This Perspective article summarizes efforts paid in our group to develop efficient metal-based catalysts for the immortal ring-opening polymerization (iROP) of cyclic esters presence large amounts alcohols (ROH) as chain transfer agents. The catalyst systems reviewed include discrete organometallic complexes based on rare earths, magnesium, calcium and more specifically zinc, well simple employing metal triflate salts, notably Al(OTf)3, (stereo)controlled iROP lactide (LA), β-butyrolactone...

Abstract Metal‐based catalysts and initiators have played a pivotal role in the ring‐opening polymerization (ROP) of cyclic esters, thanks to their high activity remarkable ability control precisely architectures resulting polyesters terms molar mass, dispersity, microstructure, or tacticity. Today, after two decades extensive research, field is slowly reaching maturity. However, several challenges remain, while original concepts emerged around new types applications catalysis. This Review...

The ring-opening polymerization (ROP) of racemic trans-cyclohexene carbonate (rac-CHC) and enantiopure trans-(R,R)-CHC is successfully carried out with various catalyst systems. Poly(cyclohexene carbonate) (PCHC) a slight isotactic bias (Pm = ca. 60–76%) obtained by ROP rac-CHC catalyzed zinc diaminophenolate, β-diketiminate, yttrium bis(phenolate), or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) in combination an alcohol as co-initiator. Purely PCHC synthesized for the first time via (R,R)-CHC...

We report here on the ring-opening polymerization (ROP) of racemic β-thiobutyrolactone (rac-TBL), as first chemical synthesis poly(3-thiobutyrolactone) (P3TB), thioester analogue ubiquitous poly(3-hydroxybutyrate) (P3HB). The ROP reactions proceed very fast (TOF >12 000 h-1 at r.t.) in presence various metal-based catalysts. Remarkably, catalyst systems based non-chiral yttrium complexes stabilized by tetradentate amino alkoxy- or diamino-bis(phenolate) ligands {ONXOR1,R2 }2- (X=O, N)...

The ring-opening polymerization of ε-caprolactone initiated by Nd(BH4)3(THF)3, 1a, has been investigated. occurs rapidly (<5 min) and quantitatively at room temperature to give, in high yields, polymers which exhibit controlled molecular weights relatively low polydispersities. Initially, 3 mol may coordinate the neodymium center form Nd(BH4)3(ε-caprolactone)3 complex, 1b. Then, inserts into metal−borohydride hydrogen bond 1a or 1b give intermediate [(BH4)2Nd[O(CH2)5C(O)(HBH3)]], [i], each...

Abstract Six‐membered cyclic carbonates, namely trimethylene carbonate (TMC), 3,3‐dimethoxytrimethylene (DMTMC) and 3‐benzyloxytrimethylene (BTMC), undergo controlled “immortal” ring‐opening polymerization (iROP) under mild conditions (bulk, 60–150 °C), by using organocatalysts, including an amine [4‐ N , ‐dimethylaminopyridine (DMAP)], a guanidine [1,5,7‐triazabicyclo‐[4.4.0]dec‐5‐ene (TBD)], or phosphazene [2‐ tert ‐butylimino‐2‐diethylamino‐1,3‐dimethylperhydro‐1,3,2‐diazaphosphorine...

A simple isocyanate-free method to synthesize poly(trimethylene carbonate hydroxy-urethane)s is described. The strategy first involves the synthesis of α,ω-di(cyclic carbonate) telechelic polycarbonate precursors upon ring-opening polymerization trimethylene using a cyclic alcohol as chain transfer agent, followed by polyaddition terminal with diamine. Such poly(carbonate-hydroxyurethane)s exhibit macromolecular segments tunable length/molar mass.

A series of multiblock poly(ether carbonate urethane)s comprising poly(trimethylene carbonate), poly(ethylene glycol), and poly(propylene glycol) segments, with a molecular weight 60 000 g mol−1, were synthesized. Thermogelling behaviors the aqueous copolymer solutions observed at gelation concentrations as low 2 wt%. Rheological characterizations on thermogel carried out function temperature strain. The gels showed good recovery characteristics after being subjected to high sustained...

α,ω-Di(glycerol carbonate) telechelic poly(propylene glycol) (PPG), poly(ethylene (PEG), poly(ester ether) (PEE), and poly(butadiene) (PBD) have been synthesized through chemical modification of the corresponding α,ω-dihydroxy polymers (PPG-OH2, PEG-OH2, PEE-OH2 PBD-OH2, respectively). Tosylation polymer diols with 4-tosylmethyl-1,3-dioxolan-2-one (GC-OTs) afforded, in high yields, desired PPG, PEG, PEE PBD end-capped at both termini a five-membered ring cyclic glycerol carbonate...

The ring-opening polymerization of cyclic carbonate monomers derived from biomass feedstocks constitutes an attractive way to prepare polycarbonates that are potentially useful as high-tech materials or commodity "bioplastics". This process can be catalyzed by inherently different systems ranging simple basic organocatalysts, Lewis acidic metallic salts such triflates, more sophisticated discrete metallo-organic complexes oxophilic metals (zinc, yttrium). In this perspective, the most recent...

Abstract Alternating copolymers constitute an attractive class of materials. It was shown previously that highly alternated poly(β‐hydroxyalkanoate)s (PHAs) can be prepared by ring‐opening polymerization (ROP) mixtures two different enantiomerically pure 4‐alkyl‐β‐propiolactones. However, the approach could not extended to PHAs with chemically tunable functional groups, which is desirable access original advanced Reported herein first syndioselective and controlled ROP racemic allyl benzyl...

