1421841-88-4

Upstream product

• 885-77-8 4,4'-dimethylbenzhydrol 
• 106-49-0 p-toluidine 

Downstream Products

• 1421841-89-5 N,N’-bis(2,6-bis(di-p-tolylmethyl)-4-methylphenyl)diazabutadiene 
• 1421841-85-1 1,3-bis(2,6-bis(di-p-tolylmethyl)-4-methylphenyl)imidazolium chloride 

Relevant academic research and scientific papers

Large-scale synthesis of novel sterically hindered acenaphthene-based α-diimine ligands and their application in coordination chemistry

An efficient method to synthesize novel highly sterically hindered acenaphthene-based α-diimine ligands bearing bulky diarylmethyl moiety was achieved by two-step reactions. These reactions could be carried out on a scale of 100 g with no chromatography involved. On the basis of this method, a series of novel highly sterically hindered acenaphthene-based α-diimine Pd(II) and Ni(II) complexes, imidazolium precursors and the corresponding NHCs-metal complexes were also successfully synthesized. These novel complexes can offer great potential for metal-catalyzed polymerizations and organic reactions.

Rotation-restricted strategy to synthesize high molecular weight polyethylene using iminopyridyl nickel and palladium catalyst

Most of the iminopyridyl Ni (II) and Pd (II) catalysts are reported to oligomerize ethylene or yield very low molecular weight polyethylene. Moreover, the molecular weight of product is not sensitive to ligand sterics. In this contribution, we demonstrate that the bulky rotation-restricted substituents incorporated into iminopyridyl Ni (II) and Pd (II) catalysts that provide the right orientation are highly effective in retarding the chain transfer. Thus, (2,6-bis(10,11-dihydro-5H-dibenzo[a,d][7]annulen-5-yl)-4-methylphenyl)-1-(pyridin-2-yl)methanimine nickel (II) bromide (Ni3) and (2,6-bis(10,11-dihydro-5H-dibenzo[a,d][7]annulen-5-yl)-4-methylphenyl)-1-(pyridin-2-yl)methanimine palladium (II) methyl chloride (Pd3) with the phenyl substituents fixed in the diarylmethyl moiety produce polyethylene or functionalized polyethylene (ethylene-MA copolymer) with high Mn values up to 2.5 × 104 g mol?1, while allowing the high MA incorporation (3.2%–13.8%). In addition, the effects on the (co)polymerization behavior as a function of rotation-restricted substituent variations (free rotation, restricted rotation and fixation) were systemically studied. As a result, various molecular weight polyethylene and ethylene-MA copolymer with high MA incorporation ratio were also obtained in this system.

Systematic Investigations of Ligand Steric Effects on α-Diimine Nickel Catalyzed Olefin Polymerization and Copolymerization

So far, ligand steric effects of the α-diimine nickel catalysts on the polyolefin branching densities are not systematically investigated. Generally, in contrast to the α-diimine palladium systems, the branching densities of the polyethylene obtained by the α-diimine nickel catalysts increased when the more sterically encumbering substituent was employed. In this contribution, we described the synthesis and characterization of a series of α-diimine ligands and the corresponding nickel catalysts bearing the diarylmethyl moiety and varied steric ligands. In ethylene polymerization, the catalytic activities [(2.82-15.68) × 106 g/(mol Ni·h)], polymer molecular weights [Mn: (0.37-131.51) × 104 g mol-1], branching densities [(28-81)/1000 C], and polymer melting temperatures (-4.7-122.9 °C) can be tuned over a very wide range. To our surprise, the polymer branching density first rose and then fell when we systematically increased the steric bulk of α-diimine nickel catalysts, like a downward parabola, not in line with previous conclusions. In ethylene-methyl 10-undecenoate (E-UA) copolymerization, the catalytic activities [(1.0 × 103) - (104.8 × 104) g/(mol Ni·h)], copolymer molecular weights [(1.2 × 103) - (242.4 × 103) g mol-1], branching densities [(42-70)/1000 C], and UA incorporation ratio (0.17-2.12%) can also be controlled over a very wide range. The tuning in steric ligands enables the tuning of the polymer microstructures such as molecular weight and branching density. In this way, the best polyethylene elastomer catalysts are screened out.

