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Materials Data on V3Pd by Materials Project

V3Pd crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. V is bonded in a 6-coordinate geometry to two equivalent V and four equivalent Pd atoms. Both V–V bond lengths are 2.41 Å. All V–Pd bond lengths are 2.69 Å. Pd is bonded to twelve equivalent V atoms to form a mixture of edge and face-sharing PdV12 cuboctahedra.

36 MATERIALS SCIENCE↗

Materials Data on Ti3Pd by Materials Project

Ti3Pd crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. Ti is bonded in a 6-coordinate geometry to two equivalent Ti and four equivalent Pd atoms. Both Ti–Ti bond lengths are 2.53 Å. All Ti–Pd bond lengths are 2.83 Å. Pd is bonded to twelve equivalent Ti atoms to form a mixture of edge and face-sharing PdTi12 cuboctahedra.

36 MATERIALS SCIENCE↗

Materials Data on TlPd2Se3 by Materials Project

Pd2TlSe3 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded to six equivalent Se+1.67- atoms to form edge-sharing PdSe6 octahedra. All Pd–Se bond lengths are 2.55 Å. In the second Pd2+ site, Pd2+ is bonded to two equivalent Tl1+ and four equivalent Se+1.67- atoms to form edge-sharing PdTl2Se4 octahedra. Both Pd–Tl bond lengths are 3.06 Å. All Pd–Se bond lengths are 2.50 Å. Tl1+ is bonded in a 6-coordinate geometry to three equivalent Pd2+ and three equivalent Se+1.67- atoms. All Tl–Se bond lengths are 3.38 Å. Se+1.67- is bonded in a 4-coordinate geometry to three Pd2+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗

Effect of Palladium‐Tetrakis(Triphenylphosphine) Catalyst Traces on Charge Recombination and Extraction in Non‐Fullerene‐based Organic Solar Cells

Abstract The effect of the cross‐coupling catalyst tetrakis(triphenylphosphine)palladium(0) (Pd(PPh 3 ) 4 ) on the performance of a model organic bulk‐heterojunction solar cell composed of a blend of poly([2,6′‐4,8‐di(5‐ethylhexylthienyl)benzo[1,2‐b;3,3‐b]dithiophene]{3‐fluoro‐2[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl}) (PTB7‐Th) donor and 3,9‐bis(2‐methylene‐((3‐(1,1‐dicyanomethylene)‐6,7‐difluoro)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene (IOTIC‐4F) non‐fullerene acceptor is investigated. The effect of intentional addition of different amounts of Pd(PPh 3 ) 4 on morphology, free charge carrier generation, non‐geminate bulk trap‐ and surface trap‐assisted recombination as well as bimolecular recombination and charge extraction is quantified. This work shows that free charge carrier generation is affected significantly, while the impact of Pd(PPh 3 ) 4 on non‐geminate recombination processes is limited because the catalyst does not facilitate efficient trap‐assisted recombination. The studied system shows substantial robustness towards the addition of Pd(PPh 3 ) 4 in small amounts.

Schopp, Nora↗

Materials Data on Ba(P2Pd)2 by Materials Project

Ba(PdP2)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight equivalent P+1.50- atoms. All Ba–P bond lengths are 3.38 Å. Pd2+ is bonded to four equivalent P+1.50- atoms to form edge-sharing PdP4 tetrahedra. All Pd–P bond lengths are 2.41 Å. P+1.50- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Pd2+, and two equivalent P+1.50- atoms. Both P–P bond lengths are 2.20 Å.

