一系列吡啶基双(脲)配体在金属离子(金属凝胶),尤其是铜(II)和银(I)的存在下形成超分子凝胶。通过流变仪和扫描电子显微镜对凝胶进行了表征,并研究了金属离子对凝胶强度和形态的影响。金属诱导的凝胶化与脲-脲和脲-吡啶基氢键相互作用之间的竞争有关。从这些凝胶中生长出来的晶体揭示了这些系统的大量结构信息,这些信息可通过其异凝胶的粉末 X 射线衍射数据与凝胶结构联系起来。
A New Series of Cu<sup>II</sup> Coordination Polymers Derived from Bis-pyridyl-bis-urea Ligands and Various Dicarboxylates and Their Role in Methanolysis of Epoxide Ring-Opening Catalysis
作者:Subhabrata Banerjee、Dhurjati Prasad Kumar、Sabyasachi Bandyopadhay、N. N. Adarsh、Parthasarathi Dastidar
DOI:10.1021/cg3011037
日期:2012.11.7
A crystal engineering approach has been adopted in synthesizing six new mixed ligand based Cu-II coordination polymers (CPs) derived from two bis-pyridyl-bis-urea ligands, namely, N,N'-bis-(3-pyridyl)ethylene-bis-urea (L1) and N,N'-bis-(3-pyridyl)propylene-bis-urea (L2), and various dicarboxylates. The single crystal structures of the coordination polymers displayed diverse supramolecular architectures such as a one-dimensional (1D) chain, 1D-looped chain, and two-dimensional grid. Although none of them displayed an open framework structure, which is believed to be conducive for heterogeneous catalysis, almost all of them showed moderate to excellent epoxide ring opening catalysis. Powder X-ray. diffraction indicated structural changes/degradation of the CPs, which might be generating substrate accessible Cu-II species that presumably acted as the catalyst.
A “Compartmental” Borromean Weave Coordination Polymer Exhibiting Saturated Hydrogen Bonding to Anions and Water Cluster Inclusion
作者:Peter Byrne、Gareth O. Lloyd、Nigel Clarke、Jonathan W. Steed