Distorted Sandwich α-Diimine PdII Catalyst: Linear Polyethylene and Synthesis of Ethylene/Acrylate Elastomers

The introduction of m-xylyl substituents to α-diimine PdII catalyst promotes living ethylene polymerization at room temperature and low pressure to yield high molecular weight polyethylene (PE) with low branching (a highly effective blockage to the axial sites of the catalytic center and form a distorted sandwich geometry. The shielding prevents chain-transfer and easy accessibility of polar monomers, leading to a living polymerization. Conducting a light irradiation as part of the one-step metal-organic insertion light initiated radical (MILRad) process leads to diblock copolymers of ethylene and acrylates. Incorporation of different acrylate block sequences can significantly modify the mechanical and chemical properties of block copolymers which can be modulated to be a hard plastic, elastomer, or semi-amorphous polymer.

Asymmetric alpha-diimine nickel (II) complex with ortho-position dimethyl benzyl substitution groups for vinyl polymerization

The invention belongs to the technical field of olefin polymerization, and particularly discloses an asymmetric alpha-diimine nickel (II) complex with ortho-position dimethyl benzyl substitution groups for vinyl polymerization. Large-steric-hindrance dimethyl benzyl groups are introduced to the aryl ortho position of the complex, the stability of a catalyst can be improved, the chain transfer process can be delayed, and polymers with high polymerization activity and high molecular weights can be generated. The 4'-position long-distance substitution group -CH3 of the dimethyl benzyl on an aromatic ring can more effectively partially block proceeding of chain transfer on the axial position than H substitution groups, and thus the molecular weight of produced polyvinyl is increased. Besides,by changing the steric hindrance and polymerization temperature of the complex, the catalytic activity and the physical and mechanical performance of the polymers can be effectively regulated and controlled.

[Pd(IPr*R)(acac)Cl]: Efficient bulky Pd-NHC catalyst for Buchwald-Hartwig C-N cross-coupling reaction

A series of bulky palladium catalysts based on N-heterocyclic carbene, (Pd(NHC)(acac)Cl: NHC = IPr*me = N,N′-bis(2,6-bis(di-p-tolylmethyl)-4-methylphenyl)-imidazol-2 -ylidene, Pd(IPr*me)(acac)Cl; NHC = IPr*ipr = N,N′-bis(2,6-bis(di-4-isopropylphenyl)-4-methylphenyl)-imidazol-2 -ylidene, Pd(IPr*ipr)(acac)Cl; and NHC = IPr*tBu = N,N′-bis(2,6-bis(di-4-(tert-butyl)phenyl)- 4-methylphenyl)- imidazol-2-ylidene, Pd(IPr*tBu)(acac)Cl; acac = acetylacetonate), have been designed and synthesized. These three new catalysts showed much better catalytic activity in the Buchwald?Hartwig arylamination coupling reaction as compare to the earlier congener (IPr*)Pd(acac)Cl (IPr* = N,N′-bis(2,6-diphenylmethyl)-4-methylphenylimidazol-2-ylidene). The highly active PdII precatalyst [Pd(IPr*me)(acac)Cl] has been fully explored by using a wide range of substrates with different electronic and steric demands of coupling partners, for which up to 99% isolated yields were obtained. Remarkably, the moderate isolated yield was obtained for the challenging coupling of the amine bearing very bulky groups.

Extending the utility of [Pd(NHC)(cinnamyl)Cl] precatalysts: Direct arylation of heterocycles

The use of [Pd(NHC)(cinnamyl)Cl] precatalysts in the direct arylation of heterocycles has been investigated. Among four different precatalysts, [Pd(SIPr)(cinnamyl)Cl] proved to be the most efficient promoter of the reaction. The C-H functionalization of sulfuror nitrogen-containing heterocycles has been achieved at low catalyst loadings. These catalyst charges range from 0.1 to 0.01 mol % palladium.