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1. 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)

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

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

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

   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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3. 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)

   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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4. Directed Gas Phase Formation of the Elusive Silylgermylidyne Radical (H 3 SiGe, X 2 A′′)

   https://doi.org/10.1002/cphc.202000913  

   Yang, Zhenghai ; Doddipatla, Srinivas ; Kaiser, Ralf I. ; Krasnoukhov, Vladislav S. ; Azyazov, Valeriy N. ; Mebel, Alexander M. ( December 2020 , ChemPhysChem)

   The previously unknown silylgermylidyne radical (H₃SiGe; X²A′′) was prepared via the bimolecular gas phase reaction of ground state silylidyne radicals (SiH; X²Π) with germane (GeH₄; X¹A₁) under single collision conditions in crossed molecular beams experiments. This reaction begins with the formation of a van der Waals complex followed by insertion of silylidyne into a germanium‐hydrogen bond forming the germylsilyl radical (H₃GeSiH₂). A hydrogen migration isomerizes this intermediate to the silylgermyl radical (H₂GeSiH₃), which undergoes a hydrogen shift to an exotic, hydrogen‐bridged germylidynesilane intermediate (H₃Si(μ‐H)GeH); this species emits molecular hydrogen forming the silylgermylidyne radical (H₃SiGe). Our study offers a remarkable glance at the complex reaction dynamics and inherent isomerization processes of the silicon‐germanium system, which are quite distinct from those of the isovalent hydrocarbon system (ethyl radical; C₂H₅) eventually affording detailed insights into an exotic chemistry and intriguing chemical bonding of silicon‐germanium species at the microscopic level exploiting crossed molecular beams.

    

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5. Cleavage of Carbon Dioxide C=O Bond Promoted by Nickel‐Boron Cooperativity in a PBP‐Ni Complex

   https://doi.org/10.1002/ange.202306315  

   Álvarez‐Rodríguez, Lucía ; Ríos, Pablo ; Laglera‐Gándara, Carlos J. ; Jurado, Andrea ; Fernández‐de‐Córdova, Francisco José ; Gunnoe, T. Brent ; Rodríguez, Amor ( July 2023 , Angewandte Chemie)

   The synthesis and characterization of (^tBuPBP)Ni(OAc) (5) by insertion of carbon dioxide into the Ni−C bond of (^tBuPBP)NiMe (1) is presented. An unexpected CO₂cleavage process involving the formation of new B−O and Ni−CO bonds leads to the generation of a butterfly‐structured tetra‐nickel cluster (^tBuPBOP)₂Ni₄(μ‐CO)₂(6). Mechanistic investigation of this reaction indicates a reductive scission of CO₂by O‐atom transfer to the boron atom via a cooperative nickel‐boron mechanism. The CO₂activation reaction produces a three‐coordinate (^tBuP₂BO)Ni‐acyl intermediate (A) that leads to a (^tBuP₂BO)−Ni^Icomplex (B) via a likely radical pathway. The Ni^Ispecies is trapped by treatment with the radical trap (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) to give (^tBuP₂BO)Ni^II(η²‐TEMPO) (7). Additionally,¹³C and¹H NMR spectroscopy analysis using¹³C‐enriched CO₂provides information about the species involved in the CO₂activation process.

    

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