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1. Lewis Acidity of the SbCl ₃ / o ‐chloranil System

   https://doi.org/10.1002/anie.202505893  

   Şit, Ferit; Hunter, Nathanael_H; Maltz, Logan_T; Gabbaï, François_P (May 2025, Angewandte Chemie International Edition)

   Abstract While SbCl₃is typically inert toward oxidation byortho‐quinones, we useo‐chloranil to show that the outcome of such reactions may be altered by the presence of a donor such as triphenylphosphine oxide, which readily traps the SbCl₃(cat^Cl) synthon (cat^Cl = tetrachlorocatecholate) in the form of the corresponding adduct Ph₃PO→SbCl₃(cat^Cl). The same reaction in the presence of a chloride salt affords the corresponding antimonate anion [Cl₄Sb(cat^Cl)]⁻. Computational studies indicate that the putative SbCl₃(cat^Cl) synthon has a higher chloride ion affinity than SbCl₅, suggesting significant Lewis acidity. This property is further demonstrated by the use of the SbCl₃/o‐chloranil system for both THF polymerization and a Friedel–Crafts‐type alkylation of benzene using 1‐fluorooctane. Finally, the reaction ofE‐stilbene witho‐chloranil in the presence of SbCl₃affords the corresponding benzodioxene, suggesting that SbCl₃may also operate as a redox‐active catalyst. 

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2. Electronic Structure of trans‐ [V ^II Cl ₂ (E(CH ₃ ) ₂ CH ₂ CH ₂ E(CH ₃ ) ₂ ) ₂ ], E=N, P

   https://doi.org/10.1002/ejic.202400395  

   Jafari, Mehrafshan_G; Zolnhofer, Eva_M; Fehn, Dominik; Heinemann, Frank_W; Opalade, Adedamola_A; Carroll, Patrick_J; Meyer, Karsten; Krzystek, J.; Ozarowski, Andrew; Mindiola, Daniel_J; et al (December 2024, European Journal of Inorganic Chemistry)

   Abstract Coordination complexes of general formulatrans‐[MX₂(R₂ECH₂CH₂ER₂)₂] (M^II=Ti, V, Cr, Mn; E=N or P; R=alkyl or aryl) are a cornerstone of coordination and organometallic chemistry. We investigate the electronic properties of two such complexes,trans‐[VCl₂(tmeda)₂] andtrans‐[VCl₂(dmpe)₂], which thus representtrans‐[MX₂(R₂ECH₂CH₂ER₂)₂] where M=V, X=Cl, R=Me and E=N (tmeda) and P (dmpe). These V^IIcomplexes haveS=3/2 ground states, as expected for octahedral d³. Their tetragonal distortion leads to zero‐field splitting (zfs) that is modest in magnitude (D≈0.3 cm⁻¹) relative to analogousS=1 Ti^IIand Cr^IIcomplexes. This parameter was determined from conventional EPR spectroscopy, but more effectively from high‐frequency and ‐field EPR (HFEPR) that determined the sign ofDas negative for the diamine complex, but positive for the diphosphine, which information had not been known for anytrans‐[VX₂(R₂ECH₂CH₂ER₂)₂] systems. The ligand‐field parameters oftrans‐[VCl₂(tmeda)₂] andtrans‐[VCl₂(dmpe)₂] are obtained using both classical theory andab initioquantum chemical theory. The results shed light not only on the electronic structure of V^IIin this environment, but also on differences between N and P donor ligands, a key comparison in coordination chemistry. 

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3. Molecular structure determination: Equilibrium structure of pyrimidine ( m -C ₄ H ₄ N ₂ ) from rotational spectroscopy ( r _e ^SE ) and high-level ab initio calculation ( r _e ) agree within the uncertainty of experimental measurement

   https://doi.org/10.1063/1.5144914  

   Heim, Zachary N.; Amberger, Brent K.; Esselman, Brian J.; Stanton, John F.; Woods, R. Claude; McMahon, Robert J. (March 2020, The Journal of Chemical Physics)
4. Generalized T _e ([O iii ])– T _e (He i ) Discrepancies in Ionized Nebulae: Possible Evidence of Case B Deviations and Temperature Inhomogeneities

   https://doi.org/10.3847/1538-4357/adc67a  

   Méndez-Delgado, J E; Skillman, E D; Aver, E; Morisset, C; Esteban, C; García-Rojas, J; Kreckel, K; Rogers, N_S J; Rosales-Ortega, F F; Arellano-Córdova, K Z; et al (June 2025, The Astrophysical Journal)

   Abstract The physics of recombination lines in the Heisinglet system is expected to be relatively simple, supported by accurate atomic models. We examine the intensities of Heisingletsλ3614, λ3965, λ5016, λ6678, and λ7281 and the triplet Heiλ5876 in various types of ionized nebulae and compare them with theoretical predictions to test the validity of the “Case B” recombination scenario and the assumption of thermal homogeneity. Our analysis includes 85 spectra from Galactic and extragalactic Hiiregions, 90 from star-forming galaxies, and 218 from planetary nebulae, all compiled by the Deep Spectra of Ionized Regions Database Extended (DESIRED-E) project. By evaluating the ratios Heiλ7281/λ6678 and Heiλ7281/λ5876, we determineT_e(Hei) and compare it with direct measurements ofT_e([Oiii]λ4363/λ5007). We find thatT_e(Hei) is systematically lower thanT_e([Oiii]) across most objects and nebula types. Additionally, we identify a correlation between the abundance discrepancy factor (ADF(O²⁺)) and the differenceT_e([Oiii]) –T_e(Hei) for planetary nebulae. We explore two potential explanations: photon loss fromn¹P → 1¹Stransitions and temperature inhomogeneities. Deviations from “Case B” may indicate photon absorption by Hirather than Heiand/or generalized ionizing photon escape, highlighting the need for detailed consideration of radiative transfer effects. If temperature inhomogeneities are widespread, identifying a common physical phenomenon affecting all ionized nebulae is crucial. Our results suggest that both scenarios can contribute to the observed discrepancies. 

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5. Macrobicyclic Dibridgehead Di(trialkyl)pnictogens E((CH ₂ ) _n ) ₃ E (E/ n = As/10, As/12, As/14, Sb/14) and Their Cage-like Metal Complexes: Syntheses, Structures, and Homeomorphic Isomerizations

   https://doi.org/10.1021/acs.organomet.4c00120  

   Zarcone, Samuel_R; Verardi, Peter_J; Chu, Gong_M; Bhuvanesh, Nattamai; Gladysz, John_A (May 2024, Organometallics)