P addition and transfer involving a tetraphosphenium ion.

Triphospha[3]ferrocenophane Fe(CH-PTip)PCl (Tip = 2,4,6-tri(isopropyl)phenyl) has been prepared and its suitability to generate the corresponding bisphosphanylphosphenium ion has been explored. By formal addition of P to the latter, an unprecedented tetraphosphenium ion forms which likewise is capable of P transfer and qualifies as Lewis superacid based on its computed fluoride ion affinity. As a solid, this species is stable and conveniently storable, featuring a remarkably long P-P bond (2.

Controlled Ring Opening of a Tetracyclic Tetraphosphane with Twofold Metallocene Bridging.

A direct route to a doubly ferrocene bridged tetracyclic tetraphosphane 1 was developed via reductive coupling of Fe(CpPCl) (2 a), where a chlorine terminated linear P-compound 3 could be identified as an intermediate. Selective P-P bond activation was further achieved by reacting 1 with elemental selenium or [Cp*Al], where regioselective insertion of Se or Al atoms resulted in ferrocenylene bridged [PSe] (4) or [PAl] (7) moieties. Compound 7 can be transformed to a hydrogen terminated linear P species, 8, with protic solvents.

Gradual Coordination and Reversible P-P Bond Activation of a P -Unit with Transition Metal Carbonyls.

Coordination of a stereochemically defined P -chain to a series of transition metal carbonyls [M(CO) ] (M = Mn (x = 5, z = 1), Fe (x = 4, z = 2) or Co (x = 4, z = 1)) is explored using a [3]ferrocenophane scaffold. A gradual transition from η -, η - to η -coordination is observed where in the η -mode the terminal positions of the phosphorus chain are bridged. With an excess of cobalt carbonyl successive P-P bond activation and gradual separation of the central phosphorus atoms from the phosphorus chain has been observed.

At the limits of bisphosphonio-substituted stannylenes.

Donor stabilization of Sn(II) and Pb(II) halides with 1,1'-ferrocenylene bridged bisphosphanes has been explored for Fe(CHP(CH)) (dppf), and Fe(CHPH(CH)). These bisphosphanes are reacted with SnBr and PbCl with and without additional Lewis acid (AlCl) forming acyclic and cyclic donor adducts from which the latter represent bisphosphoniotetrylenes. Since dynamic exchange in solution is observed, characterization includes solution and solid-state NMR in addition to SC-XRD, amended by DFT calculations.

A General Strategy for Increasing the Air Stability of Phosphines Including Primary Phosphines.

A general approach for increasing the air-stability of various primary phosphines in the absence of kinetic stabilization is presented that contrasts with previous interpretations, which were limited to specific phosphines. This contribution shows the synthesis of a series of air-stable primary phosphines Fc(CH ) PH , where n=0,1,2,3; and Fc=ferrocenyl, and their corresponding isolable primary phosphine oxides. It was demonstrated that the ferrocene moiety exerts an antioxidant effect on the primary phosphine group, which is intermolecular, solvent dependent and increases with the electron density on the ferrocene moiety.

Screening for Resistant Bacteria, Antimicrobial Resistance Genes, Sexually Transmitted Infections and spp. in Tissue Samples from Predominantly Vaginally Delivered Placentae in Ivory Coast and Ghana.

Medical complications during pregnancy have been frequently reported from Western Africa with a particular importance of infectious complications. Placental tissue can either become the target of infectious agents itself, such as, e.g.

Gradual Donor Stabilization of a Transient Ferrocene Bridged Bisphosphanyl Phosphenium Cation.

A transient phosphenium cation embedded into a [3]ferrocenophane scaffold was formed via chloride abstraction. The cation has been trapped with phosphane, carbene, and silylene donors resulting in stable adducts or bond activation of the ferrocenophane bridge. In the absence of donors, dimerization of the phosphenium cation to the corresponding dication is observed or P-C bond activation with migration of a substituent leading to a putative phosphoniodiphosphene.

Simulation of transient heat transfer during forced convection cooling of cocoyam (L.) Schott tubers.

In this study, a prediction model based on transient heat transfer was modified and validated using experimental data. The time required to cool tubers from field temperature of 30 ± 2 °C to the target storage temperature of 12 ± 0.2 °C was predicted directly from the model.

Optimization of roughing filtration unit for a handwashing wastewater recirculation point-of-use system.

A downward roughing filter unit consisting of silica sand as the filter medium was optimized for performance towards removal of turbidity and suspended solids from handwashing wastewater. Design-Expert software was employed to optimize media particle size, filter depth, and flowrate. Linear and quadratic models were found to best fit the responses of turbidity and suspended solids removal, respectively.

-Symmetric P-Stereogenic Ferrocene Ligands with Heavier Chalcogenophosphinous Acid Ester Donor Sites.

-Butyl-substituted diphospha[2]ferrocenophane was used as a stereochemically confined diphosphane to investigate the addition of various dichalcoganes (R2Ch2; Ch = S, Se, Te and R = Me, Ph). Bischalcogenophosphinous acid esters bearing four soft donor sides were obtained as a mixture of and diastereomers and characterized by means of multinuclear NMR and X-ray analysis. The coordination chemistry of multidentate ligand was explored toward d coinage metal centers (Cu(I), Ag(I), and Au(I)), yielding various bimetallic complexes.

Chalcogen-Transfer Rearrangement: Exploring Inter- versus Intramolecular P-P Bond Activation.

Invited for the cover of this issue are Rudolf Pietschnig and co-workers at the University of Kassel and Zsolt Kelemen at Budapest University of Technology and Economics. The image depicts Selene, the goddess of the moon in ancient Greek mythology, and the cycle of chalcogen-transfer rearrangement in the starry sky over the hills of the mountainous region of the northern shore of Lake Balaton (Mts. Badacsony and Gulács) in Hungary.

Chalcogen-Transfer Rearrangement: Exploring Inter- versus Intramolecular P-P Bond Activation.

tert-Butyl-substituted diphospha[2]ferrocenophane has been used as a stereochemically confined diphosphane to explore the addition of O, S, Se and Te. Although the diphosphanylchalcogane has been obtained for tellurium, all other chalcogens give diphosphane monochalcogenides. The latter transform via chalcogen-transfer rearrangement to the corresponding diphosphanylchalcoganes upon heating.

A modification of a traditional Ethiopian maize store for solar powered ambient drying to reduce post-harvest losses.

A gombisa is a traditional Ethiopian structure widely used for maize storage over several months. It lacks adequate ventilation for timely moisture removal, which promotes mold development and aflatoxin production. In this study, a traditional gombisa was compared to one modified by installing a solar powered fan to provide forced ambient air ventilation during daytime.