Synthesis of guanidinophosphazene superbase for the facile preparation of high molecular weight polysiloxane under mild conditions

Duan, Wensheng; Li, Zhongwei; Yang, Zhizhou; He, Fuyan; Chen, Shisen; Qiao, Chuanling; Yao, Jinshui; Zhang, Changbin; Zhao, Hui; Li, Mei; Yang, Guihua

doi:10.1039/d2py01294d

Cited by 4 publications

(1 citation statement)

References 46 publications

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“…Another facet of modern organocatalysis is the development of polyfunctional catalysts. In this regard, the presence of a superbasic site in the catalyst is often required [ 146 , 147 , 148 , 149 , 150 ]. In addition to catalysis, recent applications in the field of material science [ 151 , 152 , 153 ], and for carbon dioxide capture and activation [ 154 , 155 , 156 , 157 , 158 , 159 , 160 ], seem to be promising.…”

Section: Overview and Prospectsmentioning

confidence: 99%

Strong Bases and beyond: The Prominent Contribution of Neutral Push–Pull Organic Molecules towards Superbases in the Gas Phase

Raczyńska,

Gal,

Maria

2024

IJMS

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In this review, the principles of gas-phase proton basicity measurements and theoretical calculations are recalled as a reminder of how the basicity PA/GB scale, based on Brønsted–Lowry theory, was constructed in the gas-phase (PA—proton affinity and/or GB—gas-phase basicity in the enthalpy and Gibbs energy scale, respectively). The origins of exceptionally strong gas-phase basicity of some organic nitrogen bases containing N-sp3 (amines), N-sp2 (imines, amidines, guanidines, polyguanides, phosphazenes), and N-sp (nitriles) are rationalized. In particular, the role of push–pull nitrogen bases in the development of the gas-phase basicity in the superbasicity region is emphasized. Some reasons for the difficulties in measurements for poly-functional nitrogen bases are highlighted. Various structural phenomena being in relation with gas-phase acid–base equilibria that should be considered in quantum-chemical calculations of PA/GB parameters are discussed. The preparation methods for strong organic push–pull bases containing a N-sp2 site of protonation are briefly reviewed. Finally, recent trends in research on neutral organic superbases, leaning toward catalytic and other remarkable applications, are underlined.

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Section: Overview and Prospectsmentioning

confidence: 99%

Strong Bases and beyond: The Prominent Contribution of Neutral Push–Pull Organic Molecules towards Superbases in the Gas Phase

Raczyńska,

Gal,

Maria

2024

IJMS

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Highly Active and Stereoselective Ring‐Opening Polymerization of Racemic Lactide Over HTGCP Catalysts

Mi,

Li,

et al. 2024

J of Applied Polymer Sci

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Despite the extraordinary success has been achieved in metal catalyst‐promoted stereoselective ring‐opening polymerization (ROP) of rac‐lactide (rac‐LA), well‐controlled stereoselective rac‐LA ROP by organic catalyst still remains a scientific challenge. In this study, we showcase the remarkable ability of the phosphazene base 2,2,4,4,6,6‐hexa(tetramethyl‐guanidyl)‐1,3,5,2λ5,4λ5,6λ5‐cyclictri(phosphazene) (HTGCP) to facilitate the stereoselective ROP of rac‐LA at low temperatures, yielding isotactic stereoblock poly (lactic acid) (PLA) with a stereoselectivity index (Pm) up to 0.86. Furthermore, by harnessing the synergy between HTGCP and a (thio)urea, both high stereoselectivity (Pm up to 0.85) and remarkable catalytic activity (> 99% monomer conversion within an hour) can be achieved at ambient temperature. Notably, upon decreasing the temperature to −20°C, an even higher degree of regularity is attained (Pm up to 0.91). The direct linear correlation between molecular weights (Mn), monomer conversions, and the narrow dispersity (Đ) of the resulting polymers, coupled with their high end‐group fidelity, underscores the meticulous control exerted over the polymerization. Based on these findings, we propose that the chain end control mechanism underlies the synthesis of isotactic stereoblock PLA from rac‐LA in the presence of HTGCP, offering a novel and efficient pathway to produce high‐performance PLA materials.

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Synthesis of Functionalized PDMS Fluids by Linear Chlorinated Phosphazene Acid Catalyst

Jin,

Zhang,

Yang

et al. 2024

Silicon

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Synthesis of guanidinophosphazene superbase for the facile preparation of high molecular weight polysiloxane under mild conditions

Cited by 4 publications

References 46 publications

Strong Bases and beyond: The Prominent Contribution of Neutral Push–Pull Organic Molecules towards Superbases in the Gas Phase

Strong Bases and beyond: The Prominent Contribution of Neutral Push–Pull Organic Molecules towards Superbases in the Gas Phase

Highly Active and Stereoselective Ring‐Opening Polymerization of Racemic Lactide Over HTGCP Catalysts

Synthesis of Functionalized PDMS Fluids by Linear Chlorinated Phosphazene Acid Catalyst

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