Lactide polymerization by well-defined calcium coordination complexes: comparisons with related magnesium and zinc chemistry.
نویسندگان
چکیده
Amide and alkoxide coordination complexes of calcium supported by beta-diiminato and bulky trispyrazolylborate complexes are reported together with their activity in lactide ring-opening polymerization; some are amongst the most active systems discovered to date.
منابع مشابه
Different mechanisms at different temperatures for the ring-opening polymerization of lactide catalyzed by binuclear magnesium and zinc alkoxides.
Two binuclear magnesium and zinc alkoxides supported by a bis-salalen type dinucleating heptadentate Schiff base ligand were synthesized and fully characterized. The two complexes are efficient initiators for the ring-opening polymerization (ROP) of L-lactide, affording polymers with narrow polydispersities and desirable molecular weights. Interestingly, the mechanisms for the ROP of lactide ar...
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A series of zinc(II) and magnesium(II) alkoxides based upon a beta-diiminate ligand framework has been prepared. [(BDI-1)ZnO(i)Pr](2) [(BDI-1) = 2-((2,6-diisopropylphenyl)amido)-4-((2,6-diisopropylphenyl)imino)-2-pentene] exhibited the highest activity and stereoselectivity of the zinc complexes studied for the polymerization of rac- and meso-lactide to poly(lactic acid) (PLA). [(BDI-1)ZnO(i)()...
متن کاملZinc and cobalt complexes based on tripodal ligands: synthesis, structure and reactivity toward lactide.
The coordination chemistry of a series of pro-ligands ([L¹]-[L⁶]) with cobalt and zinc derivatives has been studied. All complexes have been characterized by multinuclear NMR, elemental analysis, and by single-crystal X-ray diffraction studies. Polymerization of rac-lactide takes place at 130 °C in the presence of cobalt and zinc complexes to yield polymers under solvent free conditions with co...
متن کاملEthyl 2-hydroxy-2-methylpropanoate derivatives of magnesium and zinc. The effect of chelation on the homo- and copolymerization of lactide and ε-caprolactone.
The preparation, single crystal and molecular structures of the compounds (BDI)Mg(OCMe2COOEt)(L) are described where BDI = 2-[(2,6-diisopropylphenyl)amino]-4-[(2,6-diisopropylphenyl)imino]pent-2-ene and L = pyridine (py) and 4-dimethylaminopyridine (DMAP). In the solid-state the molecules have five coordinate Mg(2+) ions that may be considered as derived from a trigonal bipyramid where the chel...
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ورودعنوان ژورنال:
- Chemical communications
دوره 1 شماره
صفحات -
تاریخ انتشار 2003