36 MATERIALS SCIENCE↗

Materials Data on Tc3Pd by Materials Project

Tc3Pd crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are seven inequivalent Tc+0.67- sites. In the first Tc+0.67- site, Tc+0.67- is bonded to nine Tc+0.67- and three equivalent Pd2+ atoms to form a mixture of edge, face, and corner-sharing TcTc9Pd3 cuboctahedra. There are three shorter (2.72 Å) and six longer (2.74 Å) Tc–Tc bond lengths. All Tc–Pd bond lengths are 2.81 Å. In the second Tc+0.67- site, Tc+0.67- is bonded to twelve Tc+0.67- atoms to form TcTc12 cuboctahedra that share corners with six equivalent TcTc12 cuboctahedra, edges with eighteen TcTc9Pd3 cuboctahedra, and faces with eighteen TcTc9Pd3 cuboctahedra. All Tc–Tc bond lengths are 2.74 Å. In the third Tc+0.67- site, Tc+0.67- is bonded to nine Tc+0.67- and three equivalent Pd2+ atoms to form a mixture of edge, face, and corner-sharing TcTc9Pd3 cuboctahedra. There are three shorter (2.72 Å) and six longer (2.74 Å) Tc–Tc bond lengths. All Tc–Pd bond lengths are 2.81 Å. In the fourth Tc+0.67- site, Tc+0.67- is bonded to sixteen Tc+0.67- atoms to form a mixture of edge, face, and corner-sharing TcTc16 cuboctahedra. There are a spread of Tc–Tc bond distances ranging from 2.72–5.48 Å. In the fifth Tc+0.67- site, Tc+0.67- is bonded to nine Tc+0.67- and three equivalent Pd2+ atoms to form TcTc9Pd3 cuboctahedra that share corners with seventeen TcTc9Pd3 cuboctahedra, edges with sixteen TcTc9Pd3 cuboctahedra, and faces with fifteen TcTc16 cuboctahedra. All Tc–Tc bond lengths are 2.74 Å. All Tc–Pd bond lengths are 2.81 Å. In the sixth Tc+0.67- site, Tc+0.67- is bonded to twelve Tc+0.67- atoms to form TcTc12 cuboctahedra that share corners with eleven TcTc13Pd3 cuboctahedra, edges with sixteen TcTc9Pd3 cuboctahedra, and faces with twenty-one TcTc13Pd3 cuboctahedra. There are six shorter (2.72 Å) and six longer (2.74 Å) Tc–Tc bond lengths. In the seventh Tc+0.67- site, Tc+0.67- is bonded to thirteen Tc+0.67- and three equivalent Pd2+ atoms to form TcTc13Pd3 cuboctahedra that share corners with seventeen TcTc9Pd3 cuboctahedra, edges with twenty TcTc9Pd3 cuboctahedra, and faces with twenty-five TcTc13Pd3 cuboctahedra. There are a spread of Tc–Tc bond distances ranging from 2.74–5.48 Å. All Tc–Pd bond lengths are 2.81 Å. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a 6-coordinate geometry to six equivalent Tc+0.67- atoms. In the second Pd2+ site, Pd2+ is bonded in a 6-coordinate geometry to six Tc+0.67- atoms.

36 MATERIALS SCIENCE↗

Titanium Nitride as an Intermetallic Diffusion Barrier for Hydrogen Permeation in Palladium–Vanadium Composite Membranes

Hydrogen purification is a critical industrial process, and there are ongoing efforts to develop low-cost alternatives to palladium foil membranes. Titanium nitride (TiN) is studied as an interdiffusion barrier to enable hydrogen permeation in composite palladium–vanadium membranes. TiN was deposited via reactive sputtering, and films with the desired (200) orientation were obtained in the metallic regime at 400 °C under a 200 V bias to the substrate. The permeability of thin-film TiN was determined with palladium-based sandwich structures. TiN layers up to 10 nm resulted in a minimal decrease in flux (~20%) relative to a freestanding PdCu foil, which was attributed to the interfacial resistance. At greater thicknesses, the TiN layer was rate-limiting, and it was found that the effective permeability of the sputtered TiN thin films was ~6 × 10−12 mol s−1 m−1 Pa−0.5. Composite Pd|TiN|V|TiN|Pd membranes exhibited permeability values up to three times greater than pure palladium, exhibiting stability at 450 °C for over 100 h, with the lack of intermetallic diffusion and alloy formation being confirmed with XRD. The membranes were unstable at 500 °C, which was attributed to the instability of the thin Pd layer and loss of catalytic activity.

