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1. Carbene‐Stabilized Disilicon as a Silicon‐Transfer Agent: Synthesis of a Dianionic Silicon Tris(dithiolene) Complex

   https://doi.org/10.1002/anie.201916395  

   Wang, Yuzhong; Tope, Cynthia A.; Xie, Yaoming; Wei, Pingrong; Urbauer, Jeffrey L.; Schaefer, III, Henry F.; Robinson, Gregory H. (April 2020, Angewandte Chemie International Edition)

   Abstract Reaction of carbene‐stabilized disilicon (1) with the lithium‐based dithiolene radical (2^.) affords the first dianionic silicon tris(dithiolene) complex (3). Notably, the formation of3represents the unprecedented utilization of carbene‐stabilized disilicon (1) as a silicon‐transfer agent. The nature of3was probed by multinuclear NMR spectroscopy, single‐crystal X‐ray diffraction, and DFT computations. 

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2. Stable Boron Dithiolene Radicals

   https://doi.org/10.1002/anie.201804298  

   Wang, Yuzhong; Xie, Yaoming; Wei, Pingrong; Blair, Soshawn A.; Cui, Dongtao; Johnson, Michael K.; Schaefer, III, Henry F.; Robinson, Gregory H. (May 2018, Angewandte Chemie International Edition)

   Abstract Whereas low‐temperature (−78 °C) reaction of the lithium dithiolene radical1^.with boron bromide gives the dibromoboron dithiolene radical2^., the parallel reaction of1^.with (C₆H₁₁)₂BCl (0 °C) affords the dicyclohexylboron dithiolene radical3^.. Radicals2^.and3^.were characterized by single‐crystal X‐ray diffraction, UV/Vis, and EPR spectroscopy. The nature of these radicals was also probed computationally. Under mild conditions,3^.undergoes unexpected thiourea‐mediated B−C bond activation to give zwitterion4, which may be regarded as an anionic dithiolene‐modified carbene complex of the sulfenyl cation RS⁺(R=cyclohexyl). 

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3. Germanium(II) Dithiolene Complexes

   https://doi.org/10.1002/chem.202302258  

   Tran, Phuong_M; Wang, Yuzhong; Lahm, Mitchell_E; Wei, Pingrong; Molnar, Christopher_J; Schaefer, III, Henry_F; Robinson, Gregory_H (October 2023, Chemistry – A European Journal)

   Abstract The 1 : 2 reaction of the imidazole‐based dithiolate (2) with GeCl₂ • dioxane in THF/TMEDA gives3, a TMEDA‐complexed dithiolene‐based germylene. Compound3is converted to monothiolate‐complexed (5) and N‐heterocyclic carbene‐complexed (7) germanium(II) dithiolene complexes via Lewis base ligand exchange. A bis‐dithiolene‐based germylene (8), involving a 3c–4e S‐Ge‐S bond, has also been synthesized through controlled hydrolysis of7. The bonding nature of3,5, and8was investigated by both experimental and theoretical methods. 

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4. Lewis base-complexed magnesium dithiolenes

   https://doi.org/10.1039/C9CC03427G  

   Wang, Yuzhong; Maxi, Nirva A.; Xie, Yaoming; Wei, Pingrong; Schaefer, Henry F.; Robinson, Gregory H. (July 2019, Chemical Communications)

   The first magnesium-based dithiolene, 2 , was prepared by reaction of the lithium dithiolene radical, 1˙ , with 2-mesitylmagnesium bromide. Reaction of 2 with N-heterocyclic carbenes (in toluene) gave a carbene-stabilized magnesium monodithiolene complex, 3 . Complex 3 , in turn, is readily converted to a THF-solvated magnesium bis-dithiolene dianion, 4 , via partial hydrolysis in polar solvents ( i.e. , THF/CH 3 CN). Compounds 2 , 3 and 4 have been spectroscopically and structurally characterized and probed by DFT computations. 

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5. Combined Crossed Molecular Beams and Ab Initio Study of the Bimolecular Reaction of Ground State Atomic Silicon (Si; ³ P) with Germane (GeH ₄ ; X ¹ A ₁ )

   https://doi.org/10.1002/cphc.202100235  

   Krasnoukhov, Vladislav_S; Azyazov, Valeriy_N; Mebel, Alexander_M; Doddipatla, Srinivas; Yang, Zhenghai; Goettl, Shane; Kaiser, Ralf_I (June 2021, ChemPhysChem)

   Abstract The chemical dynamics of the elementary reaction of ground state atomic silicon (Si;³P) with germane (GeH₄; X¹A₁) were unraveled in the gas phase under single collision condition at a collision energy of 11.8±0.3 kJ mol⁻¹exploiting the crossed molecular beams technique contemplated with electronic structure calculations. The reaction follows indirect scattering dynamics and is initiated through an initial barrierless insertion of the silicon atom into one of the four chemically equivalent germanium‐hydrogen bonds forming a triplet collision complex (HSiGeH₃;³i1). This intermediate underwent facile intersystem crossing (ISC) to the singlet surface (HSiGeH₃;¹i1). The latter isomerized via at least three hydrogen atom migrations involving exotic, hydrogen bridged reaction intermediates eventually leading to the H₃SiGeH isomeri5. This intermediate could undergo unimolecular decomposition yielding the dibridged butterfly‐structured isomer¹p1(Si(μ‐H₂)Ge) plus molecular hydrogen through a tight exit transition state. Alternatively, up to two subsequent hydrogen shifts toi6andi7, followed by fragmentation of each of these intermediates, could also form¹p1(Si(μ‐H₂)Ge) along with molecular hydrogen. The overall non‐adiabatic reaction dynamics provide evidence on the existence of exotic dinuclear hydrides of main group XIV elements, whose carbon analog structures do not exist. 

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