Strained metal bonding environments in methylindium dithiolates and their reactivity as initiators for the ring-opening polymerization of cyclic esters

Briand, Glen G.; Cairns, Stefan A.; Decken, Andreas; Dickie, Courtney M.; Kostelnik, Thomas I.; Shaver, Michael P.

doi:10.1016/j.jorganchem.2016.01.020

Cited by 9 publications

(4 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“… Subsequent to our initial report, a variety of indium-based initiators have been reported in the literature for the polymerization of lactide (Figure ). − In this Account, we present an overview of our efforts to develop indium-based catalyst systems for the synthesis of novel and commercially relevant biodegradable polymers.…”

Section: Introductionmentioning

confidence: 99%

Indium Catalysts for Ring Opening Polymerization: Exploring the Importance of Catalyst Aggregation

Osten

Mehrkhodavandi

2017

Acc. Chem. Res.

View full text Add to dashboard Cite

Inexorably, the environmental persistence and damage caused by polyolefins have become major drawbacks to their continued long-term use. Global shifts in thinking from fossil-fuel to renewable biobased resources have urged researchers to focus their attention on substituting fossil-fuel based polymers with renewable and biodegradable alternatives on an industrial scale. The recent development of biodegradable polyesters from ring opening polymerization (ROP) of bioderived cyclic ester monomers has emerged as a promising new avenue toward this goal. Ever increasing numbers of metal-based initiators have been reported in the literature for the controlled ROP of cyclic esters, in particular for the polymerization of lactide to produce poly(lactic acid) (PLA). PLA has several material weaknesses, which hinder its use as a replacement for commodity plastics. Despite many advances in developing highly active and controlled catalysts for lactide polymerization, no single catalyst system has emerged to replace industrially used catalysts and provide access to PLA materials with improved properties. We reported the first example of indium(III) for the ring opening polymerization of lactide. Since then, indium(III) has emerged as a useful Lewis acid in initiators for the controlled polymerization of lactide and other cyclic esters. In particular, we have developed a large family of chiral dinuclear indium complexes bearing tridentate diaminophenolate ligands and tetradentate salen and salan ligands. Complexes within our tridentate ligand family are highly active initiators for the moderately isoselective living and immortal polymerization of rac-lactide, as well as other cyclic esters. We have shown that subtle steric effects influence aggregation in these systems, with polymerization typically proceeding through a dinuclear propagating species. In addition, profound effects on polymerization activities have been observed for central tertiary versus secondary amine donors in these and other related systems. In contrast, our well-controlled and highly active chiral indium salen systems are more isoselective than the tridentate analogues and polymerize lactide via a mononuclear propagating species. Again, we have noticed that subtle steric and electronic changes to the ligand can influence both polymerization activity and stereoselectivity via aggregation phenomena. Recently, we have reported a promising new chiral indium catalyst supported by a tetradentate salan ligand. This catalyst is remarkably water and air stable and can be activated by linear and branched alcohols to provide controlled access to multiblock copolymers in air. This catalyst represents an important step forward toward generating new, commercially relevant catalysts for ROP of cyclic esters to produce novel biodegradable polymers, and highlights the unique value of indium-based catalysts in the field.

show abstract

Section: Introductionmentioning

confidence: 99%

Indium Catalysts for Ring Opening Polymerization: Exploring the Importance of Catalyst Aggregation

Osten

Mehrkhodavandi

2017

Acc. Chem. Res.

View full text Add to dashboard Cite

show abstract

“…DFT calculations were performed to provide insight into the preference for the observed dinuclear mono‐pyridine structure 1 versus the mononuclear bis‐pyridine structure [MeIn(tdt)(py) 2 ], [37] which would have an analogous indium bonding environment to 2 . The energies ( E ) associated with the formation of these structures may be calculated using Equations 1 and 2 (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Structure and Reactivity of Organoindium 1,2‐Benzenedithiolates and 2‐Amidobenzenethiolates