Biochemistry & Molecular Biology↗

Globally Gridded Groundwater Extraction Volumes and Costs under Six Depletion and Ponded Depth Targets

This repository contains simulated outputs from superwell – a hydro-economic tool for long-term assessment of groundwater cost and supply – providing globally gridded groundwater extractable volumes and associated unit costs ($/km³) for accessible groundwater production, based on a variety of user-defined depletion and ponded depth scenarios. Key model documentation: Niazi, H., Ferencz, S. B., Graham, N. T., Yoon, J., Wild, T. B., Hejazi, M., Watson, D. J., & Vernon, C. R. (2025). Long-term hydro-economic analysis tool for evaluating global groundwater cost and supply: Superwell v1.1. Geoscientific Model Development, 18(5), 1737-1767. https://doi.org/10.5194/gmd-18-1737-2025 Find the source code of the superwell model on GitHub: https://github.com/JGCRI/superwell Repository Overview Main output: superwell_outputs.7z contains 6 files (4.5 GB) named as superwell_py_deep_all_0.*PD_0.*DL.csv. These files present superwell outputs of global groundwater extraction volumes and cost estimates on a 0.5° scale for six scenarios with different Ponded Depth (PD; 0.3 and 0.6 m) and Depletion Limit (DL; 5%, 25%, and 40% of available volume) targets over the entire pumping lifetime of a grid cell superwell_py_deep_all_0.3PD_0.25DL_sample_100.csv contains superwell outputs for 100 data points sampled to match the global inputs' distribution superwell_py_deep_all_0.3PD_0.25DL_Grid_72548.csv contains superwell output for a single grid cell concept_v5.png provides an overview of the superwell workflow Outputs Description year_number: year of pumping depletion_limit: set depletion limit (DL) as a volume fraction of total available groundwater Mappings: continent, country, gcam_basin_id, Basin_long_name, grid_id: geographic identifiers and basin information Inputs: grid_area (km²): area of the grid cell whyclass: hydrogeological classification of the aquifer permeability (m/day), porosity (%), total_thickness (m), depth_to_water (m): aquifer properties. The geo-processed input data has been published separately: https://doi.org/10.57931/2307831 Model outputs: orig_aqfr_sat_thickness (m), aqfr_sat_thickness (m): original and remaining/instantaneous saturated thickness of the aquifer hydraulic_conductivity (m/day), transmissivity (m²/day): hydraulic properties of the aquifer radius_of_influence (m), areal_extent (km²): well radius and area of influence from the center of the well number_of_wells (-): number of wells in a grid cell determined by a ratio of well area and grid area max_drawdown (m), drawdown (m), drawdown_interference (m): well and aquifer drawdown during extraction total_head (m): total lift for the groundwater (depth to water plus drawdown) total_well_length (m): total depth of wells drilled well_yield (m³/day): pumping rate or well yield power (kW), energy (kWh): power and energy required for pumping groundwater Volume Outputs: volume_produced_perwell (m³), cumulative_vol_produced_perwell (m³): production volume metrics per well volume_produced_allwells (m³), cumulative_vol_produced_allwells (m³): aggregate extraction volumes for all wells in a grid cell available_volume (m³): available groundwater in storage for the grid cell as determined by aquifer properties depleted_vol_fraction: fraction of total volume pumped over available volumes in a grid cell (same as depletion limit) Cost Outputs: well_installation_cost ($): well installation cost based on the hydrogeological complexity of the aquifer annual_capital_cost, maintenance_cost, nonenergy_cost ($): nonenergy costs energy_cost_rate ($/kWh): electricity rate energy_cost ($): energy cost of pumping groundwater total_cost_perwell ($), total_cost_allwells ($): total annual energy and non-energy cost for each and all wells in a grid cell a unit_cost ($/m³), unit_cost_per_km3 ($/km³), unit_cost_per_acreft ($/acre-ft): total cost of pumping a unit of groundwater, indicated for different spatial units Key Resources Model documentation: Niazi, H., Ferencz, S., Graham, N., Yoon, J., Wild, T., Hejazi, M., Watson, D., & Vernon, C. (2024; In-prep). Long-term Hydro-economic Assessment Tool for Evaluating Global Groundwater Cost and Supply: Superwell v1. Geoscientific Model Development. Input data: Niazi, H., Watson, D., Hejazi, M., Yonkofski, C., Ferencz, S., Vernon, C., Graham, N., Wild, T., & Yoon, J. (2024). Global Geo-processed Data of Aquifer Properties by 0.5° Grid, Country and Water Basins. MSD-LIVE Data repository. https://doi.org/10.57931/2307831 superwell source code: https://github.com/JGCRI/superwell Cite as Niazi, H., Ferencz, S., Yoon, J., Graham, N., Wild, T., Hejazi, M., Watson, D., & Vernon, C. (2024). Globally Gridded Groundwater Extraction Volumes and Costs under Six Depletion and Ponded Depth Targets. MSD-LIVE Data repository. https://doi.org/10.57931/2307832 Contact Reach out to Hassan Niazi or Stephen Ferencz or open an issue in the superwell repository for questions or suggestions.

