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...

A new heteroleptic ethyl-zinc complex stabilized by a chelating bis(morpholinomethyl)phenoxy ligand has been synthesised and shown to be highly potent initiator for the immortal ring-opening polymerisation (ROP) of lactide β-butyrolactone, being able convert up 50 000 equiv. monomer in presence 1000 an alcohol as transfer agent. Two related complexes magnesium calcium have also prepared. These are stable solution, even large amounts alcohol, constitute effective catalysts ROP under mild conditions.

The ruthenium catalysed direct functionalisation of arene C–H bonds by aryl halides is reported. Reactions were performed in diethyl carbonate (DEC) instead N-methylpyrrolidone (NMP), the solvent choice used most bond transformations. use facilitates workup procedure thus reducing amount waste water. slight loss activity due to counterbalanced improvement catalyst efficiency achieved a judicious additives. Several arenes containing an N-heterocycle as directing group have been diarylated.

The syntheses of the homoleptic compounds Ae[N(SiMe2H)2]2(THF)x (Ae = Ca, x 1, 2; Sr, 2/3, 3; Ba, 0, 4) are reported. They can be prepared by salt metathesis involving alkaline-earth metal iodides and KN(SiMe3)2 (1) or transamination between Ae[N(SiMe3)2]2(THF)2 HN(SiMe2H)2. These precursors constitute convenient starting materials for subsequent preparation {LnO}AeN(SiMe2H)2 heteroleptic complexes large metals, as exemplified {LO3}AeN(SiMe2H)2 ({LO3}−...

A family of heteroleptic complexes zinc and magnesium supported by bulky multidentate amino-ether phenolate ligands has been developed; in combination with external chain transfer agents, they constitute efficient binary catalytic systems for the immortal ring-opening polymerisation cyclic esters.

Abstract Well‐defined, base free cations of zinc and the alkaline‐earth metals (Mg, Ca, Sr, Ba) supported by a multidentate phenolate ligand stabilized perfluorinated weakly coordinating counterions are readily available simple procedures; solid‐state structures magnesium calcium derivatives were elucidated. Upon treatment with an excess i PrOH, these complexes generate highly efficient binary catalytic systems for immortal ring‐opening polymerization L ‐lactide, yielding poly( ‐lactide)s...

Several new heteroleptic Sn(II) complexes supported by amino-ether phenolate ligands [Sn{LO(n)}(Nu)] (LO(1)=2-[(1,4,7,10-tetraoxa-13-azacyclopentadecan-13-yl)methyl]-4,6-di-tert-butylphenolate, Nu=NMe(2) (1), N(SiMe(3))(2) (3), OSiPh(3) (6); LO(2)=2,4-di-tert-butyl-6-(morpholinomethyl)phenolate, Nu=N(SiMe(3))(2) (7), (8)) and the homoleptic Sn{LO(1)}(2) (2) have been synthesized. The alkoxy derivatives [Sn{LO(1)}(OR)] (OR=OiPr (4), (S)-OCH(CH(3))CO(2)iPr (5)), which were generated...

Stable germanium(II) and lead(II) amido complexes {LO(i)}M(N(SiMe3)2) (M = Ge(II), Pb(II)) bearing amino(ether)phenolate ligands are readily available using the proteo-ligands {LO(i)}H of general formula 2-CH2NR2-4,6-tBu2-C6H2OH (i 1, NR2 N((CH2)2OCH3)2; i 2, NEt2; 3, aza-15-crown-5) M(N(SiMe3)2)2 precursors. The molecular structures these germylenes plumbylenes, as well those {LO(3)}GeCl, {LO(3)}SnCl congeneric {LO(4)}Sn(II)(N(SiMe3)2) where aza-12-crown-4, have been determined...

A kinetic analysis of the metal-catalyzed immortal ring-opening polymerization (ROP) cyclic esters is presented, based on a first-principles approach without making assumptions regarding active species. The kinetics all ROP reactions performed with metal catalyst and an exogenous chain transfer agent are characterized by initiation, propagation exchange rate constants (ki, kp, ke, respectively). Curve fitting to this scheme in initial stage allows extraction ki kp from single experiment....

The polymerization of ε-caprolactone is reported using various bifunctional chain transfer agents and a dizinc catalyst. Conventionally, it assumed that agent (CTA), will be initiated from both functional groups; however, in this study assumption not always substantiated. different architectures microstructures poly(ε-caprolactone) samples (PCL) are compared series monofunctional alcohols as the agents, including trans-1,2-cyclohexanediol (CHD), ethylene glycol (EG), 1,2-propanediol (PD),...

Abstract Vinyl thianthrenium salt is a compound with interesting electrophilic properties capable of reacting two distinct nucleophiles. By using β‐keto esters as one the reaction partners, it possible to insert chain carbon atoms further functionalization under mild conditions. We have studied this new methodology which involves stepwise formation C−C and C−X bond (with X=N, O, etc.) in step without use metals. Depending on conditions starting ketoester, varied reactivity has been observed...

Abstract An efficient, practical, and industrially relevant procedure for the production of polymer materials, in which a part oil‐derived polyolefins has been replaced by renewable, biodegradable, biocompatible poly(lactide) block, is presented. Binary catalytic systems combining innocuous metals (yttrium, zinc, magnesium, or calcium) bifunctional alcohols (acting as transfer agents) were developed to promote immortal ring‐opening polymerization lactide directly styrene. Up 20 000...