Triazolyl鈥揃ased Copper鈥揗olybdate Hybrids: From Composition Space Diagram to Magnetism and Catalytic Performance

详细信息    查看全文

• 作者：Ganna A. Senchyk ; Andrey B. Lysenko ; Artem A. Babaryk ; Eduard B. Rusanov ; Harald Krautscheid ; Patr铆cia Neves ; Anabela A. Valente ; Isabel S. Gon莽alves ; Karl W. Kr盲mer ; Shi-Xia Liu ; Silvio Decurtins ; Konstantin V. Domasevitch
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：October 6, 2014
• 年：2014
• 卷：53
• 期：19
• 页码：10112-10121
• 全文大小：628K
• ISSN：1520-510X

文摘

The multicomponent mixed-metal Cu^II/Mo^VI oxides/1,3-bis(1,2,4-triazol-4-yl)adamantane (tr₂ad) system was thoroughly studied employing a compositional diagram approach. The concept allowed us to prepare three layered copper鈥搈olybdate hybrid solids [Cu^II₂(tr₂ad)₄](Mo₈O₂₆) (1), [Cu₄^II(渭₄-O)(tr₂ad)₂(MoO₄)₃]路7.5H₂O (2), and [Cu^I₂(tr₂ad)₂](Mo₂O₇)路H₂O (3), and to elucidate the relationship between initial reagent concentration/stoichiometry and the stability of the resultant structural motifs. Compounds 1 and 2 were found to dominate throughout a wide crystallization range of the concentration triangle, whereas compound 3 was formed by redox processes in the narrow crystallization area having a high excess of Cu(OAc)₂路H₂O. Independent experiments carried out with Cu(OAc)₂ and (NH₄)₆Mo₇O₂₄ in the absence of tr₂ad, under the same conditions, revealed the formation of low-valent and bimetallic oxides, including Cu₂O, MoO₂, Cu(Mo₃O₁₀)路H₂O, and Cu₃(MoO₄)₂(OH)₂. Compounds 1 and 2 show high thermal and chemical stability as examined as catalysts in the epoxidation of cis-cyclooctene and the oxidation of benzyl alcohol (BzOH) with different types of oxidants. The oxidation reaction of BzOH using tert-butyl hydroperoxide (TBHP) as the oxidant, in the presence of 1 or 2, led to benzaldehyde and benzoic acid (PhCO₂H), with the latter being formed in up to 90% yield at 24 h. The results suggest that 1 and 2 may be favorable heterogeneous catalysts for the synthesis of PhCO₂H. Whereas compound 1 only reveals a weak ferromagnetic coupling between neighboring Cu^II centers (J = 0.41 cm^鈥?), compound 2 shows distinct intracluster antiferromagnetic exchange interactions (J = 鈭?9.9 cm^鈥?, J鈥?= 鈭?5.7 cm^鈥?), which consequently results in a diamagnetic ground state.