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1. The Scandium(II) Carbonyl Complex (C ₅ H ₂ ^t Bu ₃ ) ₂ Sc(CO) and Its Isocyanide Analog (C ₅ H ₂ ^t Bu ₃ ) ₂ Sc(CNC ₆ H ₃ Me ₂ -2,6)

   https://doi.org/10.1021/jacs.4c09021  

   Queen, Joshua D; Goudzwaard, Quinn E; Rajabi, Ahmadreza; Ziller, Joseph W; Furche, Filipp; Evans, William J (September 2024, Journal of the American Chemical Society)

   Treatment of the scandium(II) metallocene Cpttt2Sc (Cpttt = C5H2tBu3) with CO or the isocyanide CNXyl (Xyl = C6H3Me2-2,6) yields the carbonyl complex Cpttt2Sc(CO), 1, or the isocyanide complex Cpttt2Sc(CNXyl), 2, which were identified by X-ray crystallography. Isotopic labeling with 13CO shows the CO stretch of 1 at 1875 cm−1 shifts to 1838 cm−1 in 1-13CO. The CN stretch in 2 is shifted to 1939 cm−1 compared to 2118 cm−1 for the free isocyanide. The 80.1 MHz (28.7 G) 45Sc hyperfine coupling in 1 and 74.7 MHz (26.8 G) in 2 are similar to the 82.6 MHz (29.6 G) coupling constant in Cpttt2Sc and indicate that 1 and 2 are Sc(II) complexes. A comprehensive analysis of the electronic structures of 1 and 2 using DFT calculations is reported. 

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2. Synthesis of Crystallographically Characterizable Bis(cyclopentadienyl) Sc(II) Complexes: (C ₅ H ₂ ^t Bu ₃ ) ₂ Sc and {[C ₅ H ₃ (SiMe ₃ ) ₂ ] ₂ ScI} ^1–

   https://doi.org/10.1021/jacs.3c11922  

   Queen, Joshua D.; Anderson-Sanchez, Lauren M.; Stennett, Cary R.; Rajabi, Ahmadreza; Ziller, Joseph W.; Furche, Filipp; Evans, William J. (February 2024, Journal of the American Chemical Society)

   The synthesis of previously unknown bis(cyclopentadienyl) complexes of the first transition metal, i.e., Sc(II) scandocene complexes, has been investigated using C5H2(tBu)3 (Cpttt), C5Me5 (Cp*), and C5H3(SiMe3)2 (Cp″) ligands. Cpttt 2ScI, 1, formed from ScI3 and KCpttt, can be reduced with potassium graphite (KC8) in hexanes to generate dark-red crystals of the first crystallographically characterizable bis(cyclopentadienyl) scandium(II) complex, Cpttt 2Sc, 2. Complex 2 has a 170.6° (ring centroid)-Sc-(ring centroid) angle and exhibits an eight-line EPR spectrum characteristic of Sc(II) with Aiso = 82.6 MHz (29.6 G). It sublimes at 200 °C at 10−4 Torr and has a melting point of 268−271 °C. Reductions of Cp*2ScI and Cp″2ScI under analogous conditions in hexanes did not provide new Sc(II) complexes, and reduction of Cp*2ScI in benzene formed the Sc(III) phenyl complex, Cp*2Sc(C6H5), 3, by C−H bond activation. However, in Et2O and toluene, reduction of Cp*2ScI at −78 °C gives a dark-red solution, 4, which displays an eight-line EPR pattern like that of 1, but it did not provide thermally stable crystals. Reduction of Cp″2ScI, in THF or Et2O at −35 °C in the presence of 2.2.2-cryptand, yields the green Sc(II) metallocene iodide complex, [K(crypt)][Cp″2ScI], 5, which was identified by X-ray crystallography and EPR spectroscopy and is thermally unstable. The analogous reaction of Cp*2ScI with KC8 and 18-crown-6 in Et2O gave the ligand redistribution product, [Cp*2Sc(18- crown-6-κ2O,O′)][Cp*2ScI2], 6, as the only crystalline product. Density functional theory 

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3. Synthesis and Oxidation of Dirhenium C ₄ , C ₆ , and C ₈ Complexes of the Formula (η ⁵ -C ₅ Me ₅ )Re(NO)(PR ₃ )(C⋮C) _n (R ₃ P)(ON)Re(η ⁵ -C ₅ Me ₅ ) (R = 4-C ₆ H ₄ R‘, c-C ₆ H ₁₁ ):  In Search of Dications and Radical Cations with Enhanced Stabilities ^†

   https://doi.org/10.1021/om000961m  

   Meyer, Wayne E.; Amoroso, Angelo J.; Horn, Clemens R.; Jaeger, Monika; Gladysz, J. A. (March 2001, Organometallics)
4. Synthesis and Reactivity of Functionalized Dimethylgermyl Complexes of the Formula (η ⁵ -C ₅ H ₅ )Re(NO)(PPh ₃ )(GeMe ₂ X); Equilibria Involving the Dimethylgermylene Complex [(η ⁵ -C ₅ H ₅ )Re(NO)(PPh ₃ )(=GeMe ₂ )]• TfO ⁻

   https://doi.org/10.1080/10426509408037445  

   Lee, Kenneth E.; Gladysz, J. A. (February 1994, Phosphorus, Sulfur, and Silicon and the Related Elements)
5. Crystal structure of the [(THF)Cs(μ-η ⁵ :η ⁵ -Cp′) ₃ Yb] _n oligomer

   https://doi.org/10.1107/S2056989020008051  

   Huh, Daniel N.; Ziller, Joseph W.; Evans, William J. (July 2020, Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   The green compound poly[(tetrahydrofuran)tris[μ-η 5 :η 5 -1-(trimethylsilyl)cyclopentadienyl]caesium(I)ytterbium(II)], [CsYb(C 8 H 13 Si) 3 (C 4 H 8 O)] n or [(THF)Cs(μ-η 5 :η 5 -Cp′) 3 Yb II ] n was synthesized by reduction of a red THF solution of (C 5 H 4 SiMe 3 ) 3 Yb III with excess Cs metal and identified by X-ray diffraction. The compound crystallizes as a two-dimensional array of hexagons with alternating Cs I and Yb II ions at the vertices and cyclopentadienyl groups bridging each edge. This, based off the six-electron cyclopentadienyl rings occupying three coordination positions, gives a formally nine-coordinate tris(cyclopentadienyl) coordination environment to Yb and the Cs is ten-coordinate due to the three cyclopentadienyl rings and a coordinated molecule of THF. The complex comprises layers of Cs 3 Yb 3 hexagons with THF ligands and Me 3 Si groups in between the layers. The Yb—C metrical parameters are consistent with a 4 f 14 Yb II electron configuration. 

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