Dynamic, reversible oxidative addition of highly polar bonds to a transition metal

The combination of Pt0 complexes and indium trihalides leads to compounds that form equilibria in solution between their In-X oxidative addition (OA) products (PtII indyl complexes) and their metal-only Lewis pair (MOLP) isomers (LnPt→InX3). The position of the equilibria can be altered reversibly by changing the solvent, while the equilibria can be reversibly and irreversibly driven towards the MOLP products by addition of further donor ligands. The results mark the first observation of an equilibrium between MOLP and OA isomers, as well as the most polar bond ever observed to undergo reversible oxidative addition to a metal complex. In addition, we present the first structural characterization of MOLP and oxidative addition isomers of the same compound. The relative energies of the MOLP and OA isomers were calculated by DFT methods, and the possibility of solvent-mediated isomerization is discussed

Tetraiododiborane(4) (B2_2I4_4) is a Polymer based on sp3^3 Boron in the Solid State

Herein we present the first solid‐state structures of tetraiododiborane(4) (B$_2$I$_4$), which was long believed to exist in all phases as discrete molecules with planar, tricoordinate boron atoms, like the lighter tetrahalodiboranes(4) B$_2$F$_4$, B$_2$Cl$_4$, and B$_2$Br$_4$. Single‐crystal X‐ray diffraction, solid‐state NMR, and IR measurements indicate that B$_2$I$_4$ in fact exists as two different polymeric forms in the solid state, both of which feature boron atoms in tetrahedral environments. DFT calculations are used to simulate the IR spectra of the solution and solid‐state structures, and these are compared with the experimental spectra

Dibortetraiodid (B2_2I4_4) ist im Festkörper ein Polymer aus sp3‐hybridisiertem Bor

Anhand der ersten Festkörperstrukturen von Dibortetraiodid (B$_2$I$_4$) wird gezeigt, dass dieses nicht, wie lange angenommen, analog zu den leichteren Dibortetrahalogeniden B$_2$F$_4$, B$_2$Cl$_4$ und B$_2$Br$_4$ in allen Aggregatzuständen in Form diskreter Moleküle mit planaren, dreifach koordinierten Boratomen vorliegt. Röntgenstrukturanalysen, Festkörper‐NMR‐ und IR‐Messungen zeigen, dass B$_2$I$_4$ im Festkörper in zwei polymeren Konformeren vorkommt, die tetraedrisch koordinierte Boratome enthalten. Anhand von DFT‐Rechnungen werden die IR‐Spektren in Lösung und im Festkörper simuliert und mit den experimentellen Daten verglichen

GEC/ESTRO-EAU recommendations on temporary brachytherapy using stepping sources for localised prostate cancer

Background and purpose: The aim of this paper is to present the GEC/ESTRO-EAU recommendations for template and transrectal ultrasound (TRUS) guided transperineal temporary interstitial prostate brachytherapy using a high dose rate iridium-192 stepping source and a remote afterloading technique. Experts in prostate brachytherapy developed these recommendations on behalf of the GEC/ESTRO and of the EAU. The paper has been approved by both GEC/ESTRO steering committee members and EAU committee members. Patients and methods: Interstitial brachytherapy (BT) to organ confined prostate cancer can be applied as a boost treatment in combination with external beam radiation therapy (EBRT) using a proper number of BT fractions in curative intent. Temporary transperineal BT alone or in combination with EBRT are feasible as a palliative/salvage treatment modality because of local recurrence, however, without large clinical experience. The use of temporary BT as a monotherapy is subject of ongoing clinical research. Results: Recommendations for pre-treatment investigations, patient selection, equipment and facilities, the clinical team, the implant procedure (treatment planning and needle implantation) dose and fractionation, reporting, management of side effects and follow-up are given. Conclusions: These recommendations are intended to be technically and advisory in nature, but the ultimate responsibility for the medical decision rests with the treating physician. Although, this paper represents the consensus of an interdisciplinary group of experts, TRUS and template guided temporary transperineal interstitial implants in prostate cancer are a constantly evolving field and the recommendations are subject to modifications as new data become available. (c) 2004 Elsevier Ireland Ltd. All rights reserve

Boranediyl‐ and Diborane(4)‐1,2‐diyl‐Bridged Platinum A‐Frame Complexes

Diplatinum A‐frame complexes with a bridging (di)boron unit in the apex position were synthesized in a single step by the double oxidative addition of dihalo(di)borane precursors at a bis(diphosphine)‐bridged Pt$^{0}$$_{2}$ complex. While structurally analogous to well‐known μ‐borylene complexes, in which delocalized dative three‐center‐two‐electron M‐B‐M bonding prevails, theoretical investigations into the nature of Pt−B bonding in these A‐frame complexes show them to be rare dimetalla(di)boranes displaying two electron‐sharing Pt−B σ‐bonds. This is experimentally reflected in the low kinetic stability of these compounds, which are prone to loss of the (di)boron bridgehead unit

Soil thermal behavior in different moisture condition: an overview of ITER project from laboratory to field test monitoring

The thermal properties of soils can be considered one of the most important parameters for many engineering projects designing. In detail, the thermal conductivity plays a fundamental role when dimensioning ground heat exchangers, especially very shallow geothermal (VGS) systems, interesting the first 2 m of depth from the ground level. However, the determination of heat transfer in soils is difficult to estimate, because depends on several factors, including, among others, particle size, density, water content, mineralogy composition, ground temperature, organic matter. The performance of a VSG system, as horizontal collectors or special forms, is strongly correlated to the kind of sediment at disposal and suddenly decreases in case of dry-unsaturated conditions in the surrounding soil. Therefore, a better knowledge of the relationship between thermal conductivity and water content is required for understanding the VSG systems behavior in saturated and unsaturated conditions. Key challenge of ITER Project, funded by European Union, is to understand how to enhance the heat transfer of the sediments surrounding the pipes, taking into account the interactions between the soil, the horizontal heat exchangers and the surrounding environment. In order to obtain reliable data for modelling, an interdisciplinary approach is used. In laboratory the physical-thermal properties of more than 15 soil mixtures, consisting in (i) natural soil, (ii) pure sand and (iii) mixtures of pure sand and clay additives, have been tested under different water content percentages and different consolidation degree. Then the same parameters are monitored in the project case study, in Eltersdorf, (Germany), where five helix collectors are installed in horizontal trenches filled in with five different mixtures already tested in laboratory. In addition, a monitoring system allows to record every 15 minutes, by means of devoted sensors, values related to ground temperature (undisturbed, inside and outside each helix), fluid temperature and flow running in the collectors, volumetric water content at 20 and 60 cm depth. Moreover, a meteorological station provides climatic data acquisition as rainfall, wind speed, relative humidity and air temperature. The main results achieved until now are useful for future modeling because shed new light (i) on the differences between data collected in laboratory and in the field and (ii) on the influence of the technical solution adopted in situ to fill in the trenches, able to create a non-homogeneous distribution of the soil bodies around the helix.Abstract 5th International Conference Novel Methods for Subsurface Characterization and Monitoring: From Theory to Practice, NovCare 2017, Dresden, Germany, 06-09.06.201