Earth Systems↗

Capillary Pressure Balance with Repeated Head-Up Tilt in Humans

We measured blood density (BD). plasma density (PD) and hematocrit (Ht) during repeated 70 deg head-up tilt (HUT) consisting of a pre-drink period with two supine (P and P3) and two HUT (P2 and P4) phases of 45 min each. At the end of P4 test subjects (N=8) drank 10 ml/kg body weight of isotonic (290 mOsm/kg) sodium chloride (ISO) or hypotonic (<10 mOsm/kg) unsweetened us (HYP), or nothing (control: CON). The following periods continued the supine (P5, P7) / upright (P6) sequence. Mass density of plasma and whole blood using a "mechanical oscillation" technique were measured from ear lobe blood. Tilting altered (p<0.001) BD, PD, and Ht in all consecutive Phases. BD and PD were different (p<0.05) between CON. HYP. and ISO Phases 6 and 7. The computed mass density of fluid (FD). which moved between intra. and extravascular compartments. averaged 1008 g/l and was the same in any conditions. In the non-drink treatment (P3, P5, P7), supine PV steadly decreased when compared to P1. Tilt-induced PV shifts ranged from 9.7 to 16.7% when compared to PV du. ring the respective previous Phases. After drinking, PV increased above CON values at the end of Phase 7 by 12.9% with ISO, and by 6.6% with HYP. Progressive hemoconcentration. occurred during non-drink supine; isotonic saline ingestion increased supine PV a control level but did not stop or reverse the decrease of upright hemoconcentration. Upright density values were not slowed with repeated upright tilting; decreased fluid loss occurred in consecutive upright periods. Upright capillary pressure balance was achieved with diminished plasma volume loss during repeated tilting.

