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1. Carbene-mediated synthesis of a germanium tris(dithiolene)dianion

   https://doi.org/10.1039/d0cc08206f  

   Tran, Phuong M.; Wang, Yuzhong; Xie, Yaoming; Wei, Pingrong; Schaefer, Henry F.; Robinson, Gregory H. (March 2021, Chemical Communications)

   While the 1 : 1 reaction of 3 with an N-heterocyclic carbene ({(Me)CN(i-Pr)} 2 C:) in THF resulted in ligand-substituted product 4, the corresponding 1 : 2 reaction (in the presence of H 2 O) gives the first structurally characterized germanium tris(dithiolene)dianion 5 as the major product and the “naked” dithiolene radical 6˙ as a minor by-product. The structure and bonding of 4 and 5 were probed by experimental and theoretical methods. Our study suggests that carbene-mediated partial hydrolysis may represent a new method to access tris(dithiolene) complexes of main-group elements. 

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2. 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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3. 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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4. Synthesis of a mononuclear magnesium bis(alkoxide) complex and its reactivity in the ring-opening copolymerization of cyclic anhydrides with epoxides

   https://doi.org/10.1039/C9DT04274A  

   Wannipurage, Duleeka; Hollingsworth, Thilini S.; Santulli, Federica; Cozzolino, Mariachiara; Lamberti, Marina; Groysman, Stanislav; Mazzeo, Mina (February 2020, Dalton Transactions)

   Synthesis of a new mononuclear magnesium complex with a bulky bis(alkoxide) ligand environment and its reactivity in ring-opening polymerization (ROP) and ring-opening copolymerization (ROCOP) are reported. Reaction of n -butyl- sec -butylmagnesium with two equivalents of HOR (HOR = di- tert -butylphenylmethanol, HOC t Bu 2 Ph) formed Mg(OR) 2 (THF) 2 . The reaction proceeded via the Mg(OR)( sec -Bu)(THF) 2 intermediate that was independently synthesized by treating n -butyl- sec -butylmagnesium with one equivalent of HOR. Mg(OR) 2 (THF) 2 led to active albeit not well-controlled ROP of rac -lactide. In contrast, well-controlled ROCOP of epoxides with cyclic anhydrides was observed, including efficient and alternating copolymerization of phthalic anhydride with cyclohexene oxide as well as rare copolymerization of phthalic anhydride with limonene oxide and terpolymerization of phthalic anhydride with both cyclohexene oxide and limonene oxide. In addition, novel copolymerization of dihydrocoumarin with limonene oxide is described. 

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5. Aziridination Reactivity of a Manganese(II) Complex with a Bulky Chelating Bis(Alkoxide) Ligand

   https://doi.org/10.3390/molecules27185751  

   Kurup, Sudheer S.; Woodland, Natalie M.; Lord, Richard L.; Groysman, Stanislav (September 2022, Molecules)

   Treatment of Mn(N(SiMe3)2)2(THF)2 with bulky chelating bis(alkoxide) ligand [1,1′:4′,1′′-terphenyl]-2,2′′-diylbis(diphenylmethanol) (H2[O-terphenyl-O]Ph) formed a seesaw manganese(II) complex Mn[O-terphenyl-O]Ph(THF)2, characterized by structural, spectroscopic, magnetic, and analytical methods. The reactivity of Mn[O-terphenyl-O]Ph(THF)2 with various nitrene precursors was investigated. No reaction was observed between Mn[O-terphenyl-O]Ph(THF)2 and aryl azides. In contrast, the treatment of Mn[O-terphenyl-O]Ph(THF)2 with iminoiodinane PhINTs (Ts = p-toluenesulfonyl) was consistent with the formation of a metal-nitrene complex. In the presence of styrene, the reaction led to the formation of aziridine. Combining varying ratios of styrene and PhINTs in different solvents with 10 mol% of Mn[O-terphenyl-O]Ph(THF)2 at room temperature produced 2-phenylaziridine in up to a 79% yield. Exploration of the reactivity of Mn[O-terphenyl-O]Ph(THF)2 with various olefins revealed (1) moderate aziridination yields for p-substituted styrenes, irrespective of the electronic nature of the substituent; (2) moderate yield for 1,1′-disubstituted α-methylstyrene; (3) no aziridination for aliphatic α-olefins; (4) complex product mixtures for the β-substituted styrenes. DFT calculations suggest that iminoiodinane is oxidatively added upon binding to Mn, and the resulting formal imido intermediate has a high-spin Mn(III) center antiferromagnetically coupled to an imidyl radical. This imidyl radical reacts with styrene to form a sextet intermediate that readily reductively eliminates the formation of a sextet Mn(II) aziridine complex. 

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