Probing the Catalytically Active Species in POM‐Catalysed DNA‐Model Hydrolysis**

Phosphoester hydrolysis is an important chemical step in DNA repair. One archetypal molecular model of phosphoesters is para-nitrophenylphosphate (pNPP). It has been shown previously that the presence of molecular metal oxide [Mo7O24]6− may catalyse the hydrolysis of pNPP through the partial decomposition of polyoxomolybdate framework resulting in a [(PO4)2Mo5O15]6− product. Real-time monitoring of the catalytic system using electrospray ionisation mass spectrometry (ESI-MS) provided a glance into the species present in the reaction mixture and identification of potential catalytic candidates. Following up on the obtained spectrometric data, Density Functional Theory (DFT) calculations were carried out to characterise the hypothetical intermediate [Mo5O15(pNPP)2(H2O)6]6− that would be required to form under the hypothesised transformation. Surprisingly, our results point to the dimeric [Mo2O8]4− anion resulting from the decomposition of [Mo7O24]6− as the active catalytic species involved in the hydrolysis of pNPP rather than the originally assumed {Mo5O15} species. A similar study was carried out involving the same species but substituting Mo by W. The mechanism involving W species showed a higher barrier and less stable products in agreement with the non-catalytic effect found in experimental results

Chemical signal is in the blend : bases of plant-pollinator encounter in a highly specialized interaction

In several highly specialized plant-insect interactions, scent-mediated specificity of pollinator attraction is directed by the emission and detection of volatile organic compounds (VOCs). Although some plants engaged in such interactions emit singular compounds, others emit mixtures of VOCs commonly emitted by plants. We investigated the chemical ecological bases of host plant recognition in the nursery pollination mutualism between the dioecious Ficus carica and its specific pollinator Blastophaga psenes. Using Y-tube olfactometer tests, we show that B. psenes females are attracted by VOCs of receptive figs of both sexes and do not exhibit preference for VOCs of either male or female figs. Electrophysiological tests and chemical analysis revealed that of all the VOCs emitted by receptive figs, only five were found to be active on female antennae. Behavioural tests show that, in contrast to VOCs presented alone, only a blend with a particular proportion of four of these VOCs is as attractive as the odour of receptive figs, and that if there is a very small change in this blend proportion, the pollinator is no longer attracted. This study revealed that in highly specialized mutualistic interactions specificity could be mediated by a particular blend of common compounds emitted by plants

A further step towards tuning the properties of metal-chalcogenide nanocapsules by replacing skeletal oxide by sulphide ligands

Schäffer C, Todea AM, Bögge H, et al. A further step towards tuning the properties of metal-chalcogenide nanocapsules by replacing skeletal oxide by sulphide ligands. Dalton Transactions. 2013;42(2):330-333.Addition of [(Mo2O2)-O-V(mu-O)(mu-S)(aq)](2+) linker-type units to a solution/ dynamic library containing tungstates results via the formation of the complementary pentagonal {(W)W-5} units logically in the self-assembly of a mixed oxide/sulphide {(W72Mo60V)-Mo-VI}-type Keplerate, thereby demonstrating the ability to tune the capsule's skeletal softness (the (mu-O)(2) and (mu-S)(2) scenarios are known) and providing options to influence differently important capsule-substrate interactions