The compound [Ru(CN(t)Bu)4(Cl)2], 1, reacts with I2, yielding the halogen-bonded (XB) 1D species {[Ru(CN(t)Bu)4(I)2]·I2}n, (2·I2)n, whose building block contains I(-) ligands in place of Cl(-) ligands, even though no suitable redox agent is present in solution. Some isolated solid-state intermediates, such as {[Ru(CN(t)Bu)4(Cl)2]·2I2}n, (1·2I2)n, and {[Ru(CN(t)Bu)4(Cl)(I)]·3I2}n, (3·3I2)n, indicate the stepwise substitution of the two trans-halide ligands in 1, showing that end-on-coordinated trihalides play a key role in the process. In particular, the formation of ClI2(-) triggers electron transfer, possibly followed by an inverted coordination of the triatomic species through the external iodine atom. This allows I-Cl separation, as corroborated by Raman spectra. The process through XB intermediates corresponds to reduction of one iodine atom combined with the oxidation of one coordinated chloride ligand to give the corresponding zerovalent atom of I-Cl. This redox process, explored by density functional theory calculations (B97D/6-31+G(d,p)/SDD (for I and Ru atoms)), is apparently counterintuitive with respect to the known behavior of the corresponding free halogen systems, which favor iodide oxidation by Cl2. On the other hand, similar energy barriers are found for the metal-assisted process and require a supply of energy to be passed. In this respect, the control of the temperature is fundamental in combination with the favorable crystallizations of the various solid-state products. As an important conclusion, trihalogens, as XB adducts, are not static in nature but are able to undergo dynamic inner electron transfers consistently with implicit redox chemistry.

The asymmetric unit of the title compound, C3H5N2 +·C6H2N3O7 −·C3H4N2·H2O or H(C3H4N2)2 +·C6H2N3O7 −·H2O, contains a diimidazolium cationic unit, one picrate anion and one mol­ecule of water. In the crystal, the components are connected by N—H⋯O, N—H⋯N and O—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (001). In addition, weak inter­molecular C—H⋯O hydrogen bonds lead to the formation of a three-dimensional network featuring R 5 5(19) rings.

Nymphs and adults of several spittlebug (Hemiptera: Cercopidae) species are key pests of forage brachiariagrasses (Brachiaria spp.) in tropical America. To support current breeding programs, a series of experiments aimed at characterizing the mechanisms of resistance to adult feeding damage were carried out. Five genotypes were used: two susceptible checks (CIAT 0606 and CIAT 0654) and three nymph-resistant genotypes (CIAT 36087, CIAT 6294, and SX01NO/0102). Test insects were Aeneolamia varia (F.), A. reducta (Lallemand), and Zulia carbonaria (Lallemand). The nymph-resistant genotypes showed tolerance to all spittlebug species tested. Tolerance in these genotypes can be classified as only moderate given the extent of losses (60-80%) caused by both female and male adults. None of the nymph-resistant genotypes had antibiotic effects on adults feeding on foliage. The results also indicated that antixenosis for feeding is not a plausible explanation for lower damage scores and less biomass losses in resistant genotypes. The fact that adult longevity (usually 8 d) was not affected when the adults were forced to feed on roots of a genotype with strong antibiotic resistance to nymphs is regarded as additional evidence that resistances to nymphs and to adults in Brachiaria are largely independent.

In the title compound, C14H11NO2, the benzene rings are inclined to each other with a dihedral angle between their mean planes of 8.42 (6)°. The nitro group is almost coplanar with the attached benzene ring but is rotated about the C-N bond by 5.84 (12)°. This redetermination results in a crystal structure with significantly higher precision than the original determination [Hertel & Romer (1931). Z. Kristallogr. 76, 467-469], and the intermolecular interactions have been established. In the crystal structure, molecules are linked by C-HO hydrogen bonds to generate C(5), C(13) and edge-fused R33(28) rings

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