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1. Sr(Ag 1−x Li x ) 2 Se 2 and [Sr 3 Se 2 ][(Ag 1−x Li x ) 2 Se 2 ] Tunable Direct Band Gap Semiconductors

   https://doi.org/10.1002/ange.202301191  

   Zhou, Xiuquan ; Wilfong, Brandon ; Chen, Xinglong ; Laing, Craig ; Pandey, Indra R. ; Chen, Ying‐Pin ; Chen, Yu‐Sheng ; Chung, Duck‐Young ; Kanatzidis, Mercouri G. ( February 2023 , Angewandte Chemie)

   Synthesizing solids in molten fluxes enables the rapid diffusion of soluble species at temperatures lower than in solid‐state reactions, leading to crystal formation of kinetically stable compounds. In this study, we demonstrate the effectiveness of mixed hydroxide and halide fluxes in synthesizing complex Sr/Ag/Se in mixed LiOH/LiCl. We have accessed a series of two‐dimensional Sr(Ag_1−xLi_x)₂Se₂layered phases. With increased LiOH/LiCl ratio or reaction temperature, Li partially substituted Ag to form solid solutions of Sr(Ag_1−xLi_x)₂Se₂withxup to 0.45. In addition, a new type of intergrowth compound [Sr₃Se₂][(Ag_1−xLi_x)₂Se₂] was synthesized upon further reaction of Sr(Ag_1−xLi_x)₂Se₂with SrSe. Both Sr(Ag_1−xLi_x)₂Se₂and [Sr₃Se₂][(Ag_1−xLi_x)₂Se₂] exhibit a direct band gap, which increases with increasing Li substitution (x). Therefore, the band gap of Sr(Ag_1−xLi_x)₂Se₂can be precisely tuned via fine‐tuningxthat is controlled by only the flux ratio and temperature.

    

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2. Sr(Ag 1−x Li x ) 2 Se 2 and [Sr 3 Se 2 ][(Ag 1−x Li x ) 2 Se 2 ] Tunable Direct Band Gap Semiconductors

   https://doi.org/10.1002/anie.202301191  

   Zhou, Xiuquan ; Wilfong, Brandon ; Chen, Xinglong ; Laing, Craig ; Pandey, Indra R. ; Chen, Ying‐Pin ; Chen, Yu‐Sheng ; Chung, Duck‐Young ; Kanatzidis, Mercouri G. ( February 2023 , Angewandte Chemie International Edition)

   Synthesizing solids in molten fluxes enables the rapid diffusion of soluble species at temperatures lower than in solid‐state reactions, leading to crystal formation of kinetically stable compounds. In this study, we demonstrate the effectiveness of mixed hydroxide and halide fluxes in synthesizing complex Sr/Ag/Se in mixed LiOH/LiCl. We have accessed a series of two‐dimensional Sr(Ag_1−xLi_x)₂Se₂layered phases. With increased LiOH/LiCl ratio or reaction temperature, Li partially substituted Ag to form solid solutions of Sr(Ag_1−xLi_x)₂Se₂withxup to 0.45. In addition, a new type of intergrowth compound [Sr₃Se₂][(Ag_1−xLi_x)₂Se₂] was synthesized upon further reaction of Sr(Ag_1−xLi_x)₂Se₂with SrSe. Both Sr(Ag_1−xLi_x)₂Se₂and [Sr₃Se₂][(Ag_1−xLi_x)₂Se₂] exhibit a direct band gap, which increases with increasing Li substitution (x). Therefore, the band gap of Sr(Ag_1−xLi_x)₂Se₂can be precisely tuned via fine‐tuningxthat is controlled by only the flux ratio and temperature.

    

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3. 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 ( November 2024 , European Journal of Inorganic Chemistry)

   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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4. Isoelectronic perturbations to f - d -electron hybridization and the enhancement of hidden order in URu 2 Si 2

   https://doi.org/10.1073/pnas.2026591118  

   Wolowiec, Christian T. ; Kanchanavatee, Noravee ; Huang, Kevin ; Ran, Sheng ; Breindel, Alexander J. ; Pouse, Naveen ; Sasmal, Kalyan ; Baumbach, Ryan E. ; Chappell, Greta ; Riseborough, Peter S. ; et al ( May 2021 , Proceedings of the National Academy of Sciences)

   Electrical resistivity measurements were performed on single crystals of URu_2–xOs_xSi₂up tox= 0.28 under hydrostatic pressure up toP= 2 GPa. As the Os concentration,x, is increased, 1) the lattice expands, creating an effective negative chemical pressureP_ch(x); 2) the hidden-order (HO) phase is enhanced and the system is driven toward a large-moment antiferromagnetic (LMAFM) phase; and 3) less external pressureP_cis required to induce the HO→LMAFM phase transition. We compare the behavior of theT(x,P) phase boundary reported here for the URu_2-xOs_xSi₂system with previous reports of enhanced HO in URu₂Si₂upon tuning withPor similarly in URu_2–xFe_xSi₂upon tuning with positiveP_ch(x). It is noteworthy that pressure, Fe substitution, and Os substitution are the only known perturbations that enhance the HO phase and induce the first-order transition to the LMAFM phase in URu₂Si₂. We present a scenario in which the application of pressure or the isoelectronic substitution of Fe and Os ions for Ru results in an increase in the hybridization of the U-5f-electron and transition metald-electron states which leads to electronic instability in the paramagnetic phase and the concurrent formation of HO (and LMAFM) in URu₂Si₂. Calculations in the tight-binding approximation are included to determine the strength of hybridization between the U-5f-electron states and thed-electron states of Ru and its isoelectronic Fe and Os substituents in URu₂Si₂.

    

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5. A Dual Plating Battery with the Iodine/[ZnI x (OH 2 ) 4−x ] 2−x Cathode

   https://doi.org/10.1002/ange.201909324  

   Hong, Jessica J. ; Zhu, Liangdong ; Chen, Cheng ; Tang, Longteng ; Jiang, Heng ; Jin, Bei ; Gallagher, Trenton C. ; Guo, Qiubo ; Fang, Chong ; Ji, Xiulei ( September 2019 , Angewandte Chemie)

   Plating battery electrodes typically deliver higher specific capacity values than insertion or conversion electrodes because the ion charge carriers represent the sole electrode active mass, and a host electrode is unnecessary. However, reversible plating electrodes are rare for electronically insulating nonmetals. Now, a highly reversible iodine plating cathode is presented that operates on the redox couples of I₂/[ZnI_x(OH₂)_4−x]^2−xin a water‐in‐salt electrolyte. The iodine plating cathode with the theoretical capacity of 211 mAh g⁻¹plates on carbon fiber paper as the current collector, delivering a large areal capacity of 4 mAh cm⁻². Tunable femtosecond stimulated Raman spectroscopy coupled with DFT calculations elucidate a series of [ZnI_x(OH₂)_4−x]^2−xsuperhalide ions serving as iodide vehicles in the electrolyte, which eliminates most free iodide ions, thus preventing the consequent dissolution of the cathode‐plated iodine as triiodides.

    

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