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1. Bis(catecholato-κ ² O , O ′)bis(dimethyl sulfoxide-κ O )titanium(IV)

   https://doi.org/10.1107/S2056989022002638  

   Hewage, Nisansala; Mastriano, Carolyn; Brückner, Christian; Zeller, Matthias (April 2022, Acta Crystallographica Section E Crystallographic Communications)

   Bis(benzene-1,2-diolato-κ 2 O , O ′)bis(dimethyl sulfoxide-κ O )titanium(IV), [Ti(C 6 H 4 O 2 ) 2 (C 2 H 6 OS) 2 ], crystallizes with two crystallographically independent molecules in the space group P 2 1 / c emulating orthorhombic Pbca symmetry (β = 90.0445 (9)°]. The two molecules are related by pseudo-glide symmetry, broken by modulation of each one catecholate and dimethyl sulfoxide (DMSO) ligand. Twinning by pseudomerohedry was observed [twin ratio 0.5499 (7):0.4401 (7)]. Complex 3 was obtained by heating of diprotonated titanium tris-catecholate precursor 2 H in DMSO, by formal displacement of a catechol molecule by two DMSO molecules. Complex 3 is just the second heteroleptic, mono-nuclear, neutral bis-catecholate complex with TiO 6 metal coordination, the only other one being its bis-DMF analogue 6 . The two molecules of 3 exhibit a distorted octahedral geometry. The geometry and distortions from ideal symmetry of 3 are discussed and compared to 6 and to cationic tris-catecholate titanium complexes. 

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2. Electronic stabilization by occupational disorder in the ternary bismuthide Li _3–x–y In _x Bi ( x  ≃ 0.14, y  ≃ 0.29)

   https://doi.org/10.1107/S2053229620006439  

   Ovchinnikov, Alexander; Bobev, Svilen (June 2020, Acta Crystallographica Section C Structural Chemistry)

   null (Ed.)

   A ternary derivative of Li 3 Bi with the composition Li 3– x – y In x Bi ( x  ≃ 0.14, y  ≃ 0.29) was produced by a mixed In+Bi flux approach. The crystal structure adopts the space group Fd \overline{3} m (No. 227), with a = 13.337 (4) Å, and can be viewed as a 2 × 2 × 2 superstructure of the parent Li 3 Bi phase, resulting from a partial ordering of Li and In in the tetrahedral voids of the Bi fcc packing. In addition to the Li/In substitutional disorder, partial occupation of some Li sites is observed. The Li deficiency develops to reduce the total electron count in the system, counteracting thereby the electron doping introduced by the In substitution. First-principles calculations confirm the electronic rationale of the observed disorder. 

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3. A three body problem: a genuine hetero tri metallic molecule vs. a mixture of two parent hetero bi metallic molecules

   https://doi.org/10.1039/c8sc00917a  

   Han, Haixiang; Wei, Zheng; Barry, Matthew C.; Carozza, Jesse C.; Alkan, Melisa; Rogachev, Andrey Yu; Filatov, Alexander S.; Abakumov, Artem M.; Dikarev, Evgeny V. (January 2018, Chemical Science)