Hinghofer-Szalkay, H. G.↗

Materials Data on SmSiPd by Materials Project

SmPdSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are three inequivalent Sm2+ sites. In the first Sm2+ site, Sm2+ is bonded in a 1-coordinate geometry to six Pd2+ and six Si4- atoms. There are a spread of Sm–Pd bond distances ranging from 2.99–3.15 Å. There are a spread of Sm–Si bond distances ranging from 3.12–3.29 Å. In the second Sm2+ site, Sm2+ is bonded in a 6-coordinate geometry to six Si4- atoms. There are a spread of Sm–Si bond distances ranging from 3.00–3.15 Å. In the third Sm2+ site, Sm2+ is bonded in a 1-coordinate geometry to six Pd2+ and six Si4- atoms. There are a spread of Sm–Pd bond distances ranging from 2.96–3.17 Å. There are a spread of Sm–Si bond distances ranging from 3.09–3.28 Å. There are three inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded in a 4-coordinate geometry to five Sm2+ and three Si4- atoms. There are one shorter (2.53 Å) and two longer (2.54 Å) Pd–Si bond lengths. In the second Pd2+ site, Pd2+ is bonded in a 3-coordinate geometry to three equivalent Sm2+ and three equivalent Si4- atoms. There are two shorter (2.54 Å) and one longer (2.61 Å) Pd–Si bond lengths. In the third Pd2+ site, Pd2+ is bonded in a 6-coordinate geometry to four Sm2+ and four Si4- atoms. There are a spread of Pd–Si bond distances ranging from 2.56–2.90 Å. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 10-coordinate geometry to six Sm2+ and four Pd2+ atoms. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to six Sm2+, three equivalent Pd2+, and one Si4- atom. The Si–Si bond length is 2.64 Å. In the third Si4- site, Si4- is bonded in a 10-coordinate geometry to six Sm2+, three Pd2+, and one Si4- atom.

36 MATERIALS SCIENCE↗

Exceptional magnetic and magnetoelastic behavior of rare-earth non-centrosymmetric Sm 7 Pd 3

Magnetic compounds possessing an intrinsic combination of near-zero magnetization with high magnetic anisotropy are highly desirable for spinronic applications and memory recording. A comprehensive study of Sm 7 Pd 3 binary compound uncovered a unique combination of strong magnetoelastic behavior, very low net magnetization, and exceptionally high magnetic coercivity. The temperature-dependent X-ray synchrotron powder diffraction study indicates the abrupt changes in the compound's lattice parameters at the magnetic ordering temperature of T C =169 K, although the crystal structure remains non-centrosymmetric hexagonal Th 7 Fe 3 -type down to 6 K. Density functional theory calculations confirm high intrinsic magnetocrystalline anisotropy of Sm 7 Pd 3 , which explains the extremely large coercivity of the polycrystalline sample, up to H cr = 130 kOe at 2 K. In conclusion, this discovery brings to life a novel class of highly anisotropic materials that are distinctly different from known spintronic materials, making them interesting future systems for magnetic memory research.

36 MATERIALS SCIENCE↗

Materials Data on Na4H4PdPt by Materials Project

Na4PtPdH4 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to five H1- atoms to form a mixture of edge and corner-sharing NaH5 square pyramids. There are one shorter (2.40 Å) and four longer (2.58 Å) Na–H bond lengths. In the second Na1+ site, Na1+ is bonded to five H1- atoms to form a mixture of distorted edge and corner-sharing NaH5 square pyramids. There are one shorter (2.42 Å) and four longer (2.58 Å) Na–H bond lengths. Pt2- is bonded in a linear geometry to two equivalent H1- atoms. Both Pt–H bond lengths are 1.67 Å. Pd2+ is bonded in a linear geometry to two equivalent H1- atoms. Both Pd–H bond lengths are 1.70 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to five Na1+ and one Pt2- atom to form a mixture of edge and corner-sharing HNa5Pt octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the second H1- site, H1- is bonded to five Na1+ and one Pd2+ atom to form HNa5Pd octahedra that share corners with five equivalent HNa5Pd octahedra and edges with eight HNa5Pt octahedra. The corner-sharing octahedra tilt angles range from 0–6°.

