Alternating Copolymerization of CO₂ and Cyclohexene Oxide by New Pyridylamidozinc(II) Catalysts

Abstract

Five new Zn­(II) complexes bearing pyridylamido ligands with different substituents at the pyridine and at the amido moieties were synthesized and evaluated as catalysts for the alternating copolymerization of carbon dioxide and cyclohexene oxide. Polymers with carbonate linkages ranging between 86 and 99% and a slightly isotactic-enriched structure were selectively obtained under a variety of reaction conditions, including 1 atm of CO2 pressure, without any cocatalyst. Some experimental and theoretical evidence suggested that different initiating species are involved in the catalytic cycle, including dimeric [(L x )­Zn­(μ-OR)]2 and [(L x )­Zn­(μ-O2COR)] complexes similar to those involved in the classical β-diiminate Zn­(II) catalysts.

Tuning the thermal properties of poly(ethylene)‐like poly(esters) by copolymerization of ε‐caprolactone with macrolactones, in the presence of a pyridylamidozinc(II) complex

“…Toluene was refluxed over Na and distilled under nitrogen. The pyridylamidozinc(II) complex (I) was synthesized following the literature procedure . All other reagents and solvents were purchased from Sigma‐Aldrich and used as received unless stated otherwise.…”

“…27 The influence of the main chain microstructure of the block and random copolymers on their thermal, rheological, and barrier properties was established. 34 In the framework of our interest in the ROP of macrolides, we wish to report the achievement of the homo-and copolymerization of 6HDL with ω-PDL and CL in the presence of a pyridylamidozinc(II) complex, which has been recently described by some of us for the copolymerization of CO 2 and epoxides 35 and for the block copolymerization of CL and lactides. 36 The copolymerization of ω-PDL with other lactones, having conventional ring-size, has been already described in the literature 27,[37][38][39][40][41][42][43][44] to give both block and random copolymers.…”

Iminopyridine Ni(II) Catalysts Affording Oily Hyperbranched Ethylene Oligomers and/or Crystalline Polyethylenes Depending on the Reaction Conditions: Possible Role of In Situ Catalyst Structure Modifications

“…Ligands L1-L6 and complexes 1-4 were synthesized as described in our previous papers [20][21][22]. Complexes 5-6 were synthesized following a procedure previously reported for similar complexes [23].…”

Tailor-made block copolymers of l-, d- and rac-lactides and ε-caprolactone via one-pot sequential ring opening polymerization by pyridylamidozinc(ii) catalysts

“…L 1 H-L 4 H and the zinc complexes L x ZnN(SiMe 3 ) 2 (x ¼ 1-4) were synthesized as previously reported. 44,50 Synthesis of complex L 1 ZnEt. In an Mbraun glovebox, a solution of the proligand L 1 H (0.200 g, 0.54 mmol) in dichloromethane (2.5 mL) was added dropwise into a solution of ZnEt 2 (0.073 g, 0.59 mmol) in dichloromethane (2.5 mL).…”