On closer inspection : reviewing the debate on whether fish cooperate to inspect predators

This work was funded by an EASTBIO DTP scholarship to A. Li Veiros.Cooperative behaviours, which benefit a recipient, are widespread in the animal kingdom; yet their evolution is not straightforward. Reciprocity, i.e., cooperating with previously experienced cooperative partners, has been suggested to underly cooperation, but has been contested throughout the years. Once a textbook example of reciprocity was cooperative predator inspection, where one or several individuals leave their group to approach a potential threat. Each can at any point stop or retreat, increasing the risk for its partner. It was suggested that inspecting individuals follow a specific reciprocal strategy called tit-for-tat, i.e., cooperating on the first move and then copying the partner's last move. Numerous studies provide evidence to support the claim that fish cooperate to inspect predators, including three-spined sticklebacks (Gasterosteus aculeatus), guppies (Poecilia reticulata) and minnows (Phoxinus phoxinus). However, over the past few decades some scholars have expressed scepticism whether predator inspection is indeed a cooperative behaviour or rather a case of by-product mutualism, which describes behaviours that benefit a partner as a corollary of an otherwise selfish behaviour. For instance, it has been shown that pairs of fish moving in unfamiliar environments appear to coordinate movements even in the absence of predators. Many studies have also used coarse measures of overall approach rates towards predators rather than the fine-grained analyses necessary to infer tit-for-tat in cooperative inspections. Now is the time to return to the question of cooperative predator inspection with new tools and approaches to resolve a decades-old debate.Publisher PDFPeer reviewe

Indenylové sloučeniny s blokovanou hapticitou. Vliv silné intramolekulární interakce

A series of cyclopentadienyl and indenyl molybdenum(II) compounds with intramolecularly coordinated pyridine arms, including scorpionate-like species bearing two irreversibly coordinated arms on the indenyl core, were synthesized and characterized. All presented structural types were confirmed by X-ray diffraction analysis. Owing to the strong nucleophilicity of pyridine, the intramolecular interaction was found to be considerably stronger than that in analogous species bearing tertiary amines in the side chain. Although the starting compounds for the syntheses were isostructural, the reaction outcomes differed considerably. The cyclopentadienyl precursor gave a pentacoordinate η5:κN-compound, whereas the indenyl analogue produced a hexacoordinate species with the unprecedented η3:κN-coordination mode of the indenyl ligand and thus represents an unusual example of the so-called indenyl effect. The unusually high stability of the η3:κN-coordination compounds toward haptotropic rearrangement was clarified by theoretical calculations. As the strong intramolecular interaction prevented rotation of the indenyl moiety, it could not reach the conformation suitable for the η3 to η5 rearrangement. As a result, the low hapticity was effectively locked.Cyklopentadienylové a indenylové komplexy molybdenu s intramolekulárně coordinovaným pyridinem byly připraveny a charakterizovány spektroskopickými metodami. Strukturní typy, uvedené v této studii, byly potvrzeny RTG difrakční analýzou. Silná nukleofilicita pyridinu způsobuje silnou intramolekulární interakci postranního řetězce. Tato práce popisuje především nové η5:κN cyklopentadienylové a η3:κN indenylové komplexy. Silní intramolekulární interakce v těchto komplexech zabraňuje haptotropnímu přesmyku, který byl dříve podrobně popsán u analogů s nesubstituovaným indenylovým ligandem

Chemistry and catalytic performance of pyridyl-benzimidazole oxidomolybdenum(VI) compounds in (bio)olefin epoxidation

The chemistry and catalytic performance of the dichlorido complex [MoO2Cl2(pbim)] (1) [pbim = 2-(2-pyridyl)benzimidazole] in the epoxidation of olefins is reported. Complex 1 acts as a precatalyst and is more effective with tert-butyl-hydroperoxide (TBHP) as the oxidant than with aq. hydrogen peroxide: the cis-cyclooctene (Cy) reaction with TBHP gave 98 % epoxide yield at 70 degrees C/24 h. Catalyst characterization showed that 1 is transformed in situ to the oxidodiperoxido complex [MoO(O-2)(2)(pbim)] (2), with H2O2 and a hybrid molybdenum(VI) oxide solid formulated as [MoO3(pbim)] (3) with TBHP. The hybrid material 3 was prepared on a larger scale and explored for the epoxidation of the biorenewable olefins methyl oleate, methyl linoleate, and (R)-(+)-limonene. With TBHP as the oxidant, 3 acts as a source of soluble active species of the type 2. A practical method for recycling oxidodiperoxidomolybdenum(VI) catalysts for the Cy/TBHP reaction is demonstrated by using an ionic liquid as the solvent for the molecular catalyst 2.National funds through the Fundacao para a Ciencia e a Tecnologia (FCT) [POCI-01-0145-FEDER-007679, PD/BD/109666/2015]Ministerio da Educacao e Ciencia (MEC)Fundo Europeu de Desenvolvimento Regional (FEDER)European Union [PD/BD/109666/2015, SFRH/BPD/110530/2015, SFRH/BPD/108541/2015]Ministerio da Ciencia, Tecnologia e Ensino Superior (MCTES)European Social Fund through the program Programa Operacional Potencial Humano (POPH) of Quadro de Referencia Estrategica Nacional (QREN)info:eu-repo/semantics/publishedVersio

Synthesis and characterization of CpMo(CO)(3)(CH2-pC(6)H(4)-CO2CH3) and its inclusion compounds with methylated cyclodextrins. Applications in olefin epoxidation catalysis

The cyclopentadienyl molybdenum tricarbonyl complex CpMo(CO)(3)(CH2-pC(6)H(4)-CO2CH3) (1) (Cp = eta(5)-C5H5) and its 1:1 inclusion complexes with heptakis(2,6-di-O-methyl)-beta-cyclodextrin (1@DIMEB) and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (1@TRIMEB) were prepared and characterized by elemental and thermogravimetric analyses, powder X-ray diffraction, NMR, FT-IR and Raman spectroscopy. All three compounds were investigated as catalyst precursors for olefin epoxidation using cis-cyclooctene (Cy) as a model substrate, a reaction temperature of 55 degrees C, and different types of oxidants (tert-butylhydroperoxide in decane;(TBHPdec) or in water (TBHPaq), and aqueous hydrogen peroxide). With the aim of facilitating recycling of the homogeneous catalytic systems, different solvent mixtures were tested: biphasic liquid-liquid solvent systems [(water, glycerol, ionic liquid)-(n-hexane, alpha,alpha,alpha-trifluorotoluene (TFT), iso-butyl methyl ketone)], and in some cases no cosolvent was added. Excellent epoxide selectivity (100%) was observed for all tested catalytic systems. An example of an interesting catalytic system is that of 1@TRIMEB/TBHPaq/TFT/H2O since the catalyst can be easily separated in the form of an aqueous solution, by decantation, from the organic phase containing the reaction products and recycled. (C) 2013 Elsevier B.V. All rights reserved