36 MATERIALS SCIENCE↗

Structure and activity of supported bimetallic NiPd nanoparticles: influence of preparation method on CO 2 reduction

Here, bimetallic Ni-Pd and monometallic reference catalysts were prepared by decomposing organometallic precursors, Ni(cod) 2 and Pd 2 (dba) 3 , leading to nanoparticles with sizes ranging from 3 to 6 nm. Two different synthesis procedures were followed: i) solution synthesis using capping ligand (hexadecylamine) followed by impregnation of pre-formed nanoparticles on SiO 2 , called Sol-immobilization (SI); and 2) direct precursor decomposition onto SiO 2 , without stabilizer, called Direct Decomposition (DD). Samples prepared by SI procedure are alloyed bimetallic nanoparticles, whereas samples obtained by DD one show phase segregation. Interestingly, DD samples show better activity for CO 2 hydrogenation into CO (reverse water-gas shift reaction - RWGS) than SI ones. The best compromise between activity for CO 2 activation (at lower temperature) and CO selectivity was achieved with Ni DD and NiPd DD catalysts. Moreover, the addition of palladium increased the concentration of surface undercoordinated sites, which chemisorb CO weakly, thus improving activity and selectivity, in opposition to other samples that chemisorb CO strongly, in multiband configuration. In the presence of Pd, different decomposition rates drive the formation of smaller and more active Ni clusters. The knowledge acquired here on the influence of synthesis conditions on the catalytic properties of Ni-Pd catalysts should guide us to better catalysts for CO 2 transformations into valuable products.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

2,4,6–Triphenylpyridinium: A Bulky, Highly Electron–Withdrawing Substituent Which Enhances Properties of Nickel(II) Ethylene Polymerization Catalysts

The reactivity of Ni(II) and Pd(II) olefin polymerization catalysts can be enhanced by introduction of electron-withdrawing substituents on the supporting ligands rendering the metal centers more electrophilic. Reported here is a comparison of ethylene polymerization activity of a classical salicyliminato nickel catalyst substituted with the powerful electron-withdrawing 2,4,6-triphenylpyridinium (trippy) group to its’ –CF3 analog. The trippy substituent is substantially more electron-withdrawing (σmeta = 0.63) than the trifluoromethyl group (σmeta = 0.43) which results in a ca. 8-fold increase in catalytic turnover frequency. An additional advantage of trippy is its’ high steric bulk relative to the trifluoromethyl group. This feature results in a four-fold increase in polymer molecular weight due to enhanced retardation of chain transfer. Here, a significant increase in catalyst lifetime is observed as well.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Polyhydrido Copper Nanoclusters with a Hollow Icosahedral Core: [Cu 30 H 18 {E 2 P(OR) 2 } 12 ] (E=S or Se; R= n Pr, i Pr or i Bu)

Although atomically precise polyhydrido copper nanoclusters are of prime interest for a variety of applications, they have so far remained scarce. Here, we describe the synthesis of a dithiophosphate-protected copper(I) hydride-rich nanocluster (NC), [Cu 30 H 18 {S 2 P(O n Pr) 2 } 12 ] ( 1 H ), fully characterized by various spectroscopic methods and single-crystal X-ray diffraction. The X-ray structure of 1 H reveals an unprecedented central Cu 12 hollow icosahedron. Six faces of this icosahedron are capped by Cu 3 triangles, the whole Cu 30 core being wrapped by twelve dithiophosphate ligands and the whole cluster has ideal S 6 symmetry. The locations of the 18 hydrides in 1 H were ascertained by a single-crystal neutron diffraction study. They are composed of three types: capping μ 3 -H, interstitial μ 4 -H (seesaw) and μ 5 -H ligands (square pyramidal), in good agreement with the DFT simulations. The numbers of hydrides and ligand resonances in the 1 H NMR spectrum of 1 H are in line with their coordination environment in the solid state, retaining the S 6 symmetry in solution. Furthermore, two new Se-protected polyhydrido copper nanoclusters, [Cu 30 H 18 {Se 2 P(OR) 2 } 12 ] ( 2 H : R= i Pr 3 H : R= i Bu) were synthesized from their sulfur relative 1 H via ligand displacement reaction and their X-ray structures feature the exceptional case where both the NC shape and size are fully conserved during the course of ligand exchange. DFT and TD-DFT calculations allow understanding the bonding and optical properties of clusters 1 H – 3 H . In addition, the reaction of 1 H with [Pd(PPh 3 ) 2 Cl 2 ] in the presence of terminal alkynes led to the formation of new bimetallic Cu–Pd alloy clusters [PdCu 14 H 2 {S 2 P(O n Pr) 2 } 6 (C≡CR) 6 ] ( 4 : R=Ph; 5 : R = C 6 H 4 F).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

