Synthesis and characterization of a new binuclear cobalt complex containing μ-acetamidino-μ-amido-μ-nitrito-bridged groups via an intramolecular condensation

Condensation of coordinated acetonitrile and one of the amine ligands in [(NH₃)₄Co·μ(NH₂,NO₂)·Co(NH₃)₄](CF₃SO₃)₄. H₂O (2c) results in the formation of a bridging acetamidino group. It is assumed that an intramolecular reaction occurred in which a coordinated amido ligand attack the substituted acetonitrile group to yield the third bridge. In this process the amido and acetonitrile groups which are coordinated to adjacent cobalt centers should bear a syn relationship. Synthesis and characterization of [(NH₃)₃Co·μ(CH₃C(NH)₂,NH₂,NO₂)·Co(NH₃)₃](CF₃SO₃)₃ (5) is reported here.     

抗气蚀聚氨酯涂层的研究进展

随着水轮机和螺旋桨等过流件的尺寸和转速不断提高,气蚀损坏问题更加突出,因此易施工涂覆且便于设计调控的聚氨酯涂层始终是耐气蚀领域的研究热点。系统回顾了聚氨酯材料在气蚀防护领域的研究发展历程,深刻指出了这类材料作为耐气蚀涂层使用时存在的突出问题,例如耐水性、附着力、机械性能、耐磨性能和防污能力等较差,系统分析了这些因素导致涂层损坏失效的机理。针对上述问题,重点根据聚氨酯独特的分子结构,分别从表面能、电负性、化学键合、接枝改性、添加功能填料等方面,提出了改善聚氨酯涂层在复杂工况下应用性的解决办法。最后,鉴于我国对能够在海洋等苛刻环境中长期稳定服役的高性能气蚀防护涂层的急迫需求,对发展以自愈合聚氨酯为代表的集防污抗气蚀耐磨损自修复等功能于一体的新型聚氨酯材料进行了展望。