Three novel and various isopolymolybdate-based hybrids built from the carboxyl oxygen atoms of in situ ligands: substituent-tuned assembly, architectures and properties.

By changing the N-donor groups of benzonitrile-based reactants, three novel isopolymolybdate-based compounds, [Cu(DBIBA)3][δ-HMo8O26] (1), [Cu(H2O)(DIBA)(DIBAH)(γ-HMo8O26)]·2H2O (2), and [CuI(DTBA)(Mo2O6)] (3) (HDBIBA = 3,5-di(benzoimidazol-1-yl)benzoic acid, HDIBA = 3,5-di(1H-imidazol-1-yl)benzoic acid and HDTBA = 3,5-di(1,2,4-triazol-1-yl)benzoic acid) were synthesized, in which the benzene carboxylate-based ligands DBIBA, DIBA and DTBA were in situ transformed from the benzonitrile-based ligands under hydrothermal conditions. Selecting benzoimidazol as the N-donor group, compound 1 with a 3D (6, 8)-connected framework is constructed from {Cu3(DBIBA)3} hexagonal ring building units and [δ-Mo8O26]4- polyoxoanions. Replacing the benzoimidazol with the imidazol group, a 3D (3, 4, 6)-connected framework 2 containing two types of {(γ-Mo8O26)(DIBA)2} building blocks was obtained. When the triazol groups are introduced, compound 3 displays a 3D framework, which is constructed from {(Mo4O13)(DTBA)2}n chains bridged by CuI atoms. It is interesting to note that the carboxyl oxygen atoms from the in situ ligands participate in the construction of isopolymolybdates in compounds 2 and 3. In addition, the various N-donor groups of in situ ligands show a great effect on the oxidation state of copper ions, the novel polymolybdate unit and the final architectures of the title compounds. The electrochemical properties and photocatalytic activities of compounds 1-3 were investigated herein.

3-Methylthiopropionic Acid of Rhizoctonia solani AG-3 and Its Role in the Pathogenicity of the Fungus.

Studies were conducted to determine the role of 3-methylthioproprionic acid (MTPA) in the pathogenicity of potato stem canker, Rhizoctonia solani, and the concentrations required to inhibit growth of R. solani under laboratory and plant house-based conditions. The experiments were laid out in a completely randomized design with five treatments and five replications. The treatments were 0, 1, 2, 4, and 8 mM concentrations of MTPA. The purified toxin exhibited maximal activity at pH 2.5 and 30°C. MTPA at 1, 2, 4, and 8 mM levels reduced plant height, chlorophyll content, haulm fresh weight, number of stolons, canopy development, and tuber weight of potato plants, as compared to the control. MTPA significantly affected mycelial growth with 8 mM causing the highest infection. The potato seedlings treated with MTPA concentrations of 1.0-8.0 mM induced necrosis of up to 80% of root system area. Cankers were resulted from the injection of potato seedling stems with 8.0 mM MTPA. The results showed the disappearance of cell membrane, rough mitochondrial and cell walls, change of the shape of chloroplasts, and swollen endoplasmic reticulum. Seventy-six (76) hours after toxin treatment, cell contents were completely broken, cytoplasm dissolved, and more chromatin were seen in the nucleus. The results suggested that high levels of the toxin concentration caused cell membrane and cytoplasm fracture. The integrity of cellular structure was destroyed by the phytotoxin. The concentrations of the phytotoxin were significantly correlated with pathogenicity and caused damage to the cell membrane of potato stem base tissue.