- Heterobimetallic rare earth metal-zinc catalysts for reactions of epoxides and CO2under ambient conditions
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Four homodinuclear rare earth metal (RE) complexes1-4bearing a multidentate diglycolamine-bridged bis(phenolate) ligand were synthesized. In addition, seven heterobimetallic RE-Zn complexes5-11were prepared through a one-pot strategy. In these heterobimetallic complexes, two RE centers are bridged by either Zn(OAc)2or Zn(OBn)2moieties. All complexes were characterized by single crystal X-ray diffraction, elemental analysis, IR spectroscopy, and multinuclear NMR spectroscopy (in the case of diamagnetic complexes1,4,7and11). Moreover, the multi-nuclear structures of complexes4and11in solution were also studied by1H DOSY spectroscopy. These complexes were applied in catalyzing the coupling reaction of carbon dioxide (CO2) with epoxides. Zn(OAc)2- and Zn(OBn)2-bridged heterobimetallic complexes showed comparable catalytic activities under ambient conditions and were more active than monometallic RE complexes. Significant synergistic effect in heterobimetallic complexes is observed. Mono-substituted epoxides were converted into cyclic carbonates under 1 atm CO2at 25 °C in 88-96% yields, whereas di-substituted epoxides reacted under 1 atm CO2at higher temperatures in 40-80% yields.
- Yin, Kuan,Hua, Linyan,Qu, Liye,Yao, Quanyou,Wang, Yaorong,Yuan, Dan,You, Hongpeng,Yao, Yingming
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- Lactide cyclopolymerization by an alumatrane-inspired catalyst
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A new catalyst for the ring-expansion polymerization of lactide to cyclic poly(lactic acid) was investigated. Catalyst 1(alumatrane-inspired catalyst, (N,N-bis(3,5-di-tert-butyl-2-benzyloxy)-2-(2-aminoethoxy)ethoxy)aluminum) was active for the polymerizat
- Weil, Jonathan,Mathers, Robert T.,Getzler, Yutan D.Y.L.
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- Vanadium complexes with multidentate amine bisphenols
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The reaction of VO(acac)2 (acac- = acetyl acetonate) with tripodal glycine bisphenol H3L1 under an ambient atmosphere yields a hexacoordinated vanadium(iv) complex [V(acac)(L 1)] (1). The corresponding reactions with tripodal 2-propanolamine bisphenol H3L2 and potentially pentadentate ethoxyethanolamine bisphenol H3L3 lead to the oxidation of the metal centre and formation of mononuclear oxovanadium(v) complexes [VO(L2)] (2) and [VO(L3)] (3), respectively. Alternatively, these latter two complexes can be prepared using VOSO 4·5H2O or VO(OPr)3 as a precursor. The CV of 1 in an ACN solution shows a reversible one-electron process at E 1/2 = +1.18 V, whereas 2 and 3 have an irreversible redox response at -1.6 V and -1.2 V, respectively. Complexes 2 and 3 show moderate activity in the epoxidation of cis-cyclooctene by tert-BuOOH at 50 °C.
- Haenninen,Peuronen,Damlin,Tyystjaervi,Kivelae,Lehtonen
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- Synthesis, Characterization, and Catalytic Study of Amine-Bridged Bis(phenolato) Co(II) and Co(II/III)-M(I) Complexes (M = K or Na)
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Co(II) complexes 1-3 bearing amine-bridged bis(phenolato) complexes have been synthesized through reactions of bis(phenols) with CoCl2 or Co(OAc)2. Oxidation of the Co(II) complex with air resulted in partial oxidation, generating mixed valence Co(II/III)
- He, Xinyi,Wang, Yanwei,Yuan, Dan,You, Hongpeng,Yao, Yingming
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supporting information
p. 11521 - 11529
(2021/08/03)
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- Heteronuclear metal complex and preparation method of cyclic carbonate catalyzed by heteronuclear metal complex
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The invention discloses a method for preparing cyclic carbonate by converting carbon dioxide and an epoxide compound under the effect of a catalyst, and belongs to the technical field of organic compound preparation. According to the method disclosed by the invention, the catalyst is easy to prepare, the yield is high, reaction conditions are mild, and high-selectivity conversion of the carbon dioxide and the epoxide compound can be realized at ambient temperature and under normal pressure, so that the cyclic carbonate compound is synthesized, and universality of a substrate is wide. The technical scheme is as the follows that a diethylene glycol amino bridged diaryloxy rare earth-benzyloxy magnesium heteronuclear metal complex and a quaternary ammonium salt are used as a catalytic system,and the carbon dioxide and the epoxide compound are used as reactants to synthesize the cyclic carbonate compound.
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Paragraph 0044; 0045; 0046
(2019/05/15)
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