Anion-Directed Coordination Networks of a Flexible S-Pivot Ligand and Anion Exchange in the Solid State

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• 作者：Eunji Lee ; Huiyeong Ju ; Seulgi Kim ; Ki-Min Park ; Shim Sung Lee
• 刊名：Crystal Growth & Design
• 出版年：2015
• 出版时间：November 4, 2015
• 年：2015
• 卷：15
• 期：11
• 页码：5427-5436
• 全文大小：692K
• ISSN：1528-7505

文摘

Using an S-pivot joint flexible ligand bis(4-cyanobenzyl)sulfide (bcbs), three silver(I) complexes [Ag(bcbs)ClO₄]_n (1), [Ag₂(bcbs) (CF₃CO₂)₂]_n (2), and {[Ag₃(bcbs)₄](PF₆)₃路4CH₂Cl₂}_n (3) have been isolated. Configurations (鈥淰鈥?, 鈥淟鈥?, and 鈥淲鈥?shapes) of the bcbs ligand in 1鈥?b>3 can be tuned as a result of changing the anions of the silver(I) salts, which ultimately form a series of infinite low to high dimensional frameworks with different structures. The perchlorato compound 1 shows a stairway type 1-D ribbon structure, in which the anion acts as a monodentate terminal ligand. The bcbs ligand in 1 shows a gauche鈥揳nti arrangement, adopting an L-shape configuration. The 蟺鈥撓€ stacking interaction between adjacent ribbons in 1 yields a pseudo-2-D structure with a herringbone pattern. Compound 2 is composed of silver(I)鈥揵cbs helical channels, which are further interlinked via monodentate bridging CF₃CO₂^{鈥?/sup> ions forming a 3-D multichannel framework with a dmd topology. Unlike 1, the bcbs ligand in 2 shows an anti鈥揳nti arrangement, adopting a W-shape configuration. The corresponding PF₆鈥?/sup> complex 3 exhibits a 2-fold interpenetrated 3-D framework. The preferred anion-free structure in 3 presumably reflects the strong coordination of the donor set and the weak affinity of the PF₆鈥?/sup> toward the metal center. Similar to 1, the bcbs ligand in 3 adopts an L-shape configuration. In this work, the structural variations of the resulting coordination polymers are mainly associated with the diverse configurations of the flexible ligand, as well as the different coordination modes and abilities for the anions. Anion exchange accompanying an irreversible structural conversion from 2 or 3 to 1 was monitored in the crystalline state by IR and PXRD studies. AFM images and height profiles for the crystal surface before and after the anion-exchange were observed. On the basis of the above measurements, a mechanistic process from the 3-D structured 3 (PF₆鈥?/sup> form) to the 1-D structured 1 (ClO₄鈥?/sup> form) by the anion exchange was also proposed.}