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1. Thionation of the 2‐λ ⁵ ‐Phosphaquinolin‐2‐one Scaffold with Lawesson's Reagent

   https://doi.org/10.1002/ijch.202000085  

   Bard, Jeremy P.; McNeill, J. Nolan; Warren, Gabrielle I.; Zakharov, Lev N.; Johnson, Darren W.; Haley, Michael M. (December 2020, Israel Journal of Chemistry)

   Abstract Lawesson's reagent is one of the most common thionating reagents that has found use for several decades on a variety of carbonyl systems. Herein, we report the transformation of the 2‐λ⁵‐phosphaquinolin‐2‐one structure to its respective 2‐λ⁵‐phosphaquinolin‐2‐thione derivative. Solution‐state characterization of both P−OPh and P−Ph thio analogues, as well as solid‐state structures for the latter system, are reported. 

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2. Electron-impact excitation of the 5$$\varvec{^2\textbf{S}_{1/2} \rightarrow 5^2\textbf{P}_{1/2}}$$ and 5$$\varvec{^2\textbf{P}_{3/2}}$$ transitions in rubidium by 40 eV electrons: theory and experiment

   https://doi.org/10.1140/epjd/s10053-022-00413-7  

   Hamilton, K. R.; Zatsarinny, O.; Bartschat, K.; Predojević, B.; Šević, D.; Marinković, B. P.; Brunger, M. J. (May 2022, The European Physical Journal D)

   AbstractWe report on a series of detailed Breit-Pauli and Dirac B-spline R-matrix (DBSR) differential cross section (DCS) calculations for excitation of the$$5\,^2\textrm{S}_{1/2} \rightarrow 5\,^2\textrm{P}_{1/2}$$ $5{}^2{\text{S}}_{1/2}\to 5{}^2{\text{P}}_{1/2}$and$$5\,^2\textrm{S}_{1/2}\rightarrow 5\,^2\textrm{P}_{3/2}$$ $5{}^2{\text{S}}_{1/2}\to 5{}^2{\text{P}}_{3/2}$states in rubidium by 40 eV incident electrons. The early BP computations shown here were carried out with both 5 states and 12 states, while the DBSR models coupled 150 and 325 states, respectively. We also report corresponding results from a limited set of DCS measurements on the unresolved$$5\,^2\textrm{P}_{1/2,3/2}$$ $5{}^2{\text{P}}_{1/2,3/2}$states, with the experimental data being restricted to the scattered electron angular range 2–$$10^\circ $$ ${10}^{\circ }$. Typically, good agreement is found between our calculated and measured DCS for excitation of the unresolved$$5\,^2\textrm{P}_{1/2,3/2}$$ $5{}^2{\text{P}}_{1/2,3/2}$states, with best accord being found between the DBSR predictions and the measured data. The present theoretical and experimental results are also compared with predictions from earlier 40 eV calculations using the nonrelativistic Distorted-Wave Born Approximation and a Relativistic Distorted-Wave model. Graphic abstract 

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3. The Role of Oxygen in the Electrochemical Reduction of Ethyl 2-(2-(Bromomethyl)phenoxy)acetate at Carbon Cathodes in Dimethylformamide

   https://doi.org/10.1149/1945-7111/ab72ef  

   Simon, Tamir; Vasquez, Antonio; Kelcher, Austin R.; Olivares, Jacob A.; Ji, Chang (February 2020, Journal of The Electrochemical Society)

   Cyclic voltammetry (CV) and controlled-potential electrolysis (CPE) were employed to examine the direct reduction of ethyl 2-(2-(bromomethyl)phenoxy)acetate at carbon cathodes in dimethylformamide (DMF) containing tetramethylammonium tetrafluoroborate (TMABF₄) as the electrolyte. Cyclic voltammogram of the substrate exhibits a single irreversible cathodic wave with a peak potential of –1.75 V vs SCE, which is characteristic for the reduction of organic halides in aprotic solvents. Bulk electrolyses of ethyl 2-(2-(bromomethyl)phenoxy)acetate were carried out in the absence and presence of oxygen. The product distributions were obtained by gas chromatograph (GC) as well as gas chromatograph coupled to a mass spectrometer (GC−MS). Two bicyclic compounds, ethyl 2,3-dihydro-1-benzofuran-2-carboxylate and ethyl benzofuran-2-carboxylate, were found to be formed in a total yield of more than 40% in the presence of oxygen. The reaction mechanism, in which the oxygen plays a significant role, was proposed and discussed on the basis of this study. 