et al. 2022

Self Cite

View full text Add to dashboard Cite

Organoindium compounds of redox active 1,2-benzenedithiolate and 2-amidobenzenethiolate ligands were synthesized and tested for reactivity against mild oxidants. The reaction of Me 3 In and (NCN)InMe 2 [NCN = 2,6-bis(dimethylaminomethy)phenyl] with 3,4-toluenedithiol (H 2 tdt) at room temperature afforded [MeIn(tdt)(py)] 2 (1) and (NCN)In(tdt) (2), respectively. A similar reaction of Me 3 In with 2-aminobenzenethiol (H 2 abt) in toluene under reflux afforded [MeIn(abt)(py)] 2 (3). The reaction of (NCN)InCl 2 with one equivalent of Li 2 (abt) or two equivalents of Li(Habt) afforded the compounds [(NCN)In(abt)]•LiCl(thf) 2 (4•LiCl(thf) 2 ) and (NCN)In(Habt) 2 (5), respectively. The X-ray crystal structures of 1 and 3 are similar and show dimeric structures via μ-S-(tdt) and μ-N-(abt) ligands, respectively. Compounds 2 and 4 possess similar monomeric structures and tridentate NCN pincer ligands. DFT computational studies have been used to rationalize the observed solid-state structures and discern the potential reactivity of compounds 1-4 against oxidants. The reaction of 1 and 2 with excess iodine resulted in loss of the 3,4-toluenedithiolate ligand and the formation of the oligomeric disulfide [tdt] n , while 3 and 4 showed no reactivity under similar conditions. This contrasts the reactivity of previously reported organoindium o-amidophenolate complexes which undergo oxidative addition of iodine to afford ligand-centered radical species.

show abstract

“…Methylindium dithiolates [MeIn(S 2 R)] have been shown to be useful compounds for the ring-opening polymerization (ROP) of cyclic esters to produce biodegradable polymers (Allan et al, 2013;Briand et al, 2016). These compounds are prepared from the stoichiometric reaction of InMe 3 with polydentate amino/oxo-dithiols.…”

Section: Chemical Contextmentioning

confidence: 99%

“…However, the steric bulk of the (Me 3 Si) 3 C precludes further intermolecular InÁ Á ÁS bonding and the indium atoms are restricted to a four-coordinate distorted tetrahedral bonding environment. Other reported methylindium dithiolates employ polydentate dithiolate ligands, some of which possess dimeric and trimeric structures (Briand et al, 2016).…”

Section: Database Surveymentioning

confidence: 99%

Synthesis and crystal structure of bis(μ-2-methylbenzenethiolato-κ²S:S)bis[methyl(2-methylbenzenethiolato-κS)indium(III)]

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

Strained metal bonding environments in methylindium dithiolates and their reactivity as initiators for the ring-opening polymerization of cyclic esters

Cited by 9 publications

References 56 publications

Indium Catalysts for Ring Opening Polymerization: Exploring the Importance of Catalyst Aggregation

Indium Catalysts for Ring Opening Polymerization: Exploring the Importance of Catalyst Aggregation

Synthesis, Structure and Reactivity of Organoindium 1,2‐Benzenedithiolates and 2‐Amidobenzenethiolates

Synthesis and crystal structure of bis(μ-2-methylbenzenethiolato-κ²S:S)bis[methyl(2-methylbenzenethiolato-κS)indium(III)]

Contact Info

Product

Resources

About

Strained metal bonding environments in methylindium dithiolates and their reactivity as initiators for the ring-opening polymerization of cyclic esters

Cited by 9 publications

References 56 publications

Indium Catalysts for Ring Opening Polymerization: Exploring the Importance of Catalyst Aggregation

Indium Catalysts for Ring Opening Polymerization: Exploring the Importance of Catalyst Aggregation

Synthesis, Structure and Reactivity of Organoindium 1,2‐Benzenedithiolates and 2‐Amidobenzenethiolates

Synthesis and crystal structure of bis(μ-2-methylbenzenethiolato-κ2S:S)bis[methyl(2-methylbenzenethiolato-κS)indium(III)]

Contact Info

Product

Resources

About

Synthesis and crystal structure of bis(μ-2-methylbenzenethiolato-κ²S:S)bis[methyl(2-methylbenzenethiolato-κS)indium(III)]