The synthesis of multi-arm poly([R]-3-hydroxybutyrate) (PHB)-based triblock copolymers (poly([R]-3-hydroxybutyrate)-b-poly(N-isopropylacrylamide)-b-[[poly(methyl ether methacrylate)-g-poly(ethylene glycol)]-co-[poly(methacrylate)-g-poly(propylene glycol)]], PHB-b-PNIPAAM-b-(PPEGMEMA-co-PPPGMA), and their subsequent self-assembly into thermo-responsive hydrogels is described. Atom transfer radical polymerization (ATRP) N-isopropylacrylamide (NIPAAM) followed by poly(ethylene glycol) methyl...

Origins of stereoselectivity in ROP racemic chiral cyclic esters promoted by achiral yttrium complexes, resulting the formation highly heterotactic polylactide, and syndiotactic or, more uniquely, isotactic poly(3-hydroxybutyrate)s, are discussed. A close interplay between nature ester, most particularly exocyclic functional chain installed on center β-lactones, ortho-substituents phenolate rings ligand, results various determining secondary interactions steric also electronic nature.

Reactions of Nd(BH4)3(THF)3 (1) with KCp* (Cp* = η-C5Me5), KC4Me4P, and K2C8H8 gave the organometallic derivatives (Cp*)Nd(BH4)2(THF)2 (2), [K(THF)][(C4Me4P)2Nd(BH4)2] (3), (COT)Nd(BH4)(THF)2 (4) (COT η-C8H8), respectively. Treatment 4 NEt3HBPh4 afforded cationic complex [(COT)Nd(THF)4][BPh4] (5). The mixed ring compound (COT)Nd(Cp*)(THF) (6), alkoxide [(COT)Nd(OEt)(THF)]2 (7), thiolates Na[(COT)Nd(StBu)2] (8) [Na(THF)2][{(COT)Nd}2(StBu)3] (9) were synthesized by treating or 5 alkali metal...

Poly(trimethylene carbonate) (PTMC) was synthesized through ring-opening polymerization by using a rare-earth borohydride initiator, [Sm(BH(4))(3)(thf)(3)]. This initiator shows high activity to give high-molar-mass PTMCs with molar-mass distributions ranging from 1.2 1.4, and regular structure void of ether linkages. The polymers were characterized (1)H (13)C NMR spectroscopy, (1)H-(1)H COSY, (1)H-(13)C HMQC size-exclusion chromatography (SEC), viscosimetry, MALDI-TOF MS analyses. A...

The monoborohydride lanthanide complex [Sm(Cp*)2(BH4)(thf)] (1a) (Cp* = eta-C5Me5), has been successfully used for the controlled ring-opening polymerization of epsilon-caprolactone (epsilon-CL). organometallic samarium(III) initiator 1 a produces, in quantitative yields, alpha,omega-dihydroxytelechelic poly(epsilon-caprolactone) displaying relatively narrow polydispersity indices (<1.3) within short period time (30 min). polymers have characterized by 1H and 13C NMR, SEC, MALDI-TOF MS...

Trivalent rare earth metal borohydride complexes Ln(BH4)3(THF)3 (Ln = La, Nd, Sm) initiate the ring-opening polymerization of ε-caprolactone (ε-CL) to give, in quantitative yields and a few minutes, α,ω-dihydroxytelechelic poly(ε-caprolactone) displaying relatively narrow molar mass distribution (≤1.3). The polymer features depend on both solvent. A good agreement between M̄n(theo) M̄n(exp) is observed for low [monomer]0/[initiator]0 values whereas deviation (M̄n(exp) < M̄n(theo)) obtained...

Cyclic carbonate surprise! Living controlled "immortal" bulk ring-opening polymerization of trimethylene proceeds in the presence β-diketiminate zinc amido catalyst precursor [Zn(bdi){N(SiMe3)2}] (bdi=CH(CMeNC6H3-2,6-iPr2)2) and benzyl alcohol as chain-transfer agent (see scheme). Catalytic amounts low 20 ppm allowed quantitative conversion up to 50000 monomer units within 2 h at 110 °C. Supporting information for this article is available on WWW under...

A series of pentamethylcyclopentadienyl bis(phosphinimino)methanide complexes yttrium and the lanthanides, [{CH(PPh2NSiMe3)2}Ln(η5-C5Me5)Cl] (Ln = Y (1a), Sm (1b), Yb (1c)), were prepared by two different synthetic approaches. The compounds can be obtained either from [{CH(PPh2NSiMe3)2}LnCl2]2 Y, Sm, Yb) K(C5Me5) or in a one-pot reaction when K{CH(PPh2NSiMe3)2} is reacted with anhydrous rare earth trichlorides presence K(C5Me5). When 1a−c combined situ 1 equiv 2-propanol, an active [Ln]-OiPr...

The amino poly(trimethylene carbonate)-NHt-Boc (PTMC-NHt-Boc) and poly(epsilon-caprolactone)-NH -Boc (PCL-NHt-Boc) were synthesized by ring-opening polymerization (ROP) of TMC or CL subsequently deprotected into the corresponding PTMC-NH2 PCL-NH2. These functional homopolymers used as macroinitiators for ROP gamma-benzyl-L-glutamate N-carboxyanhydride (BLG), consequently, giving respective diblock copolymers PTMC-b-PBLG PCL-b-PBLG in almost quantitative yields. (co)polymers have been...