scholarly journals Highly Linear Polyethylenes Achieved Using Thermo-Stable and Efficient Cobalt Precatalysts Bearing Carbocyclic-Fused NNN-Pincer Ligand

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1176 ◽  
Author(s):  
Jingjing Guo ◽  
Zheng Wang ◽  
Wenjuan Zhang ◽  
Ivan Oleynik ◽  
Arumugam Vignesh ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
13C Nmr Spectroscopy ◽  
Active Species ◽  
Direct Reaction ◽  
Chloride Complexes ◽  
Linear Polyethylene ◽  
Pyramidal Geometry ◽  
Ft Ir ◽  
The One ◽  
Thermo Stability

Six examples of 2-(1-arylimino)ethyl-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridine-cobalt(II) chloride complexes, [2-(1-ArN)C2H3-9-ArN-5,6,7,8-C5H8C5H3N]CoCl2, (Ar = 2-(C5H9)-6-MeC6H3 Co1, 2-(C6H11)-6-MeC6H3 Co2, 2-(C8H15)-6-MeC6H3 Co3, 2-(C5H9)-4,6-Me2C6H2 Co4, 2-(C6H11)-4,6-Me2C6H2 Co5, and 2-(C8H15)-4,6-Me2C6H2 Co6), were synthesized by the direct reaction of the corresponding ortho-cycloalkyl substituted carbocyclic-fused bis(arylimino)pyridines (L1–L6) and cobalt(II) chloride in ethanol with good yields. All the synthesized ligands (L1–L6) and their corresponding cobalt complexes (Co1–Co6) were fully characterized by FT-IR, 1H/13C-NMR spectroscopy and elemental analysis. The crystal structure of Co2 and Co3 revealed that the ring puckering of both the ortho-cyclohexyl/cyclooctyl substituents and the one pyridine-fused seven-membered ring; a square-based pyramidal geometry is conferred around the metal center. On treatment with either methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), all the six complexes showed high activities (up to 4.09 × 106 g of PE mol−1 (Co) h−1) toward ethylene polymerization at temperatures between 20 °C and 70 °C with the catalytic activities correlating with the type of ortho-cycloalkyl substituent: Cyclopentyl (Co1 and Co4) > cyclohexyl (Co2 and Co5) > cyclooctyl (Co3 and Co6) for either R = H or Me and afforded strictly linear polyethylene (Tm > 130 °C). The narrow unimodal distributions of the resulting polymers are consistent with single-site active species for the precatalyst. Furthermore, compared to the previously reported cobalt analogues, the titled precatalysts exhibited good thermo-stability (up to 70 °C) and possessed longer lifetime along with a higher molecular weight of PE (Mw: 9.2~25.3 kg mol−1).

scholarly journals Fusing Carbocycles of Inequivalent Ring Size to a Bis(imino)pyridine-Iron Ethylene Polymerization Catalyst: Distinctive Effects on Activity, PE Molecular Weight, and Dispersity

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Zheng Wang ◽  
Gregory A. Solan ◽  
Yanping Ma ◽  
Qingbin Liu ◽  
Tongling Liang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Ethylene Polymerization ◽  
Bimodal Distribution ◽  
X Ray Diffraction ◽  
One Pot ◽  
Molecular Weights ◽  
Pyramidal Geometry ◽  
Wide Range ◽  
Saturated Chain ◽  
Ft Ir

