84995-12-0

Upstream product

• 37942-07-7 3,5-di-tert-butyl-2-hydroxybenzaldehyde 
• 35132-20-8 (R,R)-1,2-diphenylethylenediamine 
• 96-76-4 2,4-di-tert-Butylphenol 
• 1073145-36-4 C₁₄H₁₆N₂*C₄H₆O₆ 
• 5700-60-7 1,2-Diphenylethylenediamine 

Relevant academic research and scientific papers

A non-metal Acen-H catalyst for the chemical fixation of CO2 into cyclic carbonates under solvent- and halide-free mild reaction conditions

A metal-free Acen-H catalyst was effectively synthesized by a single step reflux method and successfully tested for the cycloaddition of CO2 with epoxides to synthesize cyclic carbonates. The Acen-H catalyst exhibited high activity and selectivity for the cycloaddition reaction in the absence of co-catalysts (halides) and solvents at mild reaction conditions of a reaction temperature of 110 °C and a reaction pressure of 1 MPa. Under the optimized reaction conditions, some of the epoxides were successfully converted into corresponding cyclic carbonates with a highest yield of ～98.5%. The composition and structure of the homogeneous catalyst was then systematically evaluated and the reaction kinetics and a plausible reaction mechanism for the cycloaddition of CO2 with epoxides were proposed. The density functional theory (DFT) calculation provided a corroborated elucidation for the proposed mechanism. The catalytic activity of the Acen-H catalyst was found to be originated from the active hydrogen bond donors (-O-H, =N---H) and imino groups present (-N=) in it, which played a synergistic role in the adsorption and activation of reactants as confirmed by the DFT studies. The structural characteristics of the catalyst was found to be crucial for the cycloaddition of CO2 with epoxides.

Chiral Zn-salen complexes: a new class of fluorescent receptors for enantiodiscrimination of chiral amines

The first example of fluorescent chiral Zn-salen hosts, able to efficiently recognise chiral amines via non-covalent interactions, is reported here. The host-guest interactions have been characterised by 2D-NMR spectroscopy in order to elucidate the origi

Cobalt(II)[salen]-Catalyzed Selective Aerobic Oxidative Cross-Coupling between Electron-Rich Phenols and 2-Naphthols

A selectivity-driven catalyst design approach was adopted to address chemoselectivity issues in the oxidative coupling of phenols. This approach was utilized for developing a Co(II)[salen]-catalyzed aerobic oxidative cross-coupling of phenols in a recyclable 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) solvent. The waste-free conditions offer a sustainable entry to nonsymmetric biphenols via a mechanistic scheme that involves coupling of a liberated phenoxyl radical with a ligated 2-naphthoxyl radical.

Chiral (1,2)-diphenylethylene-salen complexes of triel metals: Coordination patterns and mechanistic considerations in the isoselective ROP of lactide

The synthesis of enantiomerically pure aluminium, gallium and indium complexes supported by chiral (R,R)-(HHONNOHH) (1), (R,R)-(MeHONNOHMe) (2), (R,R)-(tButBuONNO tButBu) (3), (R,R)-(MeNO2ONNOMeNO2) (4), (R,R)-(HOMeONNOHOMe) (5) and (R,R)-( ClClONNOClCl) (6) (1,2)-diphenylethylene-salen ligands is described. Several of these complexes have been crystallographically authenticated, which highlights a diversity of coordination patterns. Whereas all Ga complexes form [Ga2(CH2SiMe3) 4(ONNO)] bimetallic species (ONNO=1-3), aluminium [AlR(ONNO)] (R=Me, CH2SiMe3) and indium [In(CH2SiMe 3)(ONNO)] derivatives are monometallic for ONNO=1, 2 and 4-6, and only form the bimetallic complexes [Al2R4(ONNO)] and [In2(CH2SiMe3)4(ONNO)] for the most sterically crowded ligand 3. The [AlMe(ONNO)] complexes react with iPrOH to give [AlOiPr(ONNO)] complexes that are robust towards further iPrOH. The [In(CH 2SiMe3)(ONNO)] congeners are inert towards excess alcohol, whereas the Ga compounds decompose easily. All these alkyl complexes, as well as the [AlOiPr(ONNO)] derivatives, catalyse the ring-opening polymerisation (ROP) of racemic lactide (rac-LA). The [AlMe(ONNO)] complexes require additional alcohol to afford controlled reactions, but [AlOiPr(ONNO)] complexes are single-component catalysts for the isoselective ROP of rac-LA, with values of Pm in the range 0.80-0.90. Experimental evidence unexpectedly shows that chain-end control leads to the isoselectivity of these aluminium catalysts; also, the more crowded the coordination sphere, the higher the isoselectivity. The bimetallic Ga complexes do not afford controlled reactions, but the binary [In(ONNO)(CH2SiMe3)/(PhCH2OH)] systems competently mediate non-stereoselective ROP; evidence is given that an activated monomer mechanism is at work. Kinetic studies show that catalytic activity decreases when electronic density and steric congestion at the metal atom increase. Class act: A new range of monometallic chiral salen-aluminium complexes based on a less-classical chiral backbone has been developed. These constitute efficient precatalysts for the isoselective ring-opening polymerisation of racemic lactide. According to chain-end control, they afford poly(lactide) (PLA) featuring high isotacticity (Pm≈0.80-0.90) in the upper range reported to date (see figure).

Dual catalyst system for asymmetric alternating copolymerization of carbon dioxide and cyclohexene oxide with chiral aluminum complexes: Lewis base as catalyst activator and lewis acid as monomer activator

Optically active aluminum complexes such as Schiff base, binuclear β-ketoiminate, and bisprolinol complexes were found to promote asymmetric alternating copolymerizations of carbon dioxide and cyclohexene oxide. The aluminum Schiff base complexes-tetraethylammonium acetate afforded isotactic poly(cyclohexene carbonate)s with low enantioselectivities. Lewis bases having two coordinating sites were utilized to enhance activity and selectivity based on the binuclear structure of the aluminum β-ketoiminate clarified by X-ray crystallography. [2gAlMe]2-bulky bisimidazole produced the alternating copolymer with high enantioselectivity (62% ee). The polymerization is considered to preferentially proceed at more crowded, enantioselective site owing to coordination of bulky Lewis bases to aluminums in less enantioselective sites. 32AlMe-2-picoline also exhibited a high enantioselectivity (67% ee). Methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) was applied to perform faster and more enantioselective copolymerizations at low temperature (82% ee). The asymmetric copolymerizations were found to be significantly dependent on size of epoxide, temperature, and kind/amount of activators.

Titanium(IV)(salen) and yanadium(V)(salen) complexes derived from C 2- and C1-symmetric diamines for asymmetric cyanohydrin synthesis

Titanium and vanadium salen complexes have been prepared from C 2- and C1-symmetric acyclic diamines. All of the complexes catalysed the asymmetric addition of trimethylsilyl cyanide to benzaldehyde and the sense of asymmetric induction was determined by the nature of the substituents. The vanadium complex of a valine-derived diamine gave good results with a range of aromatic and aliphatic aldehydes. Georg Thieme Verlag Stuttgart.