Nacnac(Bn)CuOiPr: a strained geometry resulting in very high lactide polymerization activity.
نویسندگان
چکیده
N,N'-Dibenzyl diketiminate copper isopropanolate, (nacnac(Bn)CuOiPr)(2), polymerizes rac- and S,S-lactide in the presence or absence of isopropanol as a chain-transfer reagent with very high activity (k(2) = 32 M(-1) s(-1)), narrow polydispersities and without evidence of side reactions such as transesterification, epimerization or catalyst decomposition.
منابع مشابه
Nacnac(Bn)MgOtBu: a diketiminate-based catalyst for the polymerisation of rac-lactide with slight isotactic preference.
The reaction of N,N'-dibenzyl-2-amino-4-imino-pent-2-ene, nacnac(Bn)H, with 1 or 2 equiv. of MgnBu₂ afforded the homoleptic complex nacnac(Bn)₂Mg. The reaction of nacnac(Bn)H with Mg(N(SiMe₃)₂)₂ yielded nacnac(Bn)MgN(SiMe₃)₂, which reacted with tert-butanol to form nacnac(Bn)MgOtBu. The latter complex crystallizes as an alkoxide bridge dimer and is active in the ring-opening polymerisation of r...
متن کاملExceptionally high lactide polymerization activity of zirconium complexes with bridged diketiminate ligands.
A cyclohexanediyl-bridged, bis(N-xylyl) diketiminate ligand, (±)-C6H10(nacnac(Xyl)H)2, LH2 (Xyl = 2,6-dimethylphenyl), was obtained from the reaction of [(2,6-dimethylphenyl)amino]-pent-3-en-2-one first with Meerwein's salt, then with (±)-cyclohexanediamine. The reaction of the ligand with Zr(NMe2)4 yielded LZr(NMe2)2. Protonation of the remaining diamide ligands with EtOH or [H2NMe2]Cl yielded...
متن کاملSynthesis and Thermal Properties of Novel Biodegradable ABCBA Pentablock Copolymers from Poly (Ethylene glycol), L-Lactide and p-Dioxanone
In this work, new biodegradable ABCBA type pentablock copolymers with different mole ratio of L-lactide and PPDO-b-PEG-b-PPDO triblock copolymer were synthesized and characterized. In the first step, PPDO-b-PEG-b-PPDO triblock copolymer was synthesized via a ring-opening polymerization of P-DiOxanone (PDO) monomer with Poly (Ethylene Glycol) (P...
متن کاملSyntheses and structures of lanthanide borohydrides supported by a bridged bis(amidinate) ligand and their high activity for controlled polymerization of ε-caprolactone, L-lactide and rac-lactide.
Metathesis reaction of LLnCl(THF)(2) [L = (Me(3)SiNC(C(6)H(5))N)(2)(CH(2))(3)] with NaBH(4) in a 1 : 1.5 molar ratio in THF (THF = tetrahydrofuran) at 60 °C afforded the monoborohydride LLn(BH(4))(DME) [Ln = Y (1), Nd (2), Sm(3) and Yb(4)] crystallized from DME solution (DME = dimethoxyethane). Crystal structure analyses revealed 1-4 are monomers, in which each metal is ligated by one L ligand,...
متن کاملMonomethylaluminum and dimethylaluminum pyrrolylaldiminates for the ring-opening polymerization of rac-lactide: effects of ligand structure and coordination geometry.
Two series of aluminum alkyl complexes supported by pyrrolylaldiminate ligands, LAlMe2 (1a-7a) and L2AlMe (1b-7b), were successfully synthesized and characterized by NMR spectroscopy and elemental analysis. Reactions of trimethylaluminum with the corresponding pyrrolylaldiminate ligands in the molar ratios of 1 : 1 and 1 : 2 yielded dimethylaluminum pyrrolylaldiminates (1a-7a) and monomethylalu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemical communications
دوره 48 83 شماره
صفحات -
تاریخ انتشار 2012