Cyclic polylactide synthesis initiated by a lithium anthraquinoid: understanding the selectivity through DFT and diffusion NMR

Martínez, Cristina Ruiz; Pérez, Juana M.; Arrabal-Campos, Francisco M.; Batuecas, M.T.; Ortuño, Manuel Á.; Fernández, Ignacio

doi:10.1039/d1py00547b

Cited by 5 publications

(21 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Simplifying eq , an empirical scaling relationship is obtained: , where k and a are variables specific to the polymer system that encompass the shape and density of the polymers in a given solvent and changes to solution viscosity (η) caused by polymer size. This relationship has been extended to the weight-average molecular weight ( M w ), with calculated molecular weights comparing well with those from GPC for a range of polymer samples. , …”

mentioning

confidence: 99%

Rapid Online Analysis of Photopolymerization Kinetics and Molecular Weight Using Diffusion NMR

et al. 2022

View full text Add to dashboard Cite

Online, high-throughput molecular weight analysis of polymerizations is rare, with most studies relying on tedious sampling techniques and batchwise postanalysis. The ability to track both monomer conversion and molecular weight evolution in real time could underpin precision polymer development and facilitate study of rapid polymerization reactions. Here, we use a single time-resolved diffusion nuclear magnetic resonance (NMR) experiment to simultaneously study the kinetics and molecular weight evolution during a photopolymerization, with in situ irradiation inside the NMR instrument. As a model system, we used a photoinduced electron transfer reversible addition− fragmentation chain transfer (PET-RAFT) polymerization. The data allow diffusion coefficients and intensities to be calculated every 14 s from which the polymer size and monomer conversion can be extracted. Key to this approach is (1) the use of shuffled gradient amplitudes in the diffusion NMR experiment to access reactions of any rate, (2) the addition of a relaxation agent to increase achievable time resolution and, (3) a sliding correction that accounts for viscosity changes during polymerization. Diffusion NMR offers a uniquely simple, translatable handle for online monitoring of polymerization reactions.

show abstract

mentioning

confidence: 99%

Rapid Online Analysis of Photopolymerization Kinetics and Molecular Weight Using Diffusion NMR

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Estimated cEF shown by circle size, except for organocatalyst 10 (x). Compound 1 is unpublished; other data from references as indicated ( 2 , 3 – 5 , 6 , 7 , 8 , 9 , 10 ).…”

Section: Sustainability’s Shades Of Graymentioning

confidence: 99%

Sustainable Polymers: Our Evolving Understanding

Getzler

Mathers

2022

Acc. Chem. Res.

View full text Add to dashboard Cite

Metrics & MoreArticle Recommendations * sı Supporting Information CONSPECTUS: This Account discusses the evolution of our strategy to conduct environmentally responsible research in the field of polymer chemistry. To contextualize our work, we begin with a broad historical overview of the modern environmental movement, the rise of sustainability as a concept, and how chemistry has responded to these forces, which were often sharply critical of our field. We then trace our own responses, from graduate school onward, chronicling a series of experiences and research projects that molded, challenged, and reshaped how we think about sustainability in polymer science. Since beginning our independent careers in 2004, we have recognized and worked to resolve the tension between designing synthetic polymers for specific desired thermomechanical properties and minimizing environmental impact. In our early years, we were most strongly guided by the 12 Principles of Green Chemistry (12PGC), which had only recently been proposed. The authors' early research agendas had a rather narrow focus on two areas, specifically catalysis and biobased monomers, which we saw as strongly linked to sustainability. Over time, we found these areas to be too narrow in their focus, ignoring important considerations such as the capacity of monomer supply to support scale-up and the impact polymers have at the end of their usage lifetimes. With respect to monomers and catalysts, we consider descriptive metrics that quantify waste production and the toxicity of compounds used during synthesis. In terms of polymer end-of-life, we discuss hydrophobicity as a tool to help understand susceptibility to degradation in the environment as well as some of the concerns with design for degradation, a critical component of 12PGC. Now, after nearly two decades of investigation, we believe that achieving sustainability in polymer science will require us to move beyond the qualitative use of the 12PGC to a portfolio of metrics. We note a heartening increase in the availability and use of such metrics and tools across the field. These include items that provide limited insight but are relatively trivial to integrate into existing workflows such as E factor or the Toxicity Estimation Software Tool. We also appreciate the increased use of Life Cycle Assessment (LCA), which is both dramatically more thorough and difficult to deploy. Finally, we propose the creation of a national LCA center, similar to instrumental core facilities. Such a resource would enable the use of this tool across multiple phases of research and we hope would more effectively guide us to a sustainable future.

show abstract

“…The aggregation state of the catalytic species is of crucial importance due to its influence on the selectivity of linear versus cyclic polymers. 15 A series of monomeric lithium amine-bis(phenolate) described by Dean et al 16 and Devaine-Pressing et al 17 and phenoxo-imine complexes reported by García-Valle et al 18 (Scheme 1) have been tested in the ROP of l - and rac -LA, affording cyclic polymers.…”

Section: Introductionmentioning

confidence: 99%

“…21 In 2020, Kricheldorf and coworkers provided mechanistic insights into the formation of low and high molecular weight cycles by back-biting and end-to-end cyclization, 22 and some of us also reported on the aggregation state of lithium catalysts as the property controlling the cyclic versus linear path. 15…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Lithium anthraquinoids as catalysts in the ROP of lactide and caprolactone into cyclic polymers

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

Cyclic polylactide synthesis initiated by a lithium anthraquinoid: understanding the selectivity through DFT and diffusion NMR

Abstract: We present herein the application of a lithium anthraquinoid in the catalytic synthesis of cyclic PLA, showing that the aggregation plays a critical role in cyclic vs. linear selectivity.

Cited by 5 publications

References 76 publications

Rapid Online Analysis of Photopolymerization Kinetics and Molecular Weight Using Diffusion NMR

Rapid Online Analysis of Photopolymerization Kinetics and Molecular Weight Using Diffusion NMR

Sustainable Polymers: Our Evolving Understanding

Lithium anthraquinoids as catalysts in the ROP of lactide and caprolactone into cyclic polymers

Contact Info

Product

Resources

About