Active Ga-catalysts for the ring opening homo- and copolymerization of cyclic esters, and copolymerization of epoxide and anhydrides.

A series of gallium complexes L12Ga4Me8 (1), L22Ga4Me8 (2), and L32Ga4Me8 (3) was synthesized by reaction of GaMe3 with Schiff base ligands L1-3H2 (L1H2 = 2,4-di-tert-butyl-6-{[(3-hydroxypropyl)imino]methyl}phenol; L2H2 = 2,4-dichloro-6-{[(3-hydroxypropyl)imino]methyl}phenol; L3H2 = 4-tert-butyl-2-{[(3-hydroxypropyl)imino]methyl}phenol) and characterized by 1H, 13C NMR, IR spectroscopy, elemental analysis and single crystal X-ray analysis (1, 2), proving their tetranuclear structure in the solid state. Complexes 1-3 showed good catalytic activity in the ring opening homopolymerization (ROP) and ring opening copolymerization (ROcoP) of lactide (LA) and ε-caprolactone (ε-CL) in the presence of benzyl alcohol (BnOH) in toluene at 100 °C, yielding polymers with the expected average molecular weights (Mn) and narrow molecular weight distributions (MWD), as well as a high isoselectivity for the ROP of rac-lactide (rac-LA), yielding isotactic-enriched PLAs with Pm values up to 0.78.

Terpolymer Multicompartment Nanofibers as Templates for Hybrid Pt Double Helices.

Hybrid inorganic/block copolymer (BCP) materials have become increasingly relevant for application in heterogeneous catalysis, microelectronics, and nanomedicine. While block copolymer templates are widely used for the formation of inorganic nanostructures, multicompartment templates could give access to more complex shapes and inner structures that are challenging to obtain with traditional processes. Here, we report the formation and characterization of hybrid platinum/polymer helices using multicompartment nanofibers (MCNFs) of polystyrene--polybutadiene--poly(-butyl methacrylate) (PS--PB--PT) triblock terpolymers as templates.

Syntheses, structures and catalytic activity of tetranuclear Mg complexes in the ROP of cyclic esters under industrially relevant conditions.

Four tetranuclear magnesium complexes were synthesized and fully characterized. They are excellent catalysts for the ring-opening polymerization (ROP) of bulk racemic-lactide (rac-LA) and ε-caprolactone (ε-CL) even with low catalyst loading under industrially relevant conditions without additional co-initiators, yielding polymers with high molecular weight (Mn) and moderately controlled molecular weight distribution (MWD). The polymerization activity depends on the steric and electronic properties of the imino(phenolate) ligands.

Heterolepic -Ketoiminate Zinc Phenoxide Complexes as Efficient Catalysts for the Ring Opening Polymerization of Lactide.

Zinc phenoxide complexes LZnOAr - (L=MeNCHNC(Me)CHC(Me)O) and LZnOAr - (L=MeNCHNC(Me)CHC(Me)O) with donor-functionalized -ketoiminate ligands (L) and OAr substituents (Ar=Ph , ; 2,6-Me-CH , ; 3,5-Me-CH , ; 4-Bu-CH , ) with tuneable electronic and steric properties were synthesized and characterized. - adopt binuclear structures in the solid state except for , while they are monomeric in CDCl solution. - are active catalysts for the ring opening polymerization (ROP) of lactide (LA) in CHCl at ambient temperature and the catalytic activity is controlled by the electronic and steric properties of the OAr substituent, yielding polymers with high average molecular weight ( ) and moderately controlled molecular weight distribution (MWDs).