Two dinuclear aluminum complexes bearing dinaphthalene bridging Schiff bases have been synthesized and investigated as catalysts in ring-opening polymerization (ROP) of cyclic esters such rac-lactide (rac-LA) ε-caprolactone (ε-CL) the copolymerization (ROCOP) phthalic anhydride (PA) with cyclohexene oxide (CHO) limonene (LO). The polymerizations were living, producing polymers narrow molar mass distributions. Kinetic studies showed that first order respect to monomers. Cooperative effects...

A simple zinc catalyst showing high activity for both the synthesis of polylactide, a biodegradable polymer produced from renewable feedstock, and its degradation was described. In ring-opening polymerization lactides, showed one highest activities reported in literature reactions carried out solution at room temperature. This excellent performance preserved even when process performed under industrial conditions: temperature, absence solvent, by using low loading with unpurified monomers....

Robust homoleptic zinc catalysts offer new opportunities for recycling polyesters such as poly(lactic acid) and poly(ethylene terephthalate) to obtain platform molecules in a plastics circular economy approach.

A series of zinc complexes supported by tridentate imino-phenolate ligands with different substituents on the phenolate ring and bearing a pyridyl as an additional coordinative fragment were synthesized aim elucidating structure-to-activity relationships in ring-opening polymerization (ROP) cyclic esters. For all complexes, dynamic behavior associated conformational flexibility metallacycles involving pyridinic nitrogen was observed. In presence 2-propanol, promoted, high efficiency control,...

Phenoxy-imine aluminum complexes, in combination with DMAP, produce efficient catalysts for the alternating copolymerization of epoxides and anhydrides. A zwitterionic species is formed initiation step.

Abstract In this contribution, the catalytic behavior of a phenoxy‐imine aluminum catalyst and bimetallic salen complex in ring‐opening polymerization (ROP) macrolactones such as ω‐pentadecalactone (PDL), ω‐6‐hexadecenlactone (HDL) ethylene brassylate (EB), copolymerization (ROCOP) cyclohexene oxide (CHO) phthalic anhydride (PA) is described. A significant difference terms activity emerged between two catalysts ROP macrolactones, while similar behaviors were observed ROCOP process. The...

Salen, Salan, and Salalen chromium (III) chloride complexes have been investigated as catalysts for the ring-opening copolymerization reactions of cyclohexene oxide (CHO) with CO2 phthalic anhydride (PA) limonene (LO) or (CHO). In production polycarbonates, more flexible skeleton salalen salan ancillary ligands favors high activity. Differently, in epoxides, salen complex showed best performance. Diblock polycarbonate-polyester copolymers were selectively obtained by one-pot procedures from...

A mononuclear magnesium complex Mg(OC^tBu₂Ph)₂(THF)₂ catalyzes the active polymerization of cyclic esters and alternating co-polymerization epoxides with anhydrides.

A synthetic strategy for the preparation of a new class ligands is introduced. The bis(aldimine‐thioether‐phenolate) bear two anionic oxygen donors from phenolate moieties, neutral sulfur and nitrogen belonging, respectively, to thioether aldimine functionalities. so designed OSNNSO show coordinative pockets thus should be able host metallic centers. Instead, aldimine‐thioether‐phenolate OSN are tridentate which may form monometallic complexes. Two one this class, have been synthesized....

Abstract We report the synthesis of new hexadentate ligands bearing imine and pyridine nitrogen neutral donors with a binaphthol backbone. Such have been tailored to two coordinative pockets thus promoting formation bimetallic complexes. By direct reaction enantiomerically pure racemic ligand equivalents zinc amide precursor, complexes S‐ 1 rac ‐ were respectively obtained. Both highly active in polymerization lactides under several conditions, preserving exceptional activities even when...

Abstract Two zinc complexes bearing NHC ligands were synthesized and fully characterized by NMR spectroscopy. Their behavior in the Ring‐Opening Polymerization (ROP) of lactides was investigated under several conditions reaction. They showed to be efficient initiators, producing polylactides with molecular weights depending on cocatalysts. Microstructural analysis poly( rac ‐LA) 1 H spectroscopy revealed a slightly enriched‐heterotactic PLAs P r values up 0.66. Inspection kinetic parameters...

Chromium and aluminum complexes bearing salalen ligands were explored as catalysts for the ring-opening copolymerization (ROCOP) of succinic (SA), maleic (MA), phthalic (PA) anhydrides with several epoxides: cyclohexene oxide (CHO), propylene (PO), limonene (LO). Their behavior was compared that traditional salen chromium complexes. A completely alternating enchainment monomers to provide pure polyesters achieved all when used in combination 4-(dimethylamino)pyridine (DMAP) cocatalyst....

In this paper, we use mono- and bimetallic complexes based on Earth-abundant, cheap benign zinc for the synthesis of sustainable aliphatic semi-aromatic polyesters. Tridentate hexadentate aldimine-thioetherphenolate ligands were used to obtain desired by reaction proligands with opportune equivalents bis[bis(trimethylsilyl)amide]. The obtained 1 2 monometallic complex 3 as catalysts in Ring-Opening Polymerization (ROP) landmark cyclic esters, such ε-caprolactone lactide, COPolymerization...

Simple and commercially available metal amides are investigated as catalysts for the chemical depolymerization of polyesters commercial interest such polylactide (PLA) polyethylene terephthalate (PET) via alcoholysis. In alcoholysis reactions performed with methanol or ethanol at room temperature, Zn, Mg, Y showed highest activities, while group 4 metals were revealed poor catalysts. During ethanolysis PLA higher temperatures glycolysis PET, good activity Zn amide was preserved, Mg amides, a...

Backbone substituted NHC derivatives of the zinc and magnesium, in presence alcohol initiators, have been shown to be effective catalysts for ring-opening polymerization different cyclic monomers,...

The functionalization of carbon black (CB) represents a promising strategy to enhance its compatibility with polymers while addressing sustainability concerns. In this study, solvent-free mechanochemical approach (ball milling) is proposed for the oxidized (oCB) post-consumed polylactic acid (PLA), overcoming environmental drawbacks conventional methods that mostly rely on toxic solvents and catalysts. functionalized (f-CB) was characterized by Fourier transform infrared spectroscopy (FTIR),...

Homoleptic and heteroleptic zinc magnesium complexes bearing phenoxy-imine pyridine ligands were synthetized characterized. Several structural parameters such as the structure of ancillary ligand, nature metal centre coordination geometry investigated for identifying design elements purposeful to improve catalytic activity in ring opening polymerization (ROP) lactide reverse reaction degradation polylactide by alcoholysis. High efficiency control degree reached with catalysts while ones...