1,2,4-Triazolyl-Carboxylate-Based MOFs Incorporating Triangular Cu(II)-Hydroxo Clusters: Topological Metamorphosis and Magnetism

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• 作者：Sergiy I. Vasylevs鈥檏yy ; Ganna A. Senchyk ; Andrey B. Lysenko ; Eduard B. Rusanov ; Alexander N. Chernega ; Julia Jezierska ; Harald Krautscheid ; Konstantin V. Domasevitch ; Andrew Ozarowski
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：April 7, 2014
• 年：2014
• 卷：53
• 期：7
• 页码：3642-3654
• 全文大小：766K
• 年卷期：v.53,no.7(April 7, 2014)
• ISSN：1520-510X

文摘

Bifunctional 1,2,4-triazole-carboxylate ligands, an achiral 1,2,4-triazol-4-yl-acetic acid (trgly-H) and a chiral (d)-2-(1,2,4-triazol-4-yl)-propionic acid (d-trala-H), derived from the corresponding 伪-amino acid precursors revealed unique binding abilities in the construction of Cu(II)-coordination polymers composing discrete triangular [Cu₃(渭₃-OH)] clusters. A related series of MOFs, [Cu₃(渭₃-OH)(trgly)₃(SO₄)]路2H₂O (1a), [Cu₃(渭₃-OH)(trgly)₃(H₂O)₃]SO₄路16H₂O (1b), Cu₃(渭₃-OH)(d-trala)₃(ClO₄)_0.5](ClO₄)_1.5路1.5H₂O (2), was prepared, and their crystal structures were determined by means of X-ray diffraction. Being singly deprotonated, the organic ligands act as multidentate 渭₃- or 渭₄-donors using tr and 鈭扖OO^{鈥?/sup> moieties. The generated [Cu₃(渭₃-OH)(tr)₃] cluster core is primarily supported by three [-N-N-] triazole heterocycles in a basal plane and tripodal-assisted 渭₃-anions (SO₄2鈥?/sup>: 1a; ClO₄鈥?/sup>: 2) capping the axial faces. The carboxylate groups join the units into either two-dimensional (2D) layer (1a, 2) or 3D zeolite-like networks (1b). Compound 1b represents the topology of 伪-Po (pcu: 412.63) and crystallizes in the noncentrosymmetric space group I4̅3m, in which the six-connected [Cu₃(渭₃-OH)] clusters and trgly self-assemble in an open-channel cubic array possessing 56% solvent-accessible volume. Upon slight thermal treatment (60 掳C), the structure irreversibly shrinks to the nonporous 2D motif 1a that belongs to a uninodal (3,6) network type. In structure 2 (space group R3₂), due to the [-N-N-] triazole and 1,3-bidentate carboxylate binding mode, each organic ligand bridges three metal clusters affording cross-linking of two adjacent layers with the same (3,6) topology. The resultant 3,9-c net is novel and can be categorized as two-nodal with point symbol {418.618}{42.6}₃. Spin frustration and antisymmetric exchange effects, resulting in abnormally low g values in the S = 1/2 states, were observed in the magnetic properties and the EPR spectra.}