and its Mn (II), Co (II), Ni (II), Cu (II), and Zn (II), metal complexes were synthesized. ¹H NMR, UV–Vis, IR spectroscopy and elemental (CHN/S) analysis techniques were applied for characterization. TG/DTA techniques revealed that all the synthetic compounds are thermally stable up to 300 °C. They were found non-electrolytes in nature. Furthermore, all these complexes were evaluated for antiglycation and DPPH radical scavenging activities. They showed varying degree of activity with IC₅₀ values between 168.23 and 269.0 μM in antiglycation and 29.63–57.71 μM in DPPH radical scavenging activity. Mn (II), Co (II), Ni (II), Cu (II), and Zn (II), metal complexes showed good antiglycation as well as DPPH radical scavenging activity. The IC₅₀ values for antiglycation activity are 168.23 ± 2.37, 234.27 ± 4.33, 257.1 ± 6.43, 267.7 ± 8.43, 269.0 ± 8.56 Ni for Co, Zn, Mn, Cu, and Ni complexes, respectively, while IC₅₀ value were found to be 29.63 ± 2.76, 31.13 ± 1.41, 35.16 ± 2.45, 43.53 ± 3.12, 57.71 ± 2.61 μM for Cu, Zn, Mn, Co and Ni complexes, respectively, for DPPH radical scavenging activity. These synthesized metal complexes were found to be better active than standards Rutin (IC₅₀ = 294.46 μM) for anti-glycation, and tert-butyl-4-hydroxyanisole (IC₅₀ = 44.7 μM) for DPPH radical scavenging activity.     

Transition metal polymeric chelates: Spectral, magnetic, thermal behaviour of polymeric chelates of poly(resacetophenone diyl ethylene)s with Ni(II), Cu(II), Mn(II), Zn(II) and Co(II)

Polymeric chelates of the type [ML₂]_n where M = Ni(II), Cu(II), Zn(II) or Co(II), L = poly(resacetophenone diyl ethylene)s, andn= degree of polymerization, have been synthesized. Their structures have been elucidated on the basis of analytical, magnetic, electronic and IR spectral studies. Electronic spectra in conjunction with magnetic moments are in accord with an octahedral environment around the central metal ion in all polymeric chelates except Cu(II) and Zn(II) polymeric chelates which have been shown to possess square planar and tetrahedral geometries, respectively. IR spectral studies further suggest that the metal ions are coordinated through the oxygens of the carbonyl and the phenolic hydroxyl groups. All the chelates are paramagnetic except Zn(II), which is found to be diamagnetic.     

Potentiometric study of the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with 3-hydroxy-2-naphthalene carboxylic acid

Formation constants of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with 3-hydroxy-2-naphthalene carboxylic acid have been determined potentiometrically in a 50% (v/v) dioxane—water solution at 25°C and 0.2 M KNO₃. Experimental data are analysed using several computer programs. The obtained values for the log of the formation constant of the first 1 : 1 (metal : ligand) complex with the different metals are: Co 7.9, Ni 7.1, Cu 10.44, Zn 7.8 and Cd 7.3. The log of the formation constant for the 1 : 2 copper complex is 18.20. It is to be noted that Ni(II) yields a 1 : 1 complex weaker than expected from the Irving—Williams series.     

N-vinylcarbazole polymerization by 13X molecular sieve exchanged with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)

The polymerization of N-vinylcarbazole by 13X molecular sieves modified by five different transition metal ions, viz. Mn(II), Co(II), Ni(II), Cu(II) and Zn(II), has been studied under various conditions. The order of reactivity follows the trend: Mn(II) ≈ Cu(II) > Co(II) > Zn(II) > Ni(II) at pH ∼ 3.55 and an exchange level of 30% of the metal ion. The polymerizations are believed to occur by a dual-ion-initiation mechanism in which both metal ions and proton centres participate. The overall energy of activation (E_a) for each system decreases with decreasing pH of the exchanging salt solution. Average activation energy on proton centre (E_H) and that on metal ion centre (E_a) have been evaluated for each system. E_a, E_H and E_c have been shown to correlate with one another. The molecular weights and their distributions are affected by the nature of the metal ion and also by the protonic centres. The possibility of a correlation of the catalytic activity of the modified 13X with ionic radius, electronegativity and normal co-ordination number has been examined.     

Synthesis of iron(II), manganese(II) cobalt(II) and ruthenium(II) complexes containing tridentate nitrogen ligands and their application in the catalytic oxidation of alkanes

A series of Fe(II), Mn(II), Co(II) and Ru(II) complexes containing bis(imino)pyridine or bis(amino)pyridine ligands and weakly coordinating triflate (OTf-) or non-coordinating SbF6- anions have been prepared. The complexes have been fully characterized including several solid-state structure analyses. Two unusual mono-chelate six-coordinate bis(imino)pyridine Fe(II) and Mn(II) complexes have been observed. The catalytic properties of the complexes for the oxidation of cyclohexane with H2O2 have been evaluated. Only the Fe(II) complexes have shown catalytic activity, which is mainly due to Fenton-type free radical auto-oxidation.     

Organic acid solutions in the chromatography of inorganic ions. VII. Cation exchange of Mg(II), Ca(II), Sr(II), Ba(II), Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II) and Fe(III) in succinate media

Summary The cation-exchange behaviour of Mg(II), Ca(II), Sr(II), Ba(II), Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II) and Fe(III) in succinate media at various concentrations and pH, was studied with Dowex 50 WX8 resin (200–400 mesh) in the NH ₄ ⁺ form. As examples separations of Cd(II)/Co(II), Cd (II)/Ni(II), Fe(III)/Cu(II)/Ni(II) and Mg(II)/Ca(II)/Sr(II)/Ba(II) have been achieved.This work was supported by C.N.R. of Italy.     

M(C6H16N3)2(VO3)4 as heterogeneous catalysts. Study of three new hybrid vanadates of cobalt(II), nickel(II) and copper(II) with 1-(2-aminoethyl)piperazonium

Three new hybrid vanadates have been synthesized under hydrothermal conditions with the formula M(C(6)H(16)N(3))(2)(VO(3))(4), where M = Co(II), Ni(II) and Cu(II). The structural analyses show that the phases are isostructural and crystallize in the monoclinic space group P2(1)/c. These compounds show a two-dimensional crystal structure, with sheets composed of [VO(3)](n)(n-) chains and metal centres octahedrally coordinated, chelated by two 1-(2-aminoethyl)piperazonium ligands. The thermal study reveals that the copper containing phase is less stable than the cobalt and nickel containing ones. The IR spectra of the three phases are very similar, with little differences in the inorganic bond region of the copper containing phase. The UV-visible spectra show that the cobalt(II) and the nickel(II) are in slightly distorted octahedral environments. The catalytic tests show that the phases act as heterogeneous catalysts for the selective oxidation of alkyl aryl sulfides, with both H(2)O(2) and tert-butylhydroperoxide as oxidizing agents. The influence of the steric hindrance in the kinetic profile has been studied. The catalytic reactions induce the partial amorphization of the phases.     

Preparation, characterization and biological activity of Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) complexes of new cyclodiphosph(V)azane of sulfaguanidine

Novel hexachlorocyclodiphosph(V)azane of sulfaguanidine, H(4)L, l,3-[N'-amidino-sulfanilamide]-2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane was prepared and its coordination behaviour towards the transition metal ions Fe(III), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and UO(2)(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV-vis, (1)H NMR, mass spectra, reflectance, magnetic susceptibility measurements and thermogravimetric analysis (TGA). The hyperfine interactions in the isolated complex compounds were studied using 14.4keV gamma-ray from radioactive (57)Co (M?ssbauer spectroscopy). The data show that the ligand are coordinated to the metal ions via the sulfonamide O and deprotonated NH atoms in an octahedral manner. The H(4)L ligand forms complexes of the general formulae [(MX(z))(2)(H(2)L)H(2)O)(n)] and [(FeSO(4))(2) (H(4)L) (H(2)O)(4)], where X=NO(3) in case of UO(2)(II) and Cl in case of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II). The molar conductance data show that the complexes are non-electrolytes. The thermal behaviour of the complexes was studied and different thermodynamic parameters were calculated using Coats-Redfern method. Most of the prepared complexes showed high bactericidal activity and some of the complexes show more activity compared with the ligand and standards.     

Preparation and characterization of Cr(III), Mn(II), Fe(II), Co(II) and Ni(II) complexes of a hexaazadithiophenolate macrocycle

The ligating properties of the 24-membered macrocyclic dinucleating hexaazadithiophenolate ligand (L(Me))2- towards the transition metal ions Cr(II), Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) have been examined. It is demonstrated that this ligand forms an isostructural series of bioctahedral [(L(Me))M(II)2(OAc)]+ complexes with Mn(II) (2), Fe(II) (3), Co(II) (4), Ni(II) (5) and Zn(II) (6). The reaction of (L(Me))2- with two equivalents of CrCl2 and NaOAc followed by air-oxidation produced the complex [(L(Me))Cr(III)H2(OAc)]2+ (1), which is the first example for a mononuclear complex of (L(Me))2-. Complexes 2-6 contain a central N3M(II)(mu-SR)2(mu-OAc)M(II)N3 core with an exogenous acetate bridge. The Cr(III) ion in is bonded to three N and two S atoms of (L(Me))2- and an O atom of a monodentate acetate coligand. In 2-6 there is a consistent decrease in the deviations of the bond angles from the ideal octahedral values such that the coordination polyhedra in the dinickel complex 5 are more regular than in the dimanganese compound 2. The temperature dependent magnetic susceptibility measurements reveal the magnetic exchange interactions in the [(L(Me))M(II)2(OAc)]+ cations to be relatively weak. Intramolecular antiferromagnetic exchange interactions are present in the Mn(II)2, Fe(II)2 and Co(II)2 complexes where J = -5.1, -10.6 and approximately -2.0 cm(-1) (H = -2JS1S2). In contrast, in the dinickel complex 5 a ferromagnetic exchange interaction is present with J = +6.4 cm(-1). An explanation for this difference is qualitatively discussed in terms of the bonding differences.