Alternating copolymerization of carbon dioxide and propylene oxide by single-component cobalt salen complexes with various axial group

Polymer ◽  
2009 ◽  
Vol 50 (21) ◽  
pp. 5071-5075 ◽  
Author(s):  
Binyuan Liu ◽  
Xin Zhao ◽  
Hongfei Guo ◽  
Yanhao Gao ◽  
Min Yang ◽  
...  
2021 ◽  
Vol 12 (12) ◽  
pp. 1776-1786
Author(s):  
Zhou Wang ◽  
Ying Mu

Stereoregular poly(propylene carbonate)s and poly(propylene succinate-block-carbonate)s were synthesized with new chiral salenCo(iii) catalysts carrying bulky substituents.


2020 ◽  
Author(s):  
Xing-Hong Zhang

Metal-free synthesis of fully alternating polycarbonates from carbon dioxide (CO2) and epoxides is highly desired but a huge challenge. Here, we disclose the combination of tertiary amines with trialkyl boranes for completely alternating copolymerization of CO2 with epoxides. Triethylamine (TEA) pairing with triethyl borane (TEB), the simplest catalyst for the copolymerization of CO2 and propylene oxide (PO), afforded fully alternating poly(propylene carbonate) (PPC) with a turnover frequency (TOF) of 54 h-1 at 60 oC. Remarkably, diamine such as, N,N,N',N'-tetraethylethylenediamine (TEED) and triamine such as N,N,N',N'',N''-pentamethyldiethylene triamine (PMDETA) pairing with TEB exhibited improved the copolymer selectivity of up to 99%. Supplementally, the effect of trialkylborane structure on the copolymerization were also investigated. Moreover, PPCs prepared from these tertiary amines/ trialkyl boranes Lewis pairs showed the head-to-tail diad content of around 80%. The number-average molecular weight of PPC was up to 56.0 kg/mol with narrow distribution (Đ =1.16) and could be easily adjusted by simply varying the feeding ratios. The 1H NMR spectra and MALDI-TOF-MS spectra suggest that both tertiary amine-activating CO2 and TEB-masked end anions cooperatively promote the fully alternating CO2/epoxide copolymerization. This work provides an organocatalytic platform for well-defined CO2/epoxide copolymers using simple small molecules with high atomic utilization.<br>


2013 ◽  
Vol 734-737 ◽  
pp. 2159-2162 ◽  
Author(s):  
Chong Wen Jiang ◽  
Chen Chen Zhao ◽  
Ke Yuan Zhou

Three salen complexes N,N'-bis(salicylidene)-1,2-phenylenediamino MⅢ Cl were prepared and employed for the copolymerization of carbon dioxide with propylene oxide. FT-IR and UV-Vis spectra confirmed the characteristic of metal salen complexes obtained. The central metal atoms in the salen complexes have great influence on the copolymerization of carbon dioxide with propylene oxide. The result shows that chromium metal is more effective to synthesize PPC copolymer. The structure of the resulting PPC was characterized by IR 1H NMR and GPC. 86.3% carbonate content of the PPC was achieved with chromium salen complexes.


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