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1. Requirements for Late-Stage Hydroboration of Pyridine N-Heterocyclic Carbene Iron(0) Complexes: The Role of Ancillary Ligands

   https://doi.org/10.1021/acs.organomet.1c00307  

   Kiernicki, John J.; Zeller, Matthias; Szymczak, Nathaniel K. (January 2021, Organometallics)

   null (Ed.)

   A series of zerovalent iron complexes were synthesized that contain allylic substituents attached to a 2,6-bis(imidazol-2-ylidene)pyridine pincer ligand. These species varied in the identity of their ancillary ligands and were used to study the requirements and limitations of late-stage hydroboration. While late-stage ligand functionalization can facilitate the incorporation of Lewis acidic boranes into a ligand scaffold, thereby alleviating Lewis acid/base incompatibilities of the free ligand, we identify and discuss complicating factors that arise from complexes containing labile M–L bonds. 

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2. Ionization of gold (γ-methoxy)vinyl complexes generates reactive gold vinyl carbene complexes

   https://doi.org/10.1039/c9sc01574d  

   Kim, Nana; Widenhoefer, Ross A. (June 2019, Chemical Science)

   Cationic gold vinyl carbene/allylic cation complexes of the form ( E )-[(L)AuC(H)C(H)CAr 2 ] + OTf − {L = IPr, Ar = Ph [( E )- 5a ], L = IPr, Ar = 4-C 6 H 4 OMe [( E )- 5b ], L = P( t -Bu) 2 o -biphenyl, Ar = 4-C 6 H 4 OMe [( E )- 5c ]} were generated in solution via Lewis acid-mediated ionization of the corresponding gold (γ-methoxy)vinyl complexes ( E )-(L)AuC(H)C(H)C(OMe)Ar 2 at or below −95 °C. Complexes ( E )- 5b and ( E )- 5c were fully characterized in solution employing multinuclear NMR spectroscopy, which established the predominant contribution of the aurated allylic cation resonance structure and the significant distribution of positive charge into the γ-anisyl rings. Complex ( E )- 5b reacted rapidly at −95 °C with neutral two-electron, hydride, and oxygen atom donors exclusively at the C1 position of the vinyl carbene moiety and with p -methoxystyrene to form the corresponding vinylcyclopropane. In the absence of nucleophile ( E )- 5a decomposed predominantly via intermolecular carbene dimerization whereas formation of 1-aryl-5-methoxy indene upon ionization of ( Z )-(IPr)AuC(H)C(H)C(OMe)(4-C 6 H 4 OMe) 2 [( Z )- 6b ] implicated an intramolecular Friedel–Crafts or electrocyclic Nazarov pathway for the decomposition of the unobserved vinyl carbene complex ( Z )-[(IPr)AuC(H)C(H)C(4-C 6 H 4 OMe) 2 ] + OTf − [( Z )- 5b ]. 

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3. Heat Treatment Effect on the Corrosion Resistance of 316L Stainless Steel Produced by Laser Powder Bed Fusion

   https://doi.org/10.3390/met15010041  

   Sangoi, Kevin; Nadimi, Mahdi; Song, Jie; Fu, Yao (January 2025, Metals)

   This study explores the effect of heat treatment on the microstructural characteristics and corrosion resistance of 316L stainless steels (SSs) produced via laser powder bed fusion (L-PBF), focusing on anisotropic corrosion behavior—a relatively less explored phenomenon in LPBF 316L SSs. By systematically analyzing the effects of varying heat treatment temperatures (500 °C, 750 °C, and 1000 °C), this work uncovers critical correlations between microstructural evolution and corrosion properties. The findings include the identification of anisotropic corrosion resistance between horizontal (XY) and vertical (XZ) planes, with the vertical plane demonstrating higher pitting and repassivation potentials but greater post-repassivation current densities. Furthermore, this study highlights reductions in grain size, dislocation density, and melt pool boundaries with increasing heat treatment temperatures, which collectively diminishes corrosion resistance. These insights advance the understanding of processing–structure–property relationships in additively manufactured metals, providing practical guidelines for optimizing thermal post-processing to enhance material performance in corrosive environments. 

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4. Investigation of the Drivers of Sea Surface Salinity and North Atlantic Climate Variability Using a Stochastic Model

   https://doi.org/10.1175/JCLI-D-24-0694.1  

   Liu, Glenn; Kwon, Young-Oh; Frankignoul, Claude (October 2025, Journal of Climate)

   Abstract The role of ocean dynamics in Atlantic climate variability and predictability is often studied through the lens of sea surface temperature (SST). Unlike SST, sea surface salinity (SSS) is not directly damped by surface fluxes, and its low-frequency variability responds primarily to oceanic processes. This study investigates the drivers of SSS variability using a stochastic model hierarchy to disentangle oceanic and atmospheric contributions to Atlantic climate variability, in particular, the role of local vertical processes. Representation of SST and SSS persistence and variance is especially improved by the introduction of damping of anomalies below the mixed layer, though SSS anomalies remain too persistent. The effect of SST–evaporation feedback on SSS is comparatively smaller except in regions with strong SST–SSS correlation. Despite the lack of representation of geostrophic advection, the stochastic model successfully reproduces spatial patterns of recurring SST/SSS anomalies in the Community Earth System Model 1 (CESM1) Large Ensemble at monthly to interannual time scales. At multidecadal time scales, the stochastic model is unable to simulate the amplitude of SST/SSS variability, but their spatial patterns are broadly reproduced, suggesting that direct atmospheric forcing and local vertical processes are important for capturing these features. Further analysis of the processes missing from the stochastic model suggests that the lack of geostrophic advection is largely responsible for too persistent SSS in the stochastic model, while the lack of interannual mixed-layer depth variability explains the underestimated persistence and variance in some regions for both SST and SSS. 

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5. Primary and Secondary Coordination Sphere Lewis Acid Interactions in β-Phosphinoethylborane-ligated Rhodium and Iridium Complexes

   https://doi.org/10.1039/d5nj01429h  

   Nichols, Brian R; Petersen, Jeffrey L; Dolinar, Brian; Popp, Brian V (July 2025, New Journal of Chemistry)

   Flexible ambiphilic ligand scaffolds have garnered attention in catalysis due to their ability to adopt multiple binding orientations. Recently, several platinum group metal complexes featuring the flexible, ambiphilic b-phosphinoethylborane ligand were reported in the literature; however, the impact of primary coordination sphere ligands and solvent on the properties of the Lewis acidic borane moiety remain underexplored. Rhodium and iridium complexes ligated by 9-borabicyclo[3.3.1]nonanyl-based b- diphenylphosphinoethylborane were studied using a combination of crystallography and 11B NMR spectroscopy. The studies revealed that both the primary coordination sphere and solvent had an impact on the formation of Lewis acid–base adducts. Specifically, inner-sphere Lewis pair formation was dependent on the nature of the X-type ligand bound to the metal center. Similar dependencies were identified with solvents in which Lewis acid interaction was found to correlate with solvent donor number. 

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