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4. Structure and Luminescence Studies of Salts of the Helical Dication, [Au ₂ (μ-bis(diphenylphosphine)ethane) ₂ ] ²⁺ and Comparison with Salts of [Au ₂ (μ-bis(diphenylphosphine)propane) ₂ ] ²⁺

   https://doi.org/10.1021/acs.inorgchem.3c01961  

   Costa, Sarah; Walters, Daniel T; McNamara, Lauren E; Olmstead, Marilyn M; Fettinger, James C; Balch, Alan L (October 2023, Inorganic Chemistry)

   Six salts ([Au2(μ-dppe)2](BF4)2·CHCl3, [Au2(μ- dppe)2](BF4)2·1,2-Cl2C2H4, [Au2(μ-dppe)2](PF6)2·CHCl3, [Au2(μ-dppe)2](PF6)2, [Au2(μ-dppe)2](SbF6)2, and [Au2(μ- dppe)2](OTf)2·2CHCl3), (dppe is bis(diphenylphosphine)ethane) containing the dication, [Au2(μ-dppe)2]2+, have been prepared and structurally characterized by single-crystal X-ray crystallography. Unlike the three-coordinate dppe-bridged dimers, Au2X2(μ-dppe)2 (X = Br, I), which show considerable variation in the distance between the gold(I) ions over the range 3.0995(10) to 3.8479(3) Å in various solvates, the structure of the helical dication, [Au2(μ- dppe)2], in the new salts is remarkably consistent with the Au···Au separation falling in the narrow range 2.8787(9) to 2.9593(5) Å. In the solid state, the six crystals display a green luminescence both at room temperature and at 77 K, which has been assigned as phosphorescence. However, solutions of the dication are not luminescent. Salts containing the analogous dication [Au2(μ-dppp)2](PF6)2 (dppp is bis(diphenylphosphine)propane) have been prepared to determine whether the longer bridging ligand might also twist into a helical shape. These salts include [Au2(μ- dppp)2](OTf)2 (OTf is triflate) and three crystalline forms of [Au2(μ-dppp)2](PF6)2: the solvate [Au2(μ-dppp)2](PF6)2·(CHCl3) and two polymorphs of the unsolvated salt. None of these crystals are luminescent, but all contain a similar dication, [Au2(μ- dppp)2]2+, that contains two nearly parallel, linear P−Au−P groups and a long separation between the gold ions that varies from 5.3409(4) to 5.6613(6)Å. 

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5. The Crystal Structure of BaZn ₂ Se ₂ (OH) ₂ Featuring Brownmillerite‐Type Layers

   https://doi.org/10.1002/zaac.202300072  

   Zhang, Chi; Wang, Yiran; Kamp, Kendall R.; Walters, Lauren N.; Ding, Fenghua; Rondinelli, James M.; Poeppelmeier, Kenneth R. (June 2023, Zeitschrift für anorganische und allgemeine Chemie)

   Abstract A bimetallic hydroxychalcogenide, BaZn₂Se₂(OH)₂, was synthesized through hydrothermal pouch methods. The single crystal X‐ray diffraction and electron diffraction indicates that the phase crystallizes in the orthorhombic space groupPnmaand is composed of anionic layers [ZnSe_3/3(OH)_1/1]⁻that are separated and charged balanced by Ba²⁺cations. The [ZnSe_3/3(OH)_1/1]^–layer comprises two unique Zn sites, which form interpenetrating zigzag chains with an in‐plane dipole moment and adopts a brownmillerite‐type structural motif. The adjacent layers contain tetrahedrally coordinated Zn chains of opposite handedness related by an inversion center, which cancel the microscopic dipoles to minimize the macroscopic electric polarization. The adoption of a brownmillerite structural motif in BaZn₂Se₂(OH)₂can be rationalized by the distinct charge difference between Se²⁻and OH⁻anions, which creates a sufficient dipole moment in the ZnSe₃(OH) tetrahedra to allow the occurrence of twisted chains. FTIR spectroscopy confirms the existence of OH⁻anions and DFT calculations indicate that BaZn₂Se₂(OH)₂is a semiconductor with a direct band gap. This work expands the chemistry of the brownmillerite family from traditional homoanionic oxides to multianion hydroxychalcogenides, offering a new opportunity to explore tunable structural complexity for better design of functional materials. 

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