Coordination Polymers and Cage-Containing Frameworks in Uranyl Ion Complexes with rac- and (1R,2R)-trans-1,2-Cyclohexanedicarboxylates: Consequences of Chirality

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• 作者：Pierre ThuéryJack Harrowfield
• 刊名：Inorganic Chemistry
• 出版年：2017
• 出版时间：February 6, 2017
• 年：2017
• 卷：56
• 期：3
• 页码：1455-1469
• 全文大小：1059K
• ISSN：1520-510X

文摘

Racemic and enantiopure (1R,2R) forms of trans-1,2-cyclohexanedicarboxylic acid (H₂chdc and R-H₂chdc, respectively) have been used in the synthesis of a series of 13 uranyl ion complexes, all obtained under solvo-hydrothermal conditions and in the presence of additional metal cations and/or N-donor ligands. While the homometallic complex [UO₂(R-chdc)] (1) was only obtained with the enantiopure ligand, complexes [UO₂(chdc)(THF)] (2), [UO₂(chdc)(DMF)] (3), and [UO₂(chdc)(NMP)] (4), with a coordinated solvent molecule, were obtained from the racemic form only; all crystallize as two-dimensional (2D) assemblies. The two complexes [UO₂(chdc)(bipy)](5) and [UO₂(R-chdc)(bipy)] (6), where bipy is 2,2′-bipyridine, are isomorphous since 5 crystallizes as a racemic conglomerate; they are both one-dimensional (1D) homochiral, helical polymers. The heterometallic complexes [UO₂Cu(chdc)₂(bipy)(H₂O)]·H₂O (7) and [UO₂Cu(R-chdc)₂(bipy)]·3H₂O (8) crystallize as a 1D or a 2D species, respectively, while [UO₂Cd(R-chdc)₂(H₂O)₂]·H₂O (9) displays a 2D arrangement with the unusual Cairo pentagonal tiling topology. The four complexes [(UO₂)₂Na₂(chdc)₃(H₂O)₂] (10), [(UO₂)₂Ag₂(chdc)₃(H₂O)₂] (11), [(UO₂)₂Na₂(R-chdc)₃(H₂O)₂] (12), and [(UO₂)₂Pb(R-chdc)₃(H₂O)₄] (13) are closely related, all of them containing tetranuclear, pseudotetrahedral [(UO₂)₄(chdc/R-chdc)₆]^4– cage motifs, that are assembled into a three-dimensional (3D) framework by bridging counterions (Na⁺, Ag⁺, or Pb²⁺). These cages define a new pathway to assembly of such species based on the unique coordination geometry of uranyl ion, differing from the widely exploited use of octahedral metal ions.