2,4,6‐Triphenylpyridinium: A Bulky, Highly Electron‐Withdrawing Substituent That Enhances Properties of Nickel(II) Ethylene Polymerization Catalysts

Abstract The reactivity of Ni II and Pd II olefin polymerization catalysts can be enhanced by introduction of electron‐withdrawing substituents on the supporting ligands rendering the metal centers more electrophilic. Reported here is a comparison of ethylene polymerization activity of a classical salicyliminato nickel catalyst substituted with the powerful electron‐withdrawing 2,4,6‐triphenylpyridinium (trippy) group to the ‐CF 3 analogue. The trippy substituent is substantially more electron‐withdrawing (σ meta =0.63) than the trifluoromethyl group (σ meta =0.43) which results in a ca. 8‐fold increase in catalytic turnover frequency. An additional advantage of trippy is the high steric bulk relative to the trifluoromethyl group. This feature results in a four‐fold increase in polymer molecular weight owing to enhanced retardation of chain transfer. A significant increase in catalyst lifetime is observed as well.

Janeta, Mateusz↗

Ag Isotopic Evolution of the Mantle During Accretion: New Constraints from Pd and Ag Metal-Silicate Partitioning

Decay of (sup 107) Pd to (sup 107) Ag has a half-life of 6.5 times 10 (sup 6) mega-annums. Because these elements are siderophile but also volatile, they offer potential constraints on the timing of core formation as well as volatile addition. Initial modelling has shown that the Ag isotopic composition of the bulk silicate Earth (BSE) can be explained if accretion occurs with late volatile addition. These arguments were tested for sensitivity for pre-cursor Pd/Ag contents, and for a fixed Pd/Ag ratio of the BSE of 0.1. New Ag and Pd partitioning data has allowed a better understanding of the partitioning behavior of Pd and Ag during core formation. The effects of S, C and Si, and the effect of high temperature and pressure has been evaluated. We can now calculate D(Ag) and D(Pd) over the wide range of PT conditions and variable metallic liquid compositions that are known during accretion. We then use this new partitioning information to revisit the Ag isotopic composition of the BSE during accretion.

Righter, K.↗

From Trivial Kondo Insulator Ce 3 Pt 3 Bi 4 to Topological Nodal-Line Semimetal Ce 3 Pd 3 Bi 4

In this work, using the density functional theory combined with dynamical mean-field theory, we have performed systematic study of the electronic structure and its band topology properties of Ce 3 Pt 3 Bi 4 and Ce 3 Pd 3 Bi 4 . At high temperatures ( ~ 290 K ), the electronic structures of both compounds resemble the open-core 4 f density functional calculation results. For Ce 3 Pt 3 Bi 4 , clear hybridization gap can be observed below 72 K, and its coherent momentum-resolved spectral function below 18 K exhibits an topologically trivial indirect gap of ~ 6 meV and resembles density functional band structure with itinerant 4 f state. For Ce 3 Pd 3 Bi 4 , no clear hybridization gap can be observed down to 4 K, and its momentum-resolved spectral function resembles electron-doped open-core 4 f density functional calculations. The band nodal points of Ce 3 Pd 3 Bi 4 at 4 K are protected by the gliding-mirror symmetry and form ringlike structure. Therefore, the Ce 3 Pt 3 Bi 4 compound is topologically trivial Kondo insulator while the Ce 3 Pd 3 Bi 4 compound is topological nodal-line semimetal.

36 MATERIALS SCIENCE↗