A combined experimental and theoretical study of the molecular inclusion of organometallic sandwich complexes in a cavitand receptor

We describe herein a detailed study of the inclusion processes of several positively charged organometallic sandwich complexes inside the aromatic cavity of the self-folding octaamide cavitand 1. In all cases, the binding process produces aggregates with a simple 1:1 stoichiometry. The resulting inclusion complexes are not only thermodynamically stable, but also kinetically stable on the (1)H NMR spectroscopy timescale. The binding constants for the inclusion complexes were determined by different titration techniques. We have also investigated the kinetics of the binding process and the motion of the metallocenes included in the aromatic cavity of the host. Using DFT-based calculations, we have evaluated the energies of a diverse range of potential binding geometries for the complexes. We then computed the proton chemical shifts of the included guest in each one of the binding geometries. The agreement between the averaged computed values and the experimentally determined chemical shifts clearly supports the proposed binding geometries that we assigned to the inclusion complexes formed in solution. The combination of experimental and theoretical results has allowed us to elucidate the origins of the distinct features detected in the complexation process of the different guests, as well as their different motions inside the host.     

Recent developments in the application of nanoparticles prepared from w/o microemulsions in heterogeneous catalysis

This paper reviews the use of microemulsions, especially the water-in-oil (w/o) microemulsions, for preparation of nanoparticles that are employed as catalyst components in heterogeneous catalytic reactions. The objective is to show the growing interest of using microemulsions in the preparation of different types of materials such as metals, single metal oxides or mixed metal oxides with a broad range of application in heterogeneous catalysis and also in electrocatalysis. In most cases, the catalytic material showed improved catalytic properties as a result of the special synthesis environment created by the microemulsions. Still, research is needed for a better understanding of such beneficial effects. In addition, this method needs improvements in order to produce, in an environmentally friendly way, a suitable amount of material for use in industrial-scale catalytic processes.     

Unintended consequences of collocation: using agent-based modeling to untangle effects of communication delay and in-group favor

In studies about office arrangements that have individuals working from remote locations, researchers usually hypothesize advantages for collocators and disadvantages for remote workers. However, empirical findings have not shown consistent support for the hypothesis. We suspect that there are unintended consequences of collocation, which can offset well-recognized advantages of being collocated. To explain these unintended consequences, we developed a multi-agent model to complement our laboratory-based experiment. In the lab, collocated subjects did not perform better than the remote even though collocators had faster communication channels and in-group favor towards each other. Results from the multi-agent simulation suggested that in-group favoritism among collocators caused them to ignore some important resource exchange opportunities with remote individuals. Meanwhile, communication delay of remote subjects protected them from some falsely biased perception of resource availability. The two unintended consequences could offset the advantage of being collocated and diminish performance differences between collocators and remote workers. Results of this study help researchers and practitioners recognize the hidden costs of being collocated. They also demonstrate the value of coupling lab experiments with multi-agent simulation.

Design and synthesis of bioactive 1,2-annulated adamantane derivatives

Adamantanopyrrolidines 8, 9 and 10, adamantanopyrrolidines 16 and 18, adamantanoxazolone 20, adamantanopyrazolone 23, adamantanopyrazolothione 24 and adamantanocyclopentanamine 32 were synthesized and tested for anti-influenza A virus and trypanocidal activity. The stereoelectronic requirements for optimal antiviral and trypanocidal potency were investigated. Pyrrolidine 16 proved to be the most active of the compounds tested against influenza A virus, being 4-fold more active than amantadine, equipotent to rimantadine and 19-fold more potent than ribavirin. Oxazolone 20 showed significant trypanocidal activity against bloodstream forms of the African trypanosome, Trypanosoma brucei, being approximately 3 times more potent than rimantadine and almost 50-fold more active than amantadine.     

A new colorimetric test for solid-phase amines and thiols

A new, efficient, sensitive, and reliable color test for the visual detection of resin-bound primary and secondary amines is described. The reaction between amines and 1-methyl-2-(4'-nitrophenyl)-imidazo[1,2- a]pyrimidinium perchlorate (DESC) provides the "on-bead generated" colored stable intermediate azadiene. The developed protocols allow detection of resin-bound primary amines in the presence of secondary amines. The test can also be used for the detection of resin bound thiols.     

Stereoselective synthesis of woody fragrances related to georgyone and arborone

The synthesis of two very powerful and pleasant new odorants has been carried out from a common intermediate.     

K3[MO4][MO3N] (M=Tc,Re) – Nitridotrioxidorhenate and -technetate from Highly Alkaline Media

The reactions of ammonium perrhenate and pertechnetate in highly alkaline medium led to the isotypic mixed anionic nitridotrioxidorhenate and -technetate K ₃[MO₄][MO₃N] (M= Tc, Re). Both compounds occur as colorless crystals, which were investigated by single crystal X-ray diffraction. Furthermore, K₃[ReO₄][ReO₃N] has been studied by means of X-ray photoelectron spectroscopy to determine the oxidation state of rhenium. The obtained results have been complemented by magnetic measurements. IR and Raman spectroscopy indicated the presence of Re−O as well as Re−N bonds.