Ring-Opening Isomerization: Relationship between Discrete Molecular Architectures and Coordination Polymers

School of Chemistry and Chemical Engineering, Sun Yat-Sen University
â—‹Cheng-Yong Su Zhi-Min Liu Mei Pan

The existence of supramolecular isomerism in polymeric structures, which differ not by the building blocks but rather by the arrangement of the building blocks, has received increasing attention recently. Several examples of structural isomerism, conformational isomerism and topological isomerism have appeared in the literature. In contrast, discussions of supramolecular isomers, consisting of the closed and the polymeric isomers, have appeared only recently. Zaworotko1 demonstrated such isomerism for the case of a discrete molecular hexagon and a polymeric zigzag chain. Another example reported by James2, where the coordination polymer [M2L3]n was obtained from the [M2L3] precursor. It appears that the conversion from the closed structure to the polymeric one inevitably accompanies at least one ring opening. Therefore, we prefer to term this interconversion process as ring-opening isomerism.3 Here, we would like to introduce some interesting examples which show formation of polymeric structures from the discrete ring or cage precursors. References: (1) Zaworotko, M. J. etc J. Am. Chem. Soc. 2002, 124, 9990; (2) James, S. L. etc Chem. Eur. J. 2001, 7, 2644. (3) Su, C.-Y. etc Inorg. Chem. 2003, 42, 5685. Supported by the NNSFC (No. 20525310)