   This work raises a fundamental question about the “real” structure of molecular compounds containing three different metals: whether they consist of genuine hetero tri metallic species or of a mixture of parent hetero bi metallic species. Heterotrimetallic complex Li 2 CoNi(tbaoac) 6 ( 1 , tbaoac = tert -butyl acetoacetate) has been designed based on the model tetranuclear structure featuring two transition metal sites in order to be utilized as a molecular precursor for the low-temperature preparation of the LiCo 0.5 Ni 0.5 O 2 battery cathode material. An investigation of the structure of 1 appeared to be very challenging, since the Co and Ni atoms have very similar atomic numbers, monoisotopic masses, and radii as well as the same oxidation state and coordination number/environment. Using a statistical analysis of heavily overlaid isotope distribution patterns of the [Li 2 MM′L 5 ] + (M/M′ = Co 2 , Ni 2 , and CoNi) ions in DART mass spectra, it was concluded that the reaction product 1 contains both heterotrimetallic and bimetallic species. A structural analogue approach has been applied to obtain Li 2 MMg(tbaoac) 6 (M = Co ( 2 ) and Ni ( 3 )) complexes that contain lighter, diamagnetic magnesium in the place of one of the 3d transition metals. X-ray crystallography, mass spectrometry, and NMR spectroscopy unambiguously confirmed the presence of three types of molecules in the reaction mixture that reaches an equilibrium, Li 2 M 2 L 6 + Li 2 Mg 2 L 6 ↔ 2Li 2 MMgL 6 , upon prolonged reflux in solution. The equilibrium mixture was shown to have a nearly statistical distribution of the three molecules, and this is fully supported by the results of theoretical calculations revealing that the stabilization energies of hetero tri metallic assemblies fall exactly in between those for the parent hetero bi metallic species. The LiCo 0.5 Ni 0.5 O 2 quaternary oxide has been obtained in its phase-pure form by thermal decomposition of heterometallic precursor 1 at temperatures as low as 450 °C. Its chemical composition, structure, morphology, and transition metal distribution have been studied by X-ray and electron diffraction techniques and compositional energy-dispersive X-ray mapping with nanometer resolution. The work clearly illustrates the advantages of heterometallic single-source precursors over the corresponding multi-source precursors. 

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4. Nonlinear photocarrier dynamics in multilayer W S e ₂ induced by intense terahertz pulses

   https://doi.org/10.1364/JOSAB.504204  

   Guay, Viela; Johnson, Nathan; Zhang, Yue; van_der_Zande, Arend_M; Thorp, Spencer_G; Graham, Matthew; Lee, Yun-Shik (November 2023, Journal of the Optical Society of America B)

   Non-equilibrium photocarriers in multilayer WSe₂injected by femtosecond laser pulses exhibit extraordinary nonlinear dynamics in the presence of intense THz fields. The THz absorption in optically excited WSe₂rises rapidly in the low THz field regime and gradually ramps up at high intensities. The strong THz pulses drive the photocarriers into sidebands of higher mobility and release trapped charge carriers, which consequently enhance the transient conductivity of WSe₂. The spectrally analyzed conductivity reveals distinctive features, indicating that the photocarriers undergo resonant interactions such as carrier-photon scattering. 

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5. In situ etching of β -Ga2O3 using tert -butyl chloride in an MOCVD system

   https://doi.org/10.1063/5.0239152  

   Gorsak, Cameron_A; Bowman, Henry_J; Gann, Katie_R; Buontempo, Joshua_T; Smith, Kathleen_T; Tripathi, Pushpanshu; Steele, Jacob; Jena, Debdeep; Schlom, Darrell_G; Xing, Huili_Grace; et al (December 2024, Applied Physics Letters)

   In this study, we investigate in situ etching of β-Ga2O3 in a metalorganic chemical vapor deposition system using tert-butyl chloride (TBCl). We report etching of both heteroepitaxial 2¯01-oriented and homoepitaxial (010)-oriented β-Ga2O3 films over a wide range of substrate temperatures, TBCl molar flows, and reactor pressures. We infer that the likely etchant is HCl (g), formed by the pyrolysis of TBCl in the hydrodynamic boundary layer above the substrate. The temperature dependence of the etch rate reveals two distinct regimes characterized by markedly different apparent activation energies. The extracted apparent activation energies suggest that at temperatures below ∼800 °C, the etch rate is likely limited by desorption of etch products. The relative etch rates of heteroepitaxial 2¯01 and homoepitaxial (010) β-Ga2O3 were observed to scale by the ratio of the surface energies, indicating an anisotropic etch. Relatively smooth post-etch surface morphology was achieved by tuning the etching parameters for (010) homoepitaxial films. 

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