A Defective Linear Pentachromium Complex for the Enhanced Catalysis of the Cycloaddition of CO_2 with Propylene Oxide

Based on the ligand(2,7-bis(α-pyrimidylamino)-1,8-naphthyridine(H2 bpmany)), a linear pentachromium complex [Cr_5(μ_5-bpmany)_4Cl_2]PF_6(1, μ5-bpmany = 2,7-bis(a-pyrimidylamino)-1,8-naphthyridine) was synthesized. The crystal structure of compound 1 has been characterized by X-ray crystallography. Interestingly, one metal atom in the center is missing in this linear chain, leading to the defective pentachromium metal string structure which is similar with the reported complex [Cr_5(μ_5-dpznda)_4Cl_2](2, dpznda = N~2,N~7-di(pyrazin-2-yl)-1,8-naphthyridine-2,7-diamine). The central Cr(Ⅲ) ion of 1 is eight-coordinated and is also rare in the chromium complex. The reaction of carbon dioxide with propylene oxide that generates propylene carbonate(PC) when catalyzed by [Cr_5(μ_5-bpmany)_4Cl_2]PF_6 was investigated. Different reaction conditions including temperature and pressure were studied to optimize the reaction conditions.     

二氧化碳与环氧化物共聚催化剂研究进展

二氧化碳是主要的温室气体,也是最丰富的C1资源.利用二氧化碳与环氧化物共聚生成可生物降解的聚碳酸酯是目前研究的热点之一.就目前的研究情况而言,二氧化碳与环氧化物共聚反应存在的主要问题是催化效率低、催化剂成本高、反应条件苛刻、共聚物产率较低以及催化剂分离复杂等.我们分类综述了二氧化碳与环氧化物共聚的新型催化体系,并探讨了各类催化体系的优缺点,对二氧化碳的资源化利用具有重要的应用价值.