215808-46-1Relevant articles and documents
Structure and reactivity of mono- and dinuclear diiminate zinc alkyl complexes
Allen, Scott D.,Moore, David R.,Lobkovsky, Emil B.,Coates, Geoffrey W.
, p. 137 - 148 (2007/10/03)
The synthesis, structure and reactivity of several diiminate ligands are presented. The syntheses of five representative β-diiminate (BDI) zinc alkyl complexes and one β-oxo-δ-diiminate (BODDI) zinc alkyl are described. BDI ligands with varying backbone and N -aryl substituents display different solid state structures. [(BDI)ZnR] are synthesized by the reaction of (BDI)H with ZnR2 in quantitative yield. Previously reported (BDI-1)ZnEt is a three-coordinate monomer in the solid state whereas [(BDI-3)ZnEt]∞ [(BDI-3)=2-((2,6-diisopropylphenyl) amido)-3-cyano-4-((2,6-diisopropylphenyl)imino-2-pentene] and [(BDI-4) ZnEt]∞ [(BDI-4)=2-((2,6-diethylphenyl)amido)-3-cyano-4- ((2,6-diethylphenyl)imino-2-pentene] form one dimensional coordination polymers. The bimetallic complex [(BODDI-1)(ZnEt)2] [(BODDI-1)=2,6-bis((2,6-diisopropylphenyl)amido)-2,5-heptadien-4-one] is prepared through the reaction of (BODDI-1)H2 with two equivalents ZnEt2. Both [(BDI)ZnEt] and [(BODDI)ZnEt] complexes react with acetic acid to give the acetate complexes in moderate to high yields, offering a superior synthetic route to these complexes. [(BDI)ZnR] [BDI=(BDI-3) or 1,1,1-trifluoro-2- ((2,6-diisopropylphenyl) amido)-4-((2,6-diethylphenyl)imino-2-pentene), (BDI-5)] complexes react with MeOH to produce [{(BDI)Zn(μ-OMe)} 2Zn(μ-OMe) 2] in moderate yields. The molecular structures of [(BDI-3)ZnEt], [(BDI-4)ZnEt], [(BODDI-1)(ZnEt) 2], [(BODDI-1) Zn2(μ-OAc)2], [{(BDI-3)Zn(μ-OMe)}2 Zn(μ-OMe)2] and [{(BDI-5)Zn(μ-OMe)}2 Zn(μ-OMe)2] have been determined by X-ray diffraction.
Single-site β-diiminate zinc catalysts for the alternating copolymerization of CO2 and epoxides: Catalyst synthesis and unprecedented polymerization activity
Cheng,Moore,Reczek,Chamberlain,Lobkovsky,Coates
, p. 8738 - 8749 (2007/10/03)
Synthetic routes to zinc β-diiminate complexes are reported. The synthesis of 11 β-diimine [(BDI)-H] ligands, with varying N-aryl substituents and bridging structures, is described. These ligands are converted to (BDI)ZnX complexes (X = OAc, Et, N(SiMe3)2, Br, Cl, OH, OMe, OiPr). X-ray structural data revealed that all zinc complexes examined exist as μ-X-bridged dimers in the solid state, with the exception of the zinc ethyl and amido complexes which were monomeric. Complexes of the form (BDI)ZnOR (R = alkyl, acyl) and (BDI)ZnN(SiMe3)2 are highly active catalysts for the alternating copolymerization of epoxides and CO2. Copolymerizations of cyclohexene oxide (CHO) and CO2 with (BDI-1)ZnX [(BDI-1) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)imino)-2-pentene)] and (BDI-2)ZnX [(BDI-2) = 2-((2,6-diethylphenyl-amido)-4-((2,6-diethylphenyl)imino)-2-pentene)], where X = OAc, Et, N(SiMe3)2, Br, Cl, OH, OMe, OiPr, were attempted at 50 °C and 100 psi CO2. Complexes with X = OAc, N(SiMe3)2, OMe, OiPr all produced polycarbonate by the alternated insertion of CHO and CO2 with similar catalytic activities, comparable molecular weights, and narrow molecular weight distributions (MWD ～ 1.1), indicating the copolymerizations are living. Furthermore, ligand effects were shown to dramatically influence the polymerization activity as minor steric changes accelerated or terminated the polymerization activity.
