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Thirteen crystal structures of copper(II) complexes with a series of dipicolylamine (DPA)-derived ligands, N-(2-methoxyethyl)-N,N-bis(2-pyridylmethyl)amine (L1), N-[2-(2-hydroxyethyloxy)ethyl]-N,N-bis(2-pyridylmethyl)amine (L2) and N-(3-methoxypropyl)-N,N-bis(2-pyridylmethyl)amine (L3), have been determined and the factors that control the coordination of the ether-oxygen atom of these ligands to the copper centre are discussed. Complexes that have +1 or +2 charges exhibit coordination of the ether-oxygen atom, whereas neutral complexes in which two anions are bound to the copper(II) centre tend to lose the oxygen coordination. Upon chelation of the oxygen atom, L3 forms a six-membered chelate ring with respect to the 3-aminopropyl ether moiety whereas L1 and L2 form a five-membered chelate. This difference, especially in the nitrate and bromide complexes, determines whether the ether-oxygen atom chelates to the metal centre to give a monocationic complex, or the second anion coordinates to the metal centre to form the ether-free, neutral complex. The terminal anchor hydroxy group of L2 facilitates the ether-oxygen coordination via a hydrogen bond interaction to the donor atom located trans to the aliphatic nitrogen atom in the basal plane. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Direct ion-exchange of monovalent copper ions into a ZSM-5-type zeolite was carried out using an aqueous solution of diammine–copper(i) ions, [Cu(NH₃)₂]+, to prepare a copper ion-exchanged ZSM-5 zeolite including only monovalent copper ions, and the effect of monovalent copper ions on the zeolite's adsorption properties for dinitrogen (N₂) was examined. Strangely enough, the reoxidation of monovalent copper-ion exchanged in ZSM-5 took place in the evacuation process at around 473 K. The changes in valence and structure of the exchanged copper-ions during the evacuation process and the interaction with N₂ molecules at room temperature have been investigated by using spectroscopic techniques such as X-ray absorption fine structure (XAFS), IR and photoemission spectroscopy, as well as by measurements of adsorption isotherms and adsorption heats. On the basis of X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses, it has become apparent that the Cu+ species exchanged in ZSM-5 zeolite is oxidized by water to form a divalent species having a CuO-like structure through heat-treatment in vacuo at 473 K. Further heat-treatment at temperatures above 673 K caused a reduction of the divalent species to a monovalent one that exhibits a pronounced adsorption feature for N₂ even at room temperature. XANES and photoemission data clearly indicated that the Cu+ species in an 873 K-treated CuZSM-5 sample has a three-coordinate structure with lattice oxygen atoms and interacts strongly with an N₂ molecule at room temperature. The strong interaction with N₂ was also verified through the adsorption heat and IR data: an initial adsorption energy of 85 kJ mol−1 and an absorption band at 2295 cm−1. A prominent feature of this system is that some of the adsorbed species survives after evacuation at 300 K, indicative of a strong interaction between N₂ and the three-coordinate copper ion.

Direct ion-exchange of monovalent copper ions into a ZSM-5-type zeolite was carried out using an aqueous solution of diammine–copperi ions, CuNH32, to prepare a copper ion-exchanged ZSM-5 zeolite including only monovalent copper ions, and the effect of monovalent copper ions on the zeolite's adsorption properties for dinitrogen N2 was examined. Strangely enough, the reoxidation of monovalent copper-ion exchanged in ZSM-5 took place in the evacuation process at around 473 K. The changes in valence and structure of the exchanged copper-ions during the evacuation process and the interaction with N2molecules at room temperature have been investigated by using spectroscopic techniques such as X-ray absorption fine structure XAFS, IR and photoemission spectroscopy, as well as by measurements of adsorption isotherms and adsorption heats. On the basis of X-ray absorption near-edge structure XANES and extended X-ray absorption fine structure EXAFS analyses, it has become apparent that the Cuspecies exchanged in ZSM-5 zeolite is oxidized by water to form a divalent species having a CuO-like structure through heat-treatment in vacuoat 473 K. Further heat-treatment at temperatures above 673 K caused a reduction of the divalent species to a monovalent one that exhibits a pronounced adsorption feature for N2even at room temperature. XANES and photoemission data clearly indicated that the Cuspecies in an 873 K-treated CuZSM-5 sample has a three-coordinate structure with lattice oxygen atoms and interacts strongly with an N2molecule at room temperature. The strong interaction with N2was also verified through the adsorption heat and IR data: an initial adsorption energy of 85 kJ mol−1and an absorption band at 2295 cm−1. A prominent feature of this system is that some of the adsorbed species survives after evacuation at 300 K, indicative of a strong interaction between N2and the three-coordinate copper ion.

Although some polymethoxyflavones possess several important biological properties, including neuroprotective, anticancer, and anti-inflammatory ones, sudachitin, a polymethoxyflavone from Citrus sudachi, has been little studied. In this study, we found that sudachitin inhibited nitric oxide production by suppressing the expression of inducible nitric oxide synthase in lipopolysaccharide-stimulated macrophages, indicating that sudachitin has an anti-inflammatory effect.