Search

[Ni(hmp)(MeOH)Br]4 ⋅ 2H2O has been prepared by the reaction of 2-hydroxymethylpyridine with NiBr2 ⋅ 3H2O and characterized by IR, elemental analysis, powder X-ray diffraction, thermogravimetric analyses, magnetic measurements, and single crystal X-ray diffraction. The crystal structure shows two independent [Ni(hmp)(MeOH)Br]4 molecules in the asymmetric unit and [Ni4O4]4+ cubane-type cores. Each octahedral Ni(II) is bridged by four μ3-CH2O − fragments from four hmp − ligands. Magnetic studies show that ferromagnetic coupling gives an S = 4 ground state with significant magnetoanisotropy, and the parameters are J 1 = 8.56, J 2 = 2.28, D = −0.65 cm−1, and g ≈ 2.13.

A novel bilayered coordination polymer with nanoporous channels [Ni3(bix)3(PTCO)2 (H2O)4·6H2O]n (1) has been synthesized and the permanent porosity of (1) is confirmed by N2 adsorption isotherm measurement.

Three novel 3D metal–organic frameworks, [Co2(butca)(o-bix)2·8H2O]n (1), [Co2(butca)(m-bix)2·2H2O]n (2) and [Co2(butca)(p-bix)2·3H2O]n (3) (butca = 1,2,3,4-butane-tetracarboxylic acid; o-bix = 1,2-bis(imidazol-1-ylmethyl)-benzene; m-bix = 1,3-bis(imidazol-1-ylmethyl)-benzene; and p-bix = 1,4-bis(imidazol-1-ylmethyl)-benzene), have been successfully synthesized from a 2D layer compound [Co2(butca)(H2O)5·2H2O]n (0) employing a three isomer pillars insertion reaction, and their structures were determined by single-crystal X-ray diffraction studies. Complexes 1 and 2 are isostructural. Interestingly, there exist metal-bix double-helical chains in these two 3D frameworks, which are arranged left- and right-handed alternately. Different from 1 and 2 which have only one coordination model, Co atoms in 3 have two types of different coordination enviroments. The Co1 ions are exclusively bridged by cis-bix ligands to give one 26-number ring through spontaneous resolution. At the same time, the Co2 ions are wholely connected with tran-bix ligands to form a 1-D zigzag chain. Moreover, the relationship between a 2D layer structure and 3D metal–organic frameworks based on the pillared-layer motifs is discussed. This work has significant potential for the study of crystal engineering of transition metal coordination networks.

The AP2/EREBP transcription factors play important roles in plant development and in the responses of plants to biotic and abiotic stresses. All members of the EREBP subfamily described to date are from dicotyledonous plants. In this paper, we describe the cloning and characterization of a rice gene, OsEBP-89, encoding a protein 326 amino acids long with a typical EREBP domain; this is the first report of an EREBP transcription factor in a monocotyledonous plant. Except for the EREBP domain, the OsEBP-89 protein does not have substantial sequence similarities to other members of the subfamily. The DNA-binding activity of the EREBP domain was confirmed by electrophoretic mobility-shift assays. An activation domain rich in acidic amino acids was identified by using a yeast one-hybrid system. Two putative nuclear-localization signals were also identified. The results of northern blot hybridization experiments showed that the transcript of the OsEBP-89 gene accumulates primarily in immature seeds, roots, and leaves (low levels). More detailed information about the pattern of OsEBP-89 gene expression was obtained by histochemical studies of transgenic rice plants carrying an OsEBP-89 5'/GUS reporter gene. The reporter gene was expressed in the endosperm starting at 7 days after pollination and in the intercalary meristem of plants. Expression of OsEBP-89 was induced in roots of rice seedlings by treatment with ACC, NaCl, or 2,4-D. Two cis-acting elements, an endosperm motif and a primary PERE, are present upstream of the OsEBP-89 coding region and may be involved in regulating its expression. Collectively, these results suggest that the OsEBP-89 gene is a new member of the EREBP subfamily and may be involved in ethylene-dependent seed maturation and shoot development of rice.