The 4,6-bis(arylimino)-1,2,3,7,8,9,10-heptahydrocyclohepta[b]quinoline-iron(II) chlorides (aryl = 2,6-Me2C6H3Fe1; 2,6-Et2C6H3Fe2; 2,6-i-Pr2C6H3Fe3; 2,4,6-Me3C6H2Fe4; and 2,6-Et2-4-Me2C6H2Fe5) have been prepared in good yield by a straightforward one-pot reaction of 2,3,7,8,9,10-hexahydro-1H-cyclohepta[b]quinoline-4,6-dione, FeCl2·4H2O, and the appropriate aniline in acetic acid. All ferrous complexes have been characterized by elemental analysis and FT-IR spectroscopy. In addition, the structure of Fe3 has been determined by single crystal X-ray diffraction, which showed the iron center to adopt a distorted square pyramidal geometry with the saturated sections of the fused six- and seven-membered carbocycles to be cis-configured. In combination with either MAO or MMAO, Fe1–Fe5 exhibited exceptionally high activities for ethylene polymerization (up to 15.86×106 gPE mol−1 Fe h−1 at 40°C (MMAO) and 9.60×106 gPE mol−1 Fe h−1 at 60°C (MAO)) and produced highly linear polyethylene (HLPE, Tm≥128°C) with a wide range in molecular weights; in general, the MMAO-promoted polymerizations were more active. Irrespective of the cocatalyst employed, the 2,6-Me2-substituted Fe1 and Fe4 proved the most active while the more sterically hindered 2,6-i-Pr2Fe3 the least but afforded the highest molecular weight polyethylene (Mw: 65.6–72.6 kg mol-1). Multinuclear NMR spectroscopic analysis of the polymer formed using Fe4/MMAO at 40°C showed a preference for fully saturated chain ends with a broad bimodal distribution a feature of the GPC trace (Mw/Mn=13.4). By contrast, using Fe4/MAO at 60°C a vinyl-terminated polymer of lower molecular weight (Mw=14.2 kg mol−1) was identified that exhibited a unimodal distribution (Mw/Mn=3.8). Moreover, the amount of aluminoxane cocatalyst employed, temperature, and run time were also found to be influential on the modality of the polymer.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

scholarly journals Clean one-pot multicomponent synthesis of pyrans using a green and magnetically recyclable heterogeneous nanocatalyst

SynOpen ◽  
2021 ◽  
Author(s):  
Mina Ghassemi ◽  
Ali Maleki
Keyword(s):  
Room Temperature ◽  
Significant Loss ◽  
Copper Ferrite ◽  
Multicomponent Synthesis ◽  
Thermo Gravimetric ◽  
Sem Images ◽  
One Pot ◽  
Three Component Reaction ◽  
Ft Ir ◽  
The One

Copper ferrite (CuFe2O4) magnetic nanoparticles (MNPs) were synthesized via thermal decomposition method and applied as a reusable and green catalyst in the synthesis of functionalized 4H-pyran derivatives using malononitrile, an aromatic aldehyde and a β-ketoester in ethanol at room temperature. Then it was characterized by Fourier transform infrared spectroscopy (FT-IR), energy-dispersive X-ray spectroscopy (EDX) analysis, scanning electron microscopy (SEM) images, thermo gravimetric and differential thermo gravimetric (TGA/DTG) analysis. The catalyst was recovered from the reaction mixture by applying an external magnet and decanting the mixture. Recycled catalyst was reused for several times without significant loss in its activity. Running the one-pot three-component reaction at room temperature, no use of eternal energy source and using a green solvent provide benign, mild, and environmentally friendly reaction conditions; as well, ease of catalyst recovering, catalyst recyclability, no use of column chromatography and good to excellent yields are extra advantages of this work.

scholarly journals A New Supported Manganese-Based Coordination Complex as a Nano-Catalyst for the Synthesis of Indazolophthalazinetriones and Investigation of Its Antibacterial Activity

Chemistry ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 783-799
Author(s):  
Maryam Ariannezhad ◽  
Davood Habibi ◽  
Somayyeh Heydari ◽  
Vahideh Khorramabadi
Keyword(s):  
Antibacterial Activity ◽  
Simple Procedure ◽  
Condensation Reaction ◽  
Antibacterial Properties ◽  
Coordination Complex ◽  
Bacterial Strains ◽  
One Pot ◽  
Nano Catalyst ◽  
Ft Ir ◽  
The One

A new magnetic supported manganese-based coordination complex (Fe3O4@SiO2@CPTMS@MBOL@ Mn) was prepared in consecutive stages and characterized via various techniques (VSM, SEM, TEM, XRD, FT-IR, EDX, TG-DTA, and ICP). To evaluate its application, it was used for synthesis of divers Indazolophthalazinetriones in a simple procedure via the one-pot three-component condensation reaction of aldehydes, dimedone, and phthalhydrazide in ethanol under reflux conditions. The Mn catalyst can be recycled without any noticeable loss in catalytic activity. Additionally, the antibacterial properties of the nano-catalyst were studied against some bacterial strains.

2-(1-(Arylimino)ethyl)-8-arylimino-5,6,7-trihydroquinoline Iron(II) Chloride Complexes: Synthesis, Characterization, and Ethylene Polymerization Behavior

2012 ◽  
Vol 31 (14) ◽  
pp. 5039-5048 ◽  
Author(s):  
Wenjuan Zhang ◽  
Wenbin Chai ◽  
Wen-Hua Sun ◽  
Xinquan Hu ◽  
Carl Redshaw ◽  
...  
Keyword(s):  
Ethylene Polymerization ◽  
Chloride Complexes ◽  
Polymerization Behavior

Cobalt(II) chloride adducts with acetonitrile, propan-2-ol and tetrahydrofuran: considerations on nuclearity, reactivity and synthetic applications

2017 ◽  
Vol 73 (2) ◽  
pp. 104-114 ◽  
Author(s):  
Danilo Stinghen ◽  
André Luis Rüdiger ◽  
Siddhartha O. K. Giese ◽  
Giovana G. Nunes ◽  
Jaísa F. Soares ◽  
...  
Keyword(s):  
Single Molecule ◽  
Building Blocks ◽  
Direct Reaction ◽  
X Ray Diffraction ◽  
Single Molecule Magnets ◽  
X Ray ◽  
Ft Ir ◽  
Bond Network ◽  
Solvent Molecules ◽  
Intramolecular Hydrogen

High-spin cobalt(II) complexes are considered useful building blocks for the synthesis of single-molecule magnets (SMM) because of their intrinsic magnetic anisotropy. In this work, three new cobalt(II) chloride adducts with labile ligands have been synthesized from anhydrous CoCl2, to be subsequently employed as starting materials for heterobimetallic compounds. The products were characterized by elemental, spectroscopic (EPR and FT–IR) and single-crystal X-ray diffraction analyses.trans-Tetrakis(acetonitrile-κN)bis(tetrahydrofuran-κO)cobalt(II) bis[(acetonitrile-κN)trichloridocobaltate(II)], [Co(C2H3N)4(C4H8O)2][CoCl3(C2H3N)]2, (1), comprises mononuclear ions and contains both acetonitrile and tetrahydrofuran (thf) ligands, The coordination polymercatena-poly[[tetrakis(propan-2-ol-κO)cobalt(II)]-μ-chlorido-[dichloridocobalt(II)]-μ-chlorido], [Co2Cl4(C3H8O)4], (2′), was prepared by direct reaction between anhydrous CoCl2and propan-2-ol in an attempt to rationalize the formation of the CoCl2–alcohol adduct (2), probably CoCl2(HOiPr)m. The binuclear complex di-μ-chlorido-1:2κ4Cl:Cl-dichlorido-2κ2Cl-tetrakis(tetrahydrofuran-1κO)dicobalt(II), [Co2Cl4(C4H8O)4], (3), was obtained from (2) after recrystallization from tetrahydrofuran. All three products present cobalt(II) centres in both octahedral and tetrahedral environments, the former usually less distorted than the latter, regardless of the nature of the neutral ligand. Product (2′) is stabilized by an intramolecular hydrogen-bond network that appears to favour atransarrangement of the chloride ligands in the octahedral moiety; this differs from thecisdisposition found in (3). The expected easy displacement of the bound solvent molecules from the metal coordination sphere makes the three compounds good candidates for suitable starting materials in a number of synthetic applications.

Ethylene polymerization on a SiH4-modified Phillips catalyst: detection of in situ produced α-olefins by operando FT-IR spectroscopy

2012 ◽  
Vol 14 (7) ◽  
pp. 2239 ◽  
Author(s):  
Caterina Barzan ◽  
Elena Groppo ◽  
Elsje Alessandra Quadrelli ◽  
Vincent Monteil ◽  
Silvia Bordiga
Keyword(s):  
Ir Spectroscopy ◽  
Ethylene Polymerization ◽  
Phillips Catalyst ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Remote dibenzocycloheptyl substitution on a bis(arylimino)pyridyl-iron ethylene polymerization catalyst; enhanced thermal stability and unexpected effects on polymer properties

2021 ◽  
Author(s):  
Liwei Guo ◽  
Wenjuan Zhang ◽  
Furong Cao ◽  
Youshu Jiang ◽  
Randi Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ethylene Polymerization ◽  
Chloride Complexes ◽  
Polymerization Catalyst ◽  
Polymer Properties

Four examples of para-dibenzocycloheptyl-substituted 2,6-bis(arylimino)pyridyl-iron(II) chloride complexes, [2,6-{(2-R1,4-(C15H13),6-R2C6H2)N=CMe}2C5H3N]FeCl2 (R1 = R2 = Me Fe1, Et Fe2, iPr Fe3, R1 = Me, R2 = Et Fe4), have been synthesized and characterized...

Synthethic pathways to multiple surface functionalization of polyhedral boranes

2019 ◽  
Author(s):  
◽  
Teng-Wei Wang
Keyword(s):  
High Resolution Mass Spectrometry ◽  
Molar Absorptivity ◽  
Quantum Yields ◽  
Direct Reaction ◽  
Close Monitoring ◽  
Fluorescence Excitation ◽  
University Of Missouri ◽  
Product Ions ◽  
Ft Ir ◽  
The University

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The chemistry of dodecahydro--closo--dodecaborate(2-), closo-[B12H12]2-, and decahydro-closo-decaborate(2-), [B10H10]2-, with different organic substituents was investigated in this research. The previously reported sequential synthesis of closo-[B12H12]2- hydroxyl derivatives were irreproducible. Through close monitoring of time and temperature mono-, di-, and tri- substituted hydroxyl, [B12H12-y(OH)y]2-, was synthesized in a controlled manner at 0.5 g, 5 g, and 10 g scales with significantly improved yields, >86%, 68%, >95%, respectively. Each of the hydroxylated species were exhaustively chlorinated in yields exceeding 95%. Oxidizing the perchlorinated hydroxylated products to the neutral species allows for their solubility in organic solvents, thus, open to easier manipulation in various organic settings and more accessible to perform organic chemistry. The more organic behavior of the cage allows us to synthesize hydroxyl derivatives. closo-[B12H10(SH)2]2- was synthesized from reduction of the inner-sulfonium salt of closo-[B12H10(SMe2)2] to make a suitable candidate for single molecular electronic conductors. An alternative synthetic route was proposed using ethylenediamine and n-propylamine as a great substitute for methylamine in the reaction for the formation of dithiol derivative from 1. A yield of 70% - 75% of the bis-(1,12-thiol)-closo-dodecaborate(2-) and 75% - 83% of bis-(1,7-thiol)-closo-dodecaborate(2-) was reported using this method. Recently, we reported a new class of organic-inorganic hybrid nanomolecular ions designated as polyarylboranes. These polyarylboranes are synthesized from the direct reaction between closo-[B12H12]2-or closo-[B10H10]2- and various aromatic hydrocarbons. The highly fluorescent characteristics of the product ions in solution results in high fluorescent quantum yields (0.3 to 0.6), high molar absorptivity, and large Stokes shifts (>200 nm). All of the newly synthesized compounds have been characterized by FT-IR, multi-nuclei NMR, and high-resolution mass spectrometry. In addition, the absorption, fluorescence excitation and emission properties for many of these materials have been measured.

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