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1. A Heterogeneous Palladium Catalyst for the Polymerization of Olefins Prepared by Halide Abstraction Using Surface R 3 Si + Species

   https://doi.org/10.1002/anie.202117279  

   Gao, Jiaxin ; Dorn, Rick W. ; Laurent, Guillaume P. ; Perras, Frédéric A. ; Rossini, Aaron J. ; Conley, Matthew P. ( March 2022 , Angewandte Chemie International Edition)

   The silylium‐like surface species [ⁱPr₃Si][(R^FO)₃Al−OSi≡)] activates (N^N)Pd(CH₃)Cl (N^N=Ar−N=CMeMeC=N−Ar, Ar=2,6‐bis(diphenylmethyl)‐4‐methylbenzene) by chloride ion abstraction to form [(N^N)Pd−CH₃][(R^FO)₃Al−OSi≡)] (1). A combination of FTIR, solid‐state NMR spectroscopy, and reactions with CO or vinyl chloride establish that1shows similar reactivity patterns as (N^N)Pd(CH₃)Cl activated with Na[B(Ar^F)₄]. Multinuclear¹³C{²⁷Al} RESPDOR and¹H{¹⁹F} S‐REDOR experiments are consistent with a weakly coordinated ion‐pair between (N^N)Pd−CH₃⁺and [(R^FO)₃Al−OSi≡)].1catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd−CH₃]⁺in solution and incorporates up to 0.4 % methyl acrylate in copolymerization reactions.1produces polymers with significantly higher molecular weight than the solution catalyst, and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methylacrylate.

    

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2. A Heterogeneous Palladium Catalyst for the Polymerization of Olefins Prepared by Halide Abstraction Using Surface R 3 Si + Species

   https://doi.org/10.1002/ange.202117279  

   Gao, Jiaxin ; Dorn, Rick W. ; Laurent, Guillaume P. ; Perras, Frédéric A. ; Rossini, Aaron J. ; Conley, Matthew P. ( March 2022 , Angewandte Chemie)

   The silylium‐like surface species [ⁱPr₃Si][(R^FO)₃Al−OSi≡)] activates (N^N)Pd(CH₃)Cl (N^N=Ar−N=CMeMeC=N−Ar, Ar=2,6‐bis(diphenylmethyl)‐4‐methylbenzene) by chloride ion abstraction to form [(N^N)Pd−CH₃][(R^FO)₃Al−OSi≡)] (1). A combination of FTIR, solid‐state NMR spectroscopy, and reactions with CO or vinyl chloride establish that1shows similar reactivity patterns as (N^N)Pd(CH₃)Cl activated with Na[B(Ar^F)₄]. Multinuclear¹³C{²⁷Al} RESPDOR and¹H{¹⁹F} S‐REDOR experiments are consistent with a weakly coordinated ion‐pair between (N^N)Pd−CH₃⁺and [(R^FO)₃Al−OSi≡)].1catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd−CH₃]⁺in solution and incorporates up to 0.4 % methyl acrylate in copolymerization reactions.1produces polymers with significantly higher molecular weight than the solution catalyst, and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methylacrylate.

    

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3. Exploring Spin‐Orbit Effects in a [Cu 6 Tl] + Nanocluster Featuring an Uncommon Tl−H Interaction

   https://doi.org/10.1002/chem.202400390  

   Hertler, Phoebe R. ; Yu, Xiaojuan ; Brower, Jordan D. ; Nguyen, Thuy‐Ai D. ; Wu, Guang ; Autschbach, Jochen ; Hayton, Trevor W. ( March 2024 , Chemistry – A European Journal)

   Reaction of [CuH(PPh₃)]₆with 1 equiv. of Tl(OTf) results in formation of [Cu₆TlH₆(PPh₃)₆][OTf] ([1]OTf]), which can be isolated in good yields. Variable‐temperature¹H NMR spectroscopy, in combination with density functional theory (DFT) calculations, confirms the presence of a rare Tl−H orbital interaction. According to DFT, the¹H chemical shift of the Tl‐adjacent hydride ligands of[1]⁺includes 7.7 ppm of deshielding due to spin‐orbit effects from the heavy Tl atom. This study provides valuable new insights into a rare class of metal hydrides, given that[1][OTf]is only the third isolable species reported to contain a Tl−H interaction.

    

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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. 14-Electron Rh and Ir silylphosphine complexes and their catalytic activity in alkene functionalization with hydrosilanes

   https://doi.org/10.1039/D1DT00677K  

   Abeynayake, Niroshani S. ; Zamora-Moreno, Julio ; Gorla, Saidulu ; Donnadieu, Bruno ; Muñoz-Hernández, Miguel A. ; Montiel-Palma, Virginia ( August 2021 , Dalton Transactions)

   Herein we report an experimental and computational study of a family of four coordinated 14-electron complexes of Rh( iii ) devoid of agostic interactions. The complexes [X–Rh(κ 3 ( P,Si,Si )PhP( o -C 6 H 4 CH 2 Si i Pr 2 ) 2 ], where X = Cl (Rh-1), Br (Rh-2), I (Rh-3), OTf (Rh-4), Cl·GaCl 3 (Rh-5); derive from a bis(silyl)- o -tolylphosphine with isopropyl substituents on the Si atoms. All five complexes display a sawhorse geometry around Rh and exhibit similar spectroscopic and structural properties. The catalytic activity of these complexes and [Cl–Ir(κ 3 ( P,Si,Si )PhP( o -C 6 H 4 CH 2 Si i Pr 2 ) 2 ], Ir-1, in styrene and aliphatic alkene functionalizations with hydrosilanes is disclosed. We show that Rh-1 catalyzes effectively the dehydrogenative silylation of styrene with Et 3 SiH in toluene while it leads to hydrosilylation products in acetonitrile. Rh-1 is an excellent catalyst in the sequential isomerization/hydrosilylation of terminal and remote aliphatic alkenes with Et 3 SiH including hexene isomers, leading efficiently and selectively to the terminal anti-Markonikov hydrosilylation product in all cases. With aliphatic alkenes, no hydrogenation products are observed. Conversely, catalysis of the same hexene isomers by Ir-1 renders allyl silanes, the tandem isomerization/dehydrogenative silylation products. A mechanistic proposal is made to explain the catalysis with these M( iii